Elenco Electronics Snap Circuits STEM, SCSTEM1 Instruction Manual And Recipe Book

Copyright © 2017 by Elenco®Electronics, Inc. All rights reserved. No part of this book shall be reproduced by 753136
any means; electronic, photocopying, or otherwise without written permission from the publisher.

U.S. Patents: 7,144,255; 7,273,377, & patents pending

Instruction Manual

Projects 1 - 93

Project 3

8-108

AGES

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-1-

1. Most circuit problems are due to incorrect assem­bly, always double-check that your circuit exactly
matches the drawing for it.

2. Be sure that parts with positive/negative markings
are positioned as per the drawing.

3. Be sure that all connections are securely snapped.

4. Try replacing the batteries.

Elenco®is not responsible for parts damaged due to
incorrect wiring.

Basic Troubleshooting

Note: If you suspect you have damaged parts, you can follow

the Advanced Troubleshooting procedure on page 11 to deter­mine which ones need replacing.

Basic Troubleshooting 1

Parts List 2

How to Use It 3

Assembling the Build-Your-Own Electromagnet 4

Guidelines for Use in Classrooms & Home School 4

About Your Snap Circuits

®

Parts 5-8

Introduction to Electricity 9

DOs and DON’Ts of Building Circuits 10

Advanced Troubleshooting 11

Project Listings 12

Projects 1 - 93 13 - 74

Test Your Knowledge 75

Other Snap Circuits

®

Projects 76

Block Layout Back Cover

Table of Contents

WARNING: Always check your wiring

before turning on a circuit. Never leave
a circuit unattended while the batteries
are installed. Never connect additional
batteries or any other power sources to
your circuits. Discard any cracked or
broken parts.

Adult Supervision: Because children’s

abilities vary so much, even with age
groups, adults should exercise discre­tion as to which experiments are suit­able and safe (the instructions should
enable supervising adults to establish

the experiment’s suitability for the
child). Make sure your child reads and
follows all of the relevant instructions
and safety procedures, and keeps them
at hand for reference.

This product is intended for use by
adults and children who have attained
sufficient maturity to read and follow
directions and warnings.

Never modify your parts, as doing so
may disable important safety features
in them, and could put your child at risk
of injury.

 Use only 1.5V AA type, alkaline batteries

(not included).
 Insert batteries with correct polarity.
 Non-rechargeable batteries should not

be recharged. Rechargeable batteries

should only be charged under adult su-

pervision, and should not be recharged

while in the product.
 Do not mix old and new batteries.

 Do not connect batteries or battery

holders in parallel.

 Do not mix alkaline, standard (carbon-

zinc), or rechargeable (nickel-cadmium)
batteries.



Remove batteries when they are used up.

 Do not short circuit the battery termi-

nals.

 Never throw batteries in a fire or attempt

to open its outer casing.

 Batteries are harmful if swallowed, so

keep away from small children.

Batteries:

!

WARNING: CHOKING HAZARD -

Small parts. Not for children under 3 years.

!

Conforms to all applicable U.S.

government requirements and

CAN ICES-3 (B)/NMB-3 (B).

!

WARNING: Moving parts. Do not touch the fan while it is spinning.

WARNING: SHOCK HAZARD - Never connect Snap

Circuits

®

to the electrical outlets in your home in any way!

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-2-

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER. Call toll-free [phone] or e-mail us at: [e-mail].

Customer Service ● 150 Carpenter Ave. ● Wheeling, IL 60090 U.S.A.

Parts List (Colors and styles may vary) Symbols and Numbers

Qty. ID Name Symbol Part # Qty. ID Name Symbol Part #

r 3

1-Snap Wire 6SC01

r 1

String 6SCM1S

r 6

2-Snap Wire 6SC02

r 1

Spare Motor Top 6SCM1T

r 3

3-Snap Wire 6SC03

r 1

Electromagnet 6SCM3

r 1

4-Snap Wire 6SC04

r 2

Iron Core Rod (46mm)

6SCM3C

r 1

5-Snap Wire 6SC05

r 1

Bag of Paper Clips 6SCM3P

r 1

6-Snap Wire 6SC06

r 1

Meter 6SCM5

r 1

Battery Holder - uses
3 1.5V type AA (not included)

6SCB3

r 1

Magnet 6SCMAG

r 1

Base Grid (11.0” x 7.7”)

6SCBG

r 1

Nut Snap 6SCNS

r 1

Compass 6SCCOM

r 1

Two Spring Socket 6SCPY1

r 1

White LED 6SCD6

r 1

Slide Switch 6SCS1

r 1

Copper Electrode with Snap

6SCECS

r 1

Press Switch 6SCS2

r 1

Zinc Electrode with Snap

6SCEZS

r 1

Relay 6SCS3

r 1

Iron Fillings 6SCIF

r 1

Switcher 6SCS6

r 1

Jumper Wire (Black) 6SCJ1

r 1

Reed Switch 6SCS9

r 1

Jumper Wire (Red) 6SCJ2

r 1

Coil 6SCWIRE1

r 3

Lamp 6SCL4

r 2

Grommet 662510

r 1

Motor 6SCM1

r 1

Thin Rod MWK01P5

r 1

Glow Fan Blade 6SCM1FG

You may order additional / replacement parts at our website:

www.snapcircuits.net

M1

S2

M5

M3

6

5

4

3

2

1

B3

L4

N

S

D6

S1

S3

S6

S9

?1

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-3-

How to Use SnapCircuits

®

Snap Circuits®uses building blocks with snaps
to build the different electrical and electronic
circuits in the projects. Each block has a func­tion: there are switch blocks, light blocks, bat­tery blocks, different length wire blocks, etc.
These blocks are different colors and have
numbers on them so that you can easily iden­tify them. The blocks you will be using are
shown as color symbols with level numbers
next to them, allowing you to easily snap them
together to form a circuit.

For Example:

This is the switch block which is green and has
the marking on it. The part symbols in this
booklet may not exactly match the appearance
of the actual parts, but will clearly identify them.

This is a wire block which is blue and comes
in different wire lengths.
This one has the number , , ,
or on it depending on the length of the wire
connection required.

There is also a 1-snap wire that is used as a
spacer or for interconnection between different
layers.

You need a power source to build each circuit.
This is labeled and requires three (3) 1.5V
“AA” batteries (not included).

When installing a battery, be sure the spring
is compressed straight back, and not bent up,
down, or to one side.

A large clear plastic base grid is included with
this kit to help keep the circuit blocks properly
spaced. You will see evenly spaced posts that
the different blocks snap into. The base has
rows labeled A-G and columns labeled 1-10.

Next to each part in every circuit drawing is a
small number in black. This tells you which
level the component is placed at. Place all
parts on level 1 first, then all of the parts on
level 2, then all of the parts on level 3, etc.

Some circuits use the jumper wires to make
unusual connections. Just clip them to the
metal snaps or as indicated.

Usually when the motor is used, the glow
fan will usually be placed on it. On top of the
motor shaft is a black plastic piece (the motor
top) with three little tabs. Lay the fan on the
black piece so the slots in its bottom “fall into
place” around the three tabs in the motor top.
If not placed properly, the fan will fall off when
the motor starts to spin.

S2

2

3

4

5

Note: While building the projects, be careful
not to accidentally make a direct connection
across the battery holder (a “short circuit”),
as this may damage and/or quickly drain the
batteries.

B3

M1

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How to Use SnapCircuits

®

Assembling the build-your-own electromagnet:

You need the coil, an iron core rod, a grommet, and the 2-spring socket
(?1).

Wrap the coil around one of the iron core rods, leaving about 3 inches
free at both ends. Place a grommet on the end of the rod to help keep
the coil wire from coming off it.

Check that some of the protective coating has been removed
at each end, leaving about half an inch of bare wire. If the coil
wire is broken (or later gets broken) then use sandpaper or
steel wool to scrape off the protective coating for about half an
inch at each end.

Connect the bare wire ends to the springs on the 2-spring
socket (the springs must connect to the wire where the varnish
has been removed, otherwise it won’t make electrical contact).

GUIDELINESFORUSEINCLASSROOMSORHOMESCHOOLING:

This product is a tool for opening the exciting world of electronics, and its relationship to
magnetism. Following the Learn by Doing®concept, electronics & magnetism will be easy
for students to understand by using Snap Circuits®to build circuits as they learn about them.
This kit emphasizes the practical applications of electronics, without bogging down in math­ematics. This course is as much about science as about electronics & magnetism.

Why should students learn about electronics? Electronics plays an important and increasing
role in their everyday lives, and so some basic knowledge of it is good for all of them. Learn­ing about it teaches how to do scientific investigation, and the projects develop basic skills
needed in today's world.

This product is intended for ages 8 and up. The only prerequisite is basic reading skills.

It should take about 6 hours to do this entire book, or about 2 hours to read the Introduction
to Electricity (page 9) and do just the educational summary projects (shown on page 12).
Teachers should review the Project Listing (page 12) and decide what is best.

INSTRUCTOR PREPARATION/ORGANIZATION

● Determine what the learning environment will be. Will the students be learning independ­ently or in small groups? How much teacher instruction will there be for each section?
Will the students be reading the lesson as homework and then have limited teacher in­struction before performing the experiments? Decide when quizzes will be given and
how they will be organized.

● Allocate time within the session as needed for:

● Teacher instruction about the topics being covered during the session.

● Getting the Snap Circuits

®

components into the workspace.

● Teacher instruction about the specific projects to be performed during that ses­sion.

● Building and testing the circuits.

● Performing experiments (and teacher verification if desired).

● Dismantling the circuits and returning Snap Circuits

®

components to storage area.

● Reassembling the class for review.

● Make sure the students know their objectives for the day, how much time they will need

for cleanup, and where the materials are being stored.

● Students must understand that there are usually many ways of making the same circuit,
and that the instructor may not know all the answers. They are doing scientific investi­gation, and many circuit projects suggest variations to experiment with.

● Have students review the DO’s and DON’Ts of Building Circuits on page 10 at the begin­ning of each session.

Answers to quiz questions are at www.snapcircuits.net/scstem1

.

-4-

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About Your Snap Circuits

®

Parts

(Part designs are subject to change without notice).

The base grid is a plat-

form for mounting
parts and wires. It
functions like the
printed circuit boards
used in most elec-

tronic products, or

like how the walls are
used for mounting the electrical wiring in your
home.

BASEGRID

The blue snap wires

are wires used to con-

nect components.

They are used to trans-

port electricity and do not af-

fect circuit performance. They

come in different lengths to allow orderly

arrangement of connections on the base grid.

The red and black

jumper wires

make flexible con­nections for times
when using the snap wires
would be difficult. They also
are used to make connections off the base grid.

Wires transport electricity just like pipes are used
to transport water. The colorful plastic coating
protects them and prevents electricity from get­ting in or out.

The batteries (B3) produce an electrical

voltage

using a chemical reaction. This “voltage” can be
thought of as electrical pressure, pushing elec­tricity through a circuit just like a pump pushes
water through pipes. This voltage is much lower
and much safer than that used in your house
wiring. Using more batteries increases the “pres­sure”, therefore, more electricity flows.

The funny marking on the battery holder is the
standard battery symbol used in electrical wiring
diagrams. These wiring diagrams are called

schematics, and are used in everything from

house wiring to complex radios.

SNAP WIRES & JUMPER WIRES

BATTERY HOLDER

Battery Symbol

Battery Holder (B3)

Symbols

Slide &Press

Switches
(S1 & S2)

SWITCHES

The slide & press switches (S1 &S2) connect
(pressed or “ON”) or disconnect (not pressed or
“OFF”) the wires in a circuit. When ON they have
no effect on circuit performance. Switches turn
on electricity just like a faucet turns on water from
a pipe.

Reed Switch (S9)

The reed switch (S9) is an electrical switch that
can be controlled by a magnet. It has two metal
contacts close together. The magnetic field from
the magnet makes the contacts come together,
completing a circuit just like other switches do.

The switcher (S6) is a more complex switch used
to reverse the wires to a component or circuit. See
project 2 for an example of connections.

Switcher (S6)

Its symbol & connections look like this:

Symbol

-5-

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About Your Snap Circuits

®

Parts

How does electricity turn the shaft in the motor?
The answer is magnetism. Electricity is closely
related to magnetism, and an electric current
flowing in a wire has a magnetic field similar to
that of a very, very tiny magnet. Inside the motor
is a coil of wire with many loops wrapped around
metal plates. This is called an electromagnet. If
a large electric current flows through the loops,
it will turn ordinary metal into a magnet. The
motor shell also has a magnet on it. When elec­tricity flows through the electromagnet, it repels
from the magnet on the motor shell and the shaft
spins. If the fan is on the motor shaft, then its
blades will create airflow.

The meter (M5) is an important measuring de­vice. You will use it to measure the voltage (elec­trical pressure) and current (how fast electricity
is flowing) in a circuit.

The electrical symbol for a meter is shown below.

The meter measures voltage when connected in
parallel to a circuit and measures the current
when connected in series in a circuit.

This meter has one voltage scale (5V) and two
current scales (1mA and 1A). These use the
same meter but with internal components that
scale the measurement into the desired range.
This will be explained more later. Note: Your M5
meter is a simple meter. Don’t expect it to be as
accurate as normal electronic test instruments.

The motor (M1) converts electricity into mechan-
ical motion. An electric current in the motor will
turn the shaft and the motor blades, and the fan
blade if it is on the motor. The electrical symbol
for a motor is also shown here.

METER

MOTOR

Meter Symbol

Magnet

Coil

Pointer

Contacts

Motor Symbol

Magnet

Electromagnet

Shaft

Power Contacts

Shell

Meter (M5)

Motor (M1)

Inside the meter there is a fixed magnet and a
moveable coil around it. As current flows through
the coil, it creates a magnetic field. The interac­tion of the two magnetic fields causes the coil
(connected to the pointer) to move (deflect).

Glow-in-the-dark Fan

-6-

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About Your Snap Circuits

®

Parts

A light bulb, such as in the 4.5V lamps (L4), con-
tains a special thin high-resistance wire. When a
lot of electricity flows through, this wire gets so
hot it glows bright. Voltages above the bulb’s rat­ing can burn out the wire.

The electrical symbol for a lamp is shown here,
though other symbols are also used in the industry.

LAMP

Lamp Symbol

The electromagnet (M3) is a large coil of wire,
which acts like a magnet when electricity flows
through it. Placing an iron bar inside increases
the magnetic effects. The electromagnet can
store electrical energy in a magnetic field.

The properties of the electromagnet will be ex­plained in the projects. Note that magnets can
erase magnetic media like computer disks.

The grommet will be used to hold the iron core
rod on the electromagnet.

ELECTROMAGNET

Electromagnet (M3)

Iron Core Rod

(usually placed in

electromagnet)

Electromagnet Sym-

bol with Rod Inside

Grommet

OTHER PARTS

The magnet is an ordinary magnet
like those in your home.

The compass is
a standard compass.
The red needle will
point toward the
strongest magnetic
field around it, usually
the north pole of the
earth.

The iron filings are tiny
fragments of iron in a
sealed case. They
will be used in
m a g ne t i s m
projects.

The copper and zinc elec-
trodes are just metals that
will be used for electro-chem­ical projects. They have
snaps attached for easy con­nection.

The nut-snap is an iron nut
mounted on a snap for special
projects.

The string will be used
in special projects. You
can use your own
string if you need more.

The thin rod is an iron
bar for special projects.

The Paper Clips will be
used for special proj­ects. You can use your
own if you need more,
but they must be metal.

The spare motor top is provided in
case you break the one on the
motor. Use a screwdriver to pry
the broken one off the motor,
then push the spare one on.

Electromagnet Sym-

bol without Rod

(a coil of wire)

Lamp (L4)

-7-

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About Your Snap Circuits

®

Parts

LED

White LED (D6)

The white LED(D6) is a light emitting diode, and
may be thought of as a special one-way light
bulb. In the “forward” direction, (indicated by the
“arrow” in the symbol) electricity flows if the volt­age exceeds a turn-on threshold brightness then
increases. A high current will burn out an LED,
so the current must be limited by other compo­nents in the circuit (Snap Circuits

®

LEDs have in­ternal resistors added, to protect them in case
you make wiring mistakes). LEDs block electricity
in the “reverse” direction.

COM

Relay:

Coil - connection to coil
Coil - connection to coil
NC - normally closed contact
NO - normally open contact
COM - common

See project 69 for an example of proper connections.

Coil

Coil

NO

NC

The relay (S3) is an electronic switch with contacts
that can be closed or opened. It contains a coil that
generates a magnetic field when current flows
through it. The magnetic field attracts an iron arma­ture, which switches the contacts. See project 69 for
further explanation.

RELAY

Relay (S3)

Two Spring Socket

Two Spring
Socket (?1)

The two-spring socket (?1) just has two
springs, and won’t do anything by itself. In this
set it is used to make the build-your-own electro­magnet, as per page 5. It can also be used by
advanced users to connect other electronic com­ponents to Snap Circuits

®

for creating your own

circuits.

LED Symbol

Relay Symbol

-8-

The symbols for the parts shown in
this section are used by engineers in
drawings of their circuits, called
schematics. Wires connecting com­ponents are shown as lines, with a
dot indicating a connection between
lines that cross. Here are schematics
of some of the circuits you will build:

SCHEMATICS

Project 14 Schematic:

Project 27 Schematic:

Project 43 Schematic:

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-9-

Introduction to Electricity

What is electricity? Nobody really knows. We only know how to produce it, under­stand its properties, and how to control it. Electricity is the movement of sub-atomic
charged particles (called electrons) through a material due to electrical pressure
across the material, such as from a battery.

Power sources, such as batteries, push electricity through a circuit, like a pump
pushes water through pipes. Wires carry electricity, like pipes carry water. Devices
like LEDs, motors, and speakers use the energy in electricity to do things. Switches
and transistors control the flow of electricity like valves and faucets control water.
Resistors limit the flow of electricity.

The electrical pressure exerted by a battery or other power source is called volt-
age and is measured in volts (V). Notice the “+” and “–” signs on the battery; these
indicate which direction the battery will “pump” the electricity.

The electric current is a measure of how fast electricity is flowing in a wire, just
as the water current describes how fast water is flowing in a pipe. It is expressed
in amperes (A) or milliamps (mA, 1/1000 of an ampere).

The “power” of electricity is a measure of how fast energy is moving through a
wire. It is a combination of the voltage and current (Power = Voltage x Current). It
is expressed in watts (W).

The resistance of a component or circuit represents how much it resists the elec­trical pressure (voltage) and limits the flow of electric current. The relationship is
Voltage = Current x Resistance. When the resistance increases, less current flows.
Resistance is measured in ohms (W), or kilo ohms (kW, 1000 ohms).

Nearly all of the electricity used in our world is produced at enormous generators
driven by steam or water pressure. Wires are used to efficiently transport this en­ergy to homes and businesses where it is used. Motors convert the electricity back
into mechanical form to drive machinery and appliances. The most important as­pect of electricity in our society is that it allows energy to be easily transported
over distances.

Note that “distances” includes not just large distances but also tiny distances. Try
to imagine a plumbing structure of the same complexity as the circuitry inside a
portable radio - it would have to be large because we can’t make water pipes so
small. Electricity allows complex designs to be made very small.

There are two ways of arranging parts in a circuit, in series or
in parallel. Here are examples:

Placing components in series increases the resistance; highest
value dominates. Placing components in parallel decreases the
resistance; lowest value dominates.

The parts within these series and parallel sub-circuits may be
arranged in different ways without changing what the circuit
does. Large circuits are made of combinations of smaller series
and parallel circuits.

Series Circuit

Parallel Circuit

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 10

DO’s and DON’Ts of Building Circuits

After building the circuits given in this booklet, you may wish to experi­ment on your own. Use the projects in this booklet as a guide, as many
important design concepts are introduced throughout them. Every circuit
will include a power source (the batteries), a resistance (which might be
a lamp, motor, electromagnet, etc.), and wiring paths between them and
back.

You must be careful not to create “short circuits” (very low-resis-

tance paths across the batteries, see examples below) as this will dam­age components and/or quickly drain your batteries. ELENCO®is not

responsible for parts damaged due to incorrect wiring.

Here are some important guidelines:

ALWAYS

USE EYE PROTECTION WHEN EXPERIMENTING ON YOUR
OWN.

ALWAYS include at least one component that will limit the current

through a circuit, such as a lamp, motor, or electromagnet.

ALWAYS use the meter and switches in conjunction with other com-

ponents that will limit the current through them. Failure to
do so will create a short circuit and/or damage those parts.

ALWAYS disconnect your batteries immediately and check your

wiring if something appears to be getting hot.

ALWAYS check your wiring before turning on a circuit.

NEVER connect to an electrical outlet in your home in any way.

NEVER leave a circuit unattended when it is turned on.

NEVER touch the motor when it is spinning at high speed.

For all of the projects given in this book, the parts may be arranged in
different ways without changing the circuit. For example, the order of
parts connected in series or in parallel does not matter — what matters
is how combinations of these sub-circuits are arranged together.

Examples of SHORTCIRCUITS - NEVERDOTHESE!!!

You are encouraged to tell us about new programs and circuits you create.
If they are unique, we will post them with your name and state on our web­site at: www.snapcircuits.net/learning_center/kids_creation.
Send your suggestions to ELENCO

®

: [e-mail].

ELENCO®provides a circuit designer so that you can make your own Snap
Circuits®drawings. This Microsoft®Word document can be downloaded
from: www.snapcircuits.net/learning_center/kids_creation or through
the www.snapcircuits.net website.

WARNING: SHOCK HAZARD - Never connect your Snaptric-

ity®set to the electrical outlets in your home in any way!

Placing a 3-snap wire directly across
the batteries is a SHORT CIRCUIT.

This is also a
SHORT CIRCUIT.

When the switch (S6)
is turned on, this large
circuit has a SHORT
CIRCUIT path (as
shown by the arrows).
The short circuit pre­vents any other por­tions of the circuit from
ever working.

NEVER

DO!

!

!

NEVER

DO!

!

NEVER

DO!

!

NEVER

DO!

Warning to Snap Circuits®owners: Do not connect addi-

tional voltage sources from other sets, or you may damage
your parts. Contact ELENCO

®

if you have questions or need

guidance.

!

-10-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 11

-11-

Advanced Troubleshooting

(Adult supervision recommended)

ELENCO®is not responsible for parts dam­aged due to incorrect wiring.

If you suspect you have damaged parts,
you can follow this procedure to systemat­ically determine which ones need replac­ing:

1. White LED(D6), 4.5V lamps (L4), motor

(M1), and battery holder(B3):

Place bat­teries in holder. Place each 4.5V lamp di­rectly across the battery holder, it should
light. Place the white LED directly across
the battery holder (LED + to battery +), it
should light. Do the same with the motor, it
should spin. If none work then replace your
batteries and repeat, if still bad then the bat­tery holder is damaged.
If the Motor (M1) does not balance the fan
evenly: Inspect the black plastic piece at
the top of the motor shaft, it should have 3
prongs. If missing or broken, replace it with
the spare that is included with this kit (a bro­ken one can be removed with a screw­driver). If the motor is fine, then inspect the
fan.

3.

Jumper wires: Use this mini-circuit to test

each jumper wire, the lamp should light.

4.

Snap wires: Use the mini-circuit below to

test each of the snap wires, one at a time.
The lamp should light.

5.

Two-spring socket (?1) and coil (the
build-your-own electromagnet): use the

mini-circuit in test step 4 but replace the 4­snap wire with ?1, with the coil connected
between its springs; the lamp should light. If
the lamp does not light be sure the protec­tive coating has been removed from the
ends of the coil wire where it attaches to the
springs; if necessary use sandpaper or steel
wool to scrape off the protective coating at
each end.

Switcher (S6): Build this mini-circuit. With the

switch in the middle position the motor (M1)
should be off; in the top position the motor
should spin counter-clockwise, and in the
bottom position the motor should spin clock­wise. Do not touch the motor while it is spin­ning.

6.

Slide switch (S1), press switch (S2), &
reed switch (S9): Build project 85. When

you press the switch, the white LED should
light. Replace the press switch with the slide
switch to test it. Replace the slide switch
with the reed switch, and hold a magnet
next to the switch to turn on the LED.

7.

Meter (M5): Build project 85, but replace

the 3-snap wire with the meter.

a. Set the meter to the 5V scale and push

the press switch. The meter should
read at least 2.5V.

b. Set the meter to the 1mA scale and

push the switch. The reading should be
over maximum.

c. Set the meter to the 1A scale and push

the switch. The meter should show a
small current.

8.

Electromagnet (M3): Build project 47 and

place the iron core rod in the electromagnet.
When you press the switch (S2), the rod in
the electromagnet should act like a magnet.

9.

Iron filings: Sometimes the filings may

stick to the case, making it appear cloudy.
Move a magnet (the one in this kit or a
stronger one in your home) across the case
to clean them off.

10.

Relay (S3): Build project 69. Turn on the

slide switch (S1); the lamp (L4) should be
on. Push the press switch (S2) to turn off
the lamp and turn on the white LED (D6).

ELENCO

®

150 Carpenter Avenue

Wheeling, IL 60090 U.S.A.

Phone: [phone]

Fax: [phone]

e-mail: [e-mail]

Website: www.elenco.com

You may order additional / replace-

ment parts at:

www.snapcircuits.net

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 12

Project # Description Page # Project # Description Page # Project # Description Page #

Project Listings (circuits with gold project numbers are the educational summary projects mentioned on page 4)

Fun Start

1 Lots of Lights 13
2 Flying Saucer 13
3 Electronic Playground 14

Fundamentals

4 Static Electricity 15
5 Light the Way (Lamp circuit) 17

6 Lights Bulbs of the Future 18

(LED circuit)
7 Ohm’s Law (Find lamp resistance) 18
8 Switches (4 types of switches) 19

9 Fuse 20

10 Materials Tester 21
(Conductors and insulators)
11 Make Your own Parts 22
(Resistance of water & pencils)
12 Motor Resistance 23
13 Electromagnet Resistance 23

Series & Parallel Circuits

14 Series Circuit (Lamps in series) 24
15 Series Circuit - Voltage 25

16 Parallel circuit (Lamps in parallel) 26

17 Parallel Circuit - Voltage 27
18 Parallel Swapping 28
19 Series Swapping 29
20 Batteries in Series 29
21 Lamp at Different Voltages 30
22 Motor at Different Voltages 31
23 LED at Different Voltages 31

24 Voltage Shifter 31

(Voltages in a series circuit)
25 Double Voltage Shifter 32

26 Double Switching Ammeter 33

(Currents in a series circuit)
27 Current Divider 34
(Currents in parallel circuits)
28 3 Currents 35
(Currents in parallel circuits)
29 AND Circuit 35

(AND gate with switches)

30 OR Circuit 36
(OR gate with switches)

Lamps &Motors

31 Light Bulb 36
(Incandescent light bulbs)
32 Light Bulb with Meter 37
33 2 Direction motor 38

(Reversing motor spin)

34 3-Speed Motor 39
(Adjusting motor speed with lamps)
35 3-Speed Motor - Voltage 40
36 3-Speed Motor with Fan 41
37 4-Speed Motor 42
38 Back EMF

(Motor characteristics) 42

39 Big Load 43
(Load effect on battery voltage)
40 Big Load - Voltage 44
41 Holding Down 45

(Overloading batteries)

42 Propellor and Fan (Motor direction) 46
43 Motor & Lights 47
44 Slow Motor & Lights 47

Magnetism &Electromagnetism

45 Compass 46

46 Magnetic Fields 47

47 Electronic Magnet 48
48 Electromagnet Magnetic Field 49
49 Electromagnet Tower 50

(Suspending iron rod in air)

50 Electromagnet Direction 51
(Reversing current)
51 Wire Magnet 51
(Magnetic field from wire)
52 Better Wire Magnet 52

53 Build-Your-Own Electromagnet 53

54 Build-Your-Own Electromagnet (II) 53
55 Magnetic Induction 54
(Induce a current in a coil)

56 Electromagnetic Induction 54

(Induce a current in another circuit)
57 Electromagnet Challange 55
58 Coil Resistance 55

Generators

59 Generator 56
(Harnessing fan energy)
60 Generator with Light 56

61 Motor with Flashes 57

62 Make Your Own Generator 57

63 High Speed Generator 58
(Use string to spin the motor faster)
64 Magnetic Energy Released 58
65 Relay Magnetic Energy Released 59

Magnetic Switches

66 Reed Switch 59

(Magnetically controlled switch)

67 Reed Switch with Electromagnet 60
68 Build-Your-Own Reed Switch 60

Relay Circuits

69 Relay 61
70 Relay Buzzer 62
71 Relay Buzzer Meter 62

72 Alternating Voltage 63

(Make an AC voltage using relay)
73 Super Buzzer 63
74 Transformer (Build a transformer) 64
75 Relay Memory 65
76 Relay Circuit 65
77 Build Your Own Relay 66
78 Build Your Own Buzzer 67
79 Build our Own Vibrating Circuit 67

Electricity from Liquids

80 Cola Power 68

(Use soda as a battery)

81 Fruit Power 68
(Use fruit as a battery)
82 Water Impurity Detector 69
(Current from water)

Fun Circuits

83 Swing the Magnet 70
84 Magic Rope Trick 70
(Suspend objects in air)
85 Morse Code 71
86 Hypnotic Discs (Spin patterns) 72
87 Spin Draw 73

88 2-Way Circuit 74

89 Electromagnet Music 74
90 Electromagnet Controlled Switch 75
91 Electromagnetic Playground 75
92 Magnetic Switcher 76
93 Circuits Fun 76

-12-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 13

Project 1

Lots of Lights

Build the circuit shown by placing all the parts with a black 1 next to them on the board first.
Then, assemble parts marked with a 2. Install three (3) “AA” batteries (not included) into the
battery holder (B3). Turn on the slide switch (S1); the lamps (L4) and white LED (D6) light.

Placement Level Numbers

+

NOTE: this circuit (and many others in this book) have an LED
being used without a resistor or other component to limit the
electric current through it. Normally this could damage an LED
but your Snap Circuits® LEDs include internal protection re­sistors, and will not be damaged. Be careful if you later use
other electrical sets with unprotected LEDs.

Project 2

Build the circuit as shown and place
the fan on the motor (M1). Be sure
the “+” side of the motor is on the left.

Push the press switch (S2) until the
motor reaches full speed, then re­lease it. The fan blade should rise and
float through the air like a flying
saucer. Be careful not to look directly
down on fan blade when it is spinning.

If the fan doesn’t fly off, then turn the
switch on and off several times rapidly
when it is at full speed. New alkaline
batteries work best.

+

!

WARNING: Moving parts. Do not

touch the fan or motor during operation.

!

WARNING: Do not

lean over the motor.

The air is being blown down through the blade and the motor rotation
locks the fan on the shaft. When the motor is turned off, the blade
unlocks from the shaft and is free to act as a propeller and fly through
the air. If speed of rotation is too slow, the fan will remain on the
motor shaft because it does not have enough lift to propel it. The
motor will spin faster when the batteries are new.

How does the fan rise? Think first about how you swim. When your
arms or legs push water behind you, your body moves ahead. A sim­ilar effect occurs in a helicopter - the spinning blades push air down,
and create an upward force on the blades. If the blades are spinning
fast enough, the upward force will be strong enough to lift the heli­copter off the ground.

While the switch is pressed, the motor rotation locks the fan on the
motor shaft. The fan does not spin fast enough to lift the entire circuit
off the ground. When the motor is turned off, the fan unlocks from
the shaft. The fan rises into the air like a helicopter, since it is no
longer held down by the weight of the full circuit.

Flying Saucer

-13-

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Project 3 Electronic Playground

Electronics is the science of working with
and controlling electricity. This circuit is
shown on the front of the Snap Circuits

®

STEM box, use that picture to help in
building it.

!

WARNING: Moving parts. Do not

touch the fan during operation.

Build the circuit as shown. Set the meter
(M5) to the 1A setting. Place the thin rod in
the electromagnet (M3). Place the glow fan
on the motor (M1). Assemble the build-your­own electromagnet as per the instructions
on page 5 (or you can assemble it later and
replace the 2-spring socket (?1) with a 3­snap wire).

Set the switcher (S6) to either side to light
the lamps (L4), spin the motor & fan, suck
the thin rod up into the electromagnet (M3),
and activate the build-your-own electromag­net. When activated, hold the build-your­own electromagnet near the compass to
attract the needle. The meter measures the
current.

Hold the magnet near the reed switch (S9)
to light the white LED (D6).

1A

!

WARNING:

Do not lean over the motor.

+

-14-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 15

Project 4

Static Electricity

These effects are caused by electricity. We call this
static electricity because the electrical charges are
not moving, although pulling clothes apart sounds like
static on a radio. When electricity is moving (usually
through wires) to do something in another place, we
call it an electric current.

Electricity is an attraction and repulsion of particles in
a material. All materials are made up of atoms, which
are really, really tiny. Atoms have a nucleus (which has
positive electrical charges), which is surrounded by tiny
electrons (negative electrical charges). When you rub
a material, electrons can move on or off the atoms, giv­ing them an electrical charge.

Electricity exists everywhere, but is so well balanced,
that you seldom notice it. But, sometimes differences
in electrical charges build up between materials, and
sparks can fly. Lightning is the same effect as the
sparks between clothes, but on a much greater scale.
A cloud holds static electricity just like a sweater.

Photo courtesy of: NOAA Photo Library, NOAA Central Library;
OAR/ERL/National Severe Storms Laboratory (NSSL) [via pingnews].

Why do
you often “see”
lightning before

you “hear” it? It is

because light trav-

els faster than

sound.

+

+

+

+

+

Electrons

–

–

–

–

–

–

Nucleus

This diagram shows the
structure of an atom, except
that the nucleus and elec­trons are actually much far­ther apart.

Find some clothes that cling together in
the dryer, and try to uncling them.

Rub a sweater (wool is best) and see how
it clings to other clothes.

Take off a sweater (wool is best) and listen
for crackling noises. Try it in a dark room
and see if you see sparks. Compare the
effects with different fabrics (wool, cotton,
etc.).

Note: This project works best on a cold dry day. If
the weather is humid, the water vapor in the air al­lows the static electric charge to dissipate, and this
project may not work.

If you wet the clothes then the static charge should
mostly dissipate. (Try it.)

You need a comb (or plastic ruler) and a
water faucet for this part. Run the comb
through your hair several times then hold it
next to a slow, thin stream of water from a
faucet. The water will bend towards it. You
can also use a plastic ruler. Rub it on your
clothes (wool works best).

Rubbing the comb
through your hair
builds up a static
electrical charge on
it, which attracts the
water.

-15-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 16

Next, hold your magnet near the paper pieces; nothing happens.

Run the comb in your hair again and place it next to the iron filings case; not much
happens (there may be a weak attraction). Now hold the magnet near the iron fil­ings; they jump to it easily.

What’s happening?

Iron filings are

weakly attracted

to the comb.

Iron filings are

strongly attracted

to the magnet.

Find a comb (or a plastic ruler) and some paper. Rip up the paper
into small pieces. Run the comb through your hair several times
then hold it near the paper pieces to pick them up. You can also
use a pen or plastic ruler, rub it on your clothes (wool works best).

Rubbing the comb through your hair pulls extremely tiny charged
particles from your hair onto the comb. These give the comb a
static electrical charge, which attracts the paper pieces.

Running the comb through your
hair builds up an electric charge
in it, which is different from the
magnetic charge in the magnet.
The paper pieces are attracted
to an electric charge, while the
iron filings are attracted to a
magnetic charge.

You will learn more about the
differences between electricity
and magnetism later.

Notice how your hair can “stand up” or be attracted to the comb when
the air is dry. How will this change if you wet your hair? (Try it.)

Take a piece of newspa­per or other thin paper
and rub it vigorously with
a sweater or pencil. It will
stick to a wall.

Cut the paper into two
long strips, rub them, then
hang them next to each
other. See if they attract
or repel each other.

If you have two balloons, rub
them to a sweater and then
hang the rubbed sides next
to each other. They repel
away. You could also use
the balloons to pick up tiny
pieces of paper.

Electricity is immensely more powerful than gravity (gravity is what causes
things to fall to the ground when you drop them). However electrical attrac­tion is so completely balanced out that you don’t notice it, while gravity’s ef­fects are always apparent because they are not balanced out.

Gravity is actually the attraction between objects due to their weight (or tech­nically, their mass). This effect is extremely small and can be ignored unless
one of the objects is as big as a planet (like the earth). Gravity attraction
never goes away and is seen every time you drop something. Electrical
charge, though usually balanced out perfectly, can move around and
change quickly.

For example, you have seen how clothes can cling together in the dryer due
to static electricity. There is also a gravity attraction between the sweaters,
but it is always extremely small.

-16-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 17

Project 5

Light the Way

What is really happening here?

1. The batteries (B3) convert chemical energy into
electrical energy and “push” it through the circuit,
just like the electricity from your power company. A
battery pushes electricity through a circuit just like a
pump pushes water through a pipe.

2. The snap wires (the blue pieces) carry the electricity
around the circuit, just like wires carry electricity
around your home. Wires carry electricity just like
pipes carry water.

3. The meter (M5) measures how much electricity is
flowing in a circuit, like a water meter shows how
fast water flows in a pipe.

4. The lamp (L4) converts electrical energy into light,
it is the same as a lamp in your home except
smaller. In an incandescent light bulb, electricity
heats up a high-resistance wire until it glows. A lamp
uses the energy carried by electricity, resisting its
flow like a pile of rocks resists the flow of water in a
pipe.

5. The slide switch (S1) controls the electricity by turn-
ing it on or off, just like a light switch on the wall of
your home. A switch controls electricity like a faucet
controls water.

6. The base grid is a platform for mounting the circuit,
just like how wires are mounted in the walls of your
home to control the lights.

Water Meter

Pump

Valve

Comparing Electric Flow to Water
Flow:

Touch the lamp after it has been on for
a while; it should feel it little warm (es­pecially if you cover the venting holes).
In an incandescent light bulb, only about
5% of the electricity is converted into
light, the rest becomes heat. Don’t
touch incandescent bulbs in your home
because they can be very hot.

Build the circuit shown by placing all the parts with a black 1 next
to them on the board first. Then, assemble parts marked with a

2. Install three (3) “AA” batteries (not included) into the battery
holder (B3). Set the meter (M5) to the 1A setting. Turn on the
slide switch (S1); the lamp (L4) lights and the meter measures
the current.

Placement Level Numbers

1A

-17-

Resistor

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:41 PM Page 18

-18-

Use the preceding circuit but replace the lamp (L4) with the white LED
(D6, “+” on top). Turn on the slide switch (S1); the LED lights.

Project 6

Light Bulbs of the Future

Compare the LED current (measured on the meter) to the current with the
lamp (you can also try it with the meter on the 1mA setting instead of the 1A
setting). How do they compare?

Would you rather use incandescent light bulbs or LEDs to light your home?

Notice that white LED has a “+” polarity marking, but the lamp does not.
What do you think would happen if you flipped the LED or lamp around in
this circuit? (Try it.)

LEDs are much more efficient than incandescent light bulbs and last
longer. LEDs are also more expensive, but their cost has been declining,
so LEDs are increasingly being used for home lighting.

Project 7

Ohm’s Law

Build the circuit, set the meter (M5) to the 5V setting, and turn on the slide
switch (S1). The lamp (L4) lights and the meter measures the voltage.

You can swap the location of the lamp with the 3-snap wire or slide switch in
this circuit, then measure the voltage across each of those parts and calculate
their resistance using Ohm’s law. What do you think their resistance will be?

5V

Measurements from this circuit and the project 5 circuit can be used
to measure the lamp resistance using Ohm’s Law.

1. Measure the voltage using this circuit.

2. Measure the current using the project 5 circuit (remove the 3-snap
wire, connect the meter where the 3-snap was, and set the meter to
the 1A setting).

3. Calculate the lamp resistance using Ohm’s Law:

The lamp resistance is usually 15-30 ohms, when used at 4.5V. The
other parts in the circuit (switch, meter on 1A scale, blue snap wires,
and batteries) also have resistance but these are much smaller.

Note: Your actual results may vary. Your M5 meter is a simple
meter; don’t expect it to be as accurate as normal electronic test in­struments.

You can also calculate the power of the lamp: using: Power = Voltage
x Current.
It should be about 1 watt. Compare this to incandescent light bulbs
in your home, which are usually about 40-100 watts.

Voltage

Current

Resistance =

LEDs are like one-way, low-current meters. LEDs have a “turn-on” voltage
threshold (about 3V for your white LED) that must be exceeded to turn them
on, then quickly get bright. LEDs can be made to product light in different
colors.

Answers are at www.snapcircuits.net/scstem1

.

Your
calculation:

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:42 PM Page 19

Project 8

Switches

Build the circuit, set the meter (M5) to the 5V setting, and initially set the switcher
(S6) to the middle position. Turn on each of the switches:

A. Hold the magnet near the reed switch (S9) to turn on the meter.
B. Push the press switch (S2) to turn on the white LED (D6).
C. Turn on the slide switch (S1) to turn on the left lamp (L4).
D. Set the switcher to the left position to turn on the center lamp.
E. Set the switcher to the right position to turn on the right lamp.

Name at least 10 things in your
home that use switches.

5V

Switches come in almost every shape
and size imaginable. There are mem­brane, rocker, rotary, DIP, push button,
magnetic, and momentary types just to
name a few.

The “on” position of a switch is also
called the “closed” position. Similarly, the
“off” position is also called the “open” po­sition. This is because the symbol for a
slide switch is similar to the symbol for a
door in an architect’s drawing of a room:

The electronics symbol for a simple slide
switch should be thought of as a door to
a circuit, which swings open when the
switch is off. The “door” to the circuit is
closed when the switch is on. This is
shown here:

Push Button

Computer

Keyboards

Rocker

Tools

Rotary

Selector Switch

on Appliances

Slide

Toys,

Household

Items

Walls

Door

Open Switch (turned off)

he current carrying capacity of a switch
depends on the contact material, size,
and the pressure between the contacts.

Closed Switch (turned on)

if you flip the switcher
(S6) around (as shown
below), how will it change
the circuit? (Try it.)

Note that the switcher’s connections look
like this:

-19-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:42 PM Page 20

When wires from different parts of a circuit connect
accidentally then we have a “short circuit”. A short
circuit is a wiring path that bypasses the circuit resist­ance, creating a no-resistance path across the bat­teries. It is the “easiest” path through the circuit, it is
not always the “shortest”. A short circuit will activate
the fuse in your battery holder and/or quickly drain
your batteries. Be careful not to make short circuits
when building your circuits. Always check your wiring
before turning on a circuit. See page 10 for examples
of short circuits.

Project 9

Fuse

Build the circuit, set the meter (M5) to the 1A setting, and turn on the slide switch
(S1). The lamp (L4) lights.

What do you think would happen if you push the press switch (S2) for a moment?
Try it.

What do you think would happen if you pushed the press switch for a while? Try it.
You should see the current increase, then drop down after a few seconds.

1A

Name some devices in your home that have a fuse.

Pushing the press switch bypasses the lamp, making the
meter the only resistance in the circuit. The meter has very
low resistance on its 1A setting, so there is nothing in the
circuit to limit the current. When you push the press switch,
the high current (>1A) activates a safety fuse in the battery
holder (B3) after a few seconds, which lowers the current
enough to protect the batteries and
other components from being
overloaded. The fuse shuts off
shortly after the circuit problem it
had detected is corrected. The
fuse is the small yellow component
inside the battery holder.

This wire melts to
break the circuit.

Fuses are designed to shut down a circuit when the current
is abnormally high (indicating something is wrong, such as
a component failure, bad design, or a person using it im­properly). This shutdown prevents further damage to the cir­cuit, and can prevent explosions or fires. Fuses are
important for safety and most electrical products have one,
especially if they use electricity supplied by your local elec­tric company.

Some fuses need to be replaced after they “blow”, but oth­ers can be reset by flipping a switch, and some (like the one
in your battery holder) can reset automatically. Every home
has an electrical box of resettable fuses, it may look like this:

Some fuses have spe­cial wires designed to
break when an unex­pectedly high current
flows through them.

-20-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:42 PM Page 21

Project 10

Materials Tester

If you have the build-your-own electromagnet connected to
the two-Spring socket (?1), disconnect its wires for this proj­ect. Build the circuit and set the meter (M5) to the 1A setting.

Turn on the slide switch (S1) and touch (or connect) various
materials between the springs on the two--spring socket
See which materials are good at transporting electricity by
watching the meter current and lamp (L4) brightness. Try
string, the electrodes, a shirt, plastic, paper, two of your fin­gers, wood, or anything in your home.

If the meter reads zero, switch it to the 1mA setting to see if
there is just a very small current. To help protect the meter,
always switch back to the 1A scale before testing a new cir­cuit.

1A

Which materials gave the highest reading on the meter, and
which gave the lowest?

Some materials, such as metals, have very low resistance to electricity will
make the lamp bright and give a large current measurement on the meter.
These materials are called conductors. Conductors have electrons that are
loosely held to the nucleus and can move easily.

Other materials, such as paper, air, and plastic, have very high resistance to
electricity. These will turn off the lamp and give a zero current measurement
on the meter even in the 1mA setting. These materials are called insulators.
Insulators have their electrons locked in tight and have no room for more.

The best conductor ever discovered is silver, which is very expensive. Cop­per is the second best conductor, and it is used in almost all electrical wires.

You can use Ohm’s Law to measure the resistance of the materials you
tested. The voltage is about 4.5V, and use the current measured on the meter.

Voltage
Current

Resistance =

What is Resistance? Take your hands and rub
them together very fast. Your hands should feel
warm. The friction between your hands con­verts your effort into heat. Resistance is the
electrical friction between an electric current and
the material it is flowing through; it is the loss of
energy from electrons as they move through the
material.

-21-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:42 PM Page 22

Project 11

Make Your Own Parts

Build the circuit shown, and set the meter (M5) to the 1mA setting. Make your parts using either the water puddles
method (A), the drawn parts method (B), or the pencil parts method (C), and turn on the slide switch (S1). Touch
the metal in the jumper wires to your parts and read the current in milliamps.

Part B:

Place the ends of the wires in a cup of water, making sure the metal parts aren’t touching each other. Turn on the
slide switch and read the current on the meter.

Add salt to the water and stir to dissolve it. The current should be higher now (if not already at full scale), since salt
water has less resistance than plain water.

Now add more water to the cup and watch the current.

If you have some distilled water, place the jumper wires in it and measure the current. You should measure close
to zero current, since distilled (pure) water has very high resistance. Normal water has impurities which lower its
resistance. Now add salt to the distilled water and watch the current increase as the salt dissolves!

You can also measure the current through other liquids.

Don’t drink any water or liquids used here.

Note: Depending on your local water supply, your current measurement may exceed the 1mA scale. You can switch
the meter to the 5V scale to get a better comparison, though it isn’t really a voltage measurement. (In the 5V setting,
the water resistance is compared to the internal resistance of the meter. A low reading means the water has relatively
high resistance, and a high reading means the water has relatively low resistance.)

Which gave a higher reading on the meter,
long narrow shapes or short wide shapes?

You can use Ohm’s Law to measure the resistance of
your puddles and drawings. The voltage is about 4.5V,
and use the current measured on the meter.

The black core of pencils is graphite, the same mate­rial used in resistor components throughout the elec­tronics industry.

Pure water has very high resistance because
its atoms hold their electrons tightly and have
no room for more. Impurities (such as dis­solved dirt, minerals, or salt) decrease the re­sistance because their atoms have loose
electrons, which make it easier for other elec­trons to move through.

1mA

Voltage
Current

Resistance =

Method A (easy): Spread
some water on the table
into puddles of different
shapes, perhaps like the
ones shown below. Touch
the jumper wires to points
at the ends of the puddles.

Method C (adult supervision and permission required): Change
the setting on the meter to the 1A scale. Use some double-sided pencils
if available, or VERY CAREFULLY break some pencils in half. Touch
the jumper wires to the black core of the pencil at both ends.

Method B (challenging): Use a SHARP pencil
(No. 2 lead is best) and draw shapes, such as the
ones here. Draw them on a hard, flat surface.
Press hard and fill in several times until you have a
thick, even layer of pencil lead. Touch the jumper
wires to points at the ends of the drawings. You
may get better electrical contact if you wet the metal
with a few drops of water. Wash your hands when
finished.

-22-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:42 PM Page 23

Project 12

Motor Resistance

Build the circuit, set the meter (M5) to the 1A
setting, and turn on the slide switch (S1). The
motor (M1) spins and the meter measures the
current. Do this with and without the fan on the
motor.

Calculate the resistance of the motor,
with and without the fan. How does
your calculation of the motor’s resist­ance compare with its typical resist­ance? What factors could have
caused the difference?

Calculate the power of the motor, with
and without the fan. Does the motor
use more power when the fan is on
it? Why?

The battery voltage is 4.5V, so use your current
measurements to determine the motor resistance
using Ohm’s Law.

The motor resistance is typically 5-20 ohms with
the fan and 25-100 ohms without the fan.

Note: Your actual results may vary. Your M5
meter is a simple meter; don’t expect it to be as
accurate as normal electronic test instruments.

Calculate the power of the motor using: Power =
Voltage x Current.

Voltage

Current

Resistance =

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

1A

Project 13

1A

Build the circuit, set the meter (M5) to the 1A
setting, and turn on the slide switch (S1). The
meter measures the current through the elec­tromagnet. Drop the thin rod into the electro­magnet; it will be suspended in mid-air.

Use Ohm’s Law to calculate the resistance
of the electromagnet’s resistance, and com­pare with its typical resistance.

The electromagnet is just a large coil of wire, its
resistance is about 30 ohms.

Wires can generally be as long as desired with­out affecting performance, just as using garden
hoses of different lengths has little effect on the
water pressure as you water your garden. How­ever there are cases where the length and size
of a pipe does matter, such as in the water lines
for your city. Similarly, wire length and size are
important for electric power lines transporting
electricity from a power plant in a remote area
to a city.

Electromagnet Resistance

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Project 14

Series Circuit

Build the circuit, set the meter to the 1A setting, and turn on the
slide switch (S1). The three lamps (L4) are dimly lit, and the
meter measures the current.

1A

The three lamps are connected in a series, and all the electric current from the bat­teries flows through each component in the circuit. The lamps are dim because the
voltage from the batteries (B3) is divided between them.

Connecting parts in series is one way of arranging them in a circuit. The advantage
of it is that wiring them together is simple. The disadvantage is that if one lamp
breaks, all three will be off.

How would the current change if you replaced one of the
lamps with a 3-snap wire? (Try it.)

How would the current change if you replaced two of the
lamps with 3-snap wires? (Try it.)

How would the current change if you replaced one of the
lamps with the white LED (D6)? (Try it, oriented in both di­rections.)

How will the circuit performance change if you re-arranged
the parts in the circuit? (Try it, but note that the meter and
battery holder only fit one way.)

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Project 15

Series Circuit - Voltage

This circuit is similar to the preceding one, but measures
the voltage instead of the current. Build the circuit, set the
meter to the 5V setting, and turn on the slide switch (S1).
The three lamps (L4) are dimly lit. Snap the loose end of
the red jumper wire to points A, B, C, or D to measure the
voltage at that point using the meter.

You can also connect the red jumper anywhere in the circuit
to measure the voltage there.

This circuit shows how the total voltage from the bat­teries gets divided among the components in the cir­cuit, which are resisting the flow of electricity.

In this circuit the lamps are the resistances which are
limiting the flow of electricity. Placing resistances in se­ries increases the total resistance. Advanced users
can compute the total resistance as follows:

R

series = R1 + R2 + R3 + . . .

The current is the same through all the resistances in
a series circuit. Ohm’s Law says that Voltage equals
Current times Resistance, so the highest resistances
in a series circuit will have the largest voltage drop
across them. Equal resistances will have the same
voltage drop. In other words:

Voltage =

(across one resistor)

Resistance (of that resistor)

Resistance

(total of resistors in the circuit)

x Voltage

(total applied to the

series circuit)

5V

A B C

D

How would the voltage change if you replaced one of the
lamps with a 3-snap wire? (Try it.)

How would the voltage change if you replaced one of the
lamps with the white LED (D6, “+” on the right)? (Try it.)

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Project 16

Parallel Circuit

Build the circuit, set the meter (M5) to the 1A setting, and turn
on the slide switch (S1). The lamps (L4) are bright and the
meter measures the current.

1A

How would the current change if you removed one or two
lamps? (Try it.)

How would the current change if you replaced one of the
lamps with the white LED (D6)? (Try it.)

In this circuit the batteries produce an electric current,
which flows through the meter, then divides between the
3 lamps, then re-combines and flows through the switch,
and back into the batteries.

The three lamps are connected in parallel with one an­other. They are bright because each lamp gets the full bat­tery voltage. The voltage pushes the current with equal
force, because all are 4.5V, down each path.

Most of the lights in your house are connected in parallel;
so if one bulb burns out then the others are not affected.

drawing is saved as Many Paths

Which way does electricity really flow? In
the above drawing electricity is shown flowing
from the “+” battery terminal, through the cir­cuit, and back to the “–” battery terminal. This
is how electricity was presumed to flow begin­ning with discoveries by Benjamin Franklin in

1747. Later discoveries in sub-atomic physics
showed that the charged particles that were
moving (electrons) had a “–” charge, and that
they were moving from “–” to “+” charged ma­terials.However, understanding circuits is eas­ier if you assume electricity flows from “+” to
“–”, and all circuit analysis is done this way.

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Project 17

Parallel Circuit - Voltage

Build the circuit, set the meter (M5) to the 5V setting, but leave the slide
switch (S1) off. The meter measures the voltage on the batteries. The
lamps (L4) will be off, because the switch is off.

Now turn on the slide switch to light the lamps, and see if the voltage
changes.

How would the voltage change if you replaced your batteries with ones
that are weaker or stronger? (Try it if you have different batteries avail­able.)

How would the voltage change if you left the switch (and lamps) on for
a long time?

How would the voltage change if you removed one or two lamps? (Try
it.)

How would the voltage change if you replaced one of the lamps with
the white LED (D6)? (Try it.)

Batteries produce electricity using a chemical reaction, but they have a
limited supply of the chemicals, and not all of
them can react at once. If the batteries can­not produce as much electricity as a circuit
wants, the voltage drops.

Some batteries, called rechargeable batteries (such as the batteries in
your cell phone), allow you to reverse the chemical reaction using an­other electric source.

5V

Connecting parts in parallel is another way of arranging them in a circuit.
The advantage of it is that if one burns out, the others will still work (re­move one of the lamps to prove this). The disadvantage is that wiring
the parts together is more complex than with series circuits.

All large circuits are made of combinations of series and parallel circuits.

In this circuit the lamps are the resistances which are limiting the flow of
electricity. Placing resistances in parallel decreases the total resistance.
Advanced users can compute the total resistance as follows:

The voltage is the same across all the resistances in a parallel circuit.
Ohm’s Law says that Voltage equals Current times Resistance, so the
lowest resistances in a parallel circuit will have the most current through
them. Equal resistances will have the same current. In other words:

Current (through one branch) =

Resistance

(total in all OTHER parallel branches)

Resistance

(total of resistors in all branches)

x Current (total applied to the parallel circuit)

1 1 1 1

= + + + . . . .

Rparallel R1 R2 R3

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Project 18

Parallel Swapping

Build the main circuit and set the meter (M5) on the 5V setting.
Turn on the slide switch (S1); the lamp (L4) lights and the meter
(M5) measures the voltage from the batteries (B3).

Part B: move the meter so it’s across location “B” and then location
“C”. Measure the voltage at each location, is it the same?

Part C: swap the locations of the meter and lamp. Does the meter
still measure the same voltage?

This circuit shows that rearranging parts that are
connected in parallel does not change the circuit,
because the meter measured the same voltage
for each arrangement.

5V

Part B

Part C

B

C

Give some examples of parallel circuits in your home.

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Project 19

Series Swapping

Build the main circuit and set the meter (M5) on the 1A setting.
Turn on the slide switch (S1); the lamps (L4) light dimly and the
meter (M5) measures the current through the circuit.

Now swap the positions of any of the lamps, 3-snap wires, the
slide switch and the meter (the meter should always be placed
so it hangs out of the circuit). Read the current on the meter; does
it read the same for each arrangement?

When you turn on the switch, does the meter measure a higher
current initially than it does after a few seconds? Why?

Note: Your M5 meter is a simple meter. It may read zero on this
scale even though a small current is flowing.

1A

Examples

In the first moment after you press
the switch, the meter will show a
higher “surge” current. Light bulbs
have less resistance when you
first turn them on, then increase
resistance as they get bright.

The order of parts connected in series or in parallel does not matter ­what matters is how combinations of these sub-circuits are arranged
together.

The choice of whether to use a series or parallel configuration in a cir­cuit depends on the application, but will usually be obvious. For ex­ample the overhead lights in the rooms of your home are all connected
in parallel so that you can have lights on in some rooms and off in oth­ers, but within each room the light and switch are connected in series
so the switch can control the light.

Give some examples of series circuits in your home.

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Part CPart B

Project 20

Batteries in Series

Build the circuit, set the meter (M5) to the 5V setting, and turn on the slide switch (S1).

Part A: Read the battery voltage on the meter. If your batteries are new then it should
be about 4.5V.

Part B: Remove the left battery in the holder (B3) and move the end of the red jumper
wire to touch the left spring in the holder. Read the voltage on the meter; measuring 2
batteries.

Part C: Now also remove the center battery and move the end of the red jumper wire
to touch the center spring in the holder. Read the voltage on the meter; measuring 1
battery.

NOTE: The accuracy of your meter may vary.

What voltage did you measure in Part A?

What voltage did you measure in Part B?

What voltage did you measure in Part C?

5V

When batteries are connected in series, they add together, making
the total voltage higher. An AA type battery is rated at 1.5V, but
brand new ones will be up to 1.6V, and they get weaker as they
are used up.

In Part A, the battery holder (B3) has three 1.5V type AA batteries
in series, so the battery voltage is about 4.5V (1.5V + 1.5V + 1.5V
= 4.5V).

In Part B, you are measuring two 1.5V type AA batteries in series,
so the voltage is about 3V (1.5V + 1.5V = 3V).

In part C, you are measuring one 1.5V type AA battery, so the volt­age is about 1.5V.

Part A

Use the preceding circuit, but replace the
meter (M5) with the lamp (L4). Compare the
lamp brightness with 3 batteries (Part A), 2
batteries (Part B), or 1 battery (Part C).

Does the lamp brightness change like the
voltage does (are they proportional)?

Your L4 lamp is designed to be
used at 4.5V; lower voltages like

1.5V or 3V do not get the bulb’s
filament hot enough to produce
light as well. See project 29 for
further explanation of this.

Project 21

Lamp at Different Voltages

If a circuit is given too much voltage
then its components will be damaged.
It is like having the water in your faucet
come out at higher pressure than you
need, and it splashes all over the
room. If water in a pipe is at too high
of pressure then the pipe may burst.

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Use the preceding circuit, but replace the lamp (L4) with the motor
(M1, “+” on top), with or without the fan. Compare the motor speed
with 3 batteries (Part A), 2 batteries (Part B), or 1 battery (Part C).
Try it with the fan and without the fan.

Does the motor speed change like the voltage does (are they proportional)?

Project 22

Motor at Different Voltages

Use the preceding circuit, but
replace the motor (M1), with
the white LED (D6, “+” on
top). Compare the LED bright­ness with 3 batteries (Part A),
2 batteries (Part B), or 1 bat­tery (Part C). The LED may
not light with 1 or 2 batteries.

Does the LED brightness change like the voltage does (are they proportional)?

Project 23

LED at Different Voltages

LEDs have a turn-on voltage thresh­old that must be exceeded before the
LED produces any light, then bright­ness increases quickly. The LED’s
threshold depends on the LED color
and characteristics but is typically

1.5V for red LEDs, and about 3V for
white LEDs.

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean
over the motor.

Project 24

Voltage Shifter

With both lamps on, what is the voltage measured across
the top lamp?

With both lamps on, what do you think the voltage across
the bottom lamp is? Swap the locations of the meter and
press switch to see if you are right, then swap them back.

With the press switch pushed, what is the voltage meas­ured across the top lamp?

Is it double the voltage measured across the top lamp
when both lamps were on?

Why did the voltage change?

Is the top lamp brighter now?

Build the circuit, and set the meter (M5) to the
5V setting. Turn on the slide switch (S1); the
lamps (L4) are on and the meter measures the
voltage across the top lamp. Push the press
switch (S2) to turn off the bottom lamp.

One of the most basic rules for ana­lyzing circuits is Kirchhoff’s Voltage
Law: the total voltage driving a circuit
must equal the voltage drops within it.

This project proves it because the total
voltage across both lamps equals the
voltage from the batteries: (Vbatteries =
Vlamp1 + Vlamp2)

Since the battery voltage driving the
circuit is the same, bypassing the bot­tom lamp shifts all the voltage to the
top lamp. This follows Kirchhoff’s Volt­age Law.

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Project 25

Double Voltage Shifter

This project is similar to the preceding one, but uses three lamps. Build
the circuit, and set the meter (M5) to the 5V setting. The lamps (L4) are
on dimly and the meter measures the voltage across the top lamp. Push
the press switch (S2) to turn off the bottom lamp. Turn on the slide switch
(S1) to turn off the middle lamp. Disconnect the battery holder when you
are finished with this project.

The voltage you measure with only one lamp on should be double the
voltage with two lamps on, and triple the voltage with three lamps on.
The voltage divides evenly, because the lamps all have the same char­acteristics.

This is another example of how voltage divides as parts are added in
series. The lamps are acting as resistors, because they limit the flow of
electricity in the circuit. As resistances are added in series, they add to­gether to reduce the current.

With all three lamps on (both switches off), what is the voltage meas­ured across the top lamp?

With all lamps on, what do you think the voltage across each other
lamp is? Swap the location of the meter with either switch to see if
you are right, then swap them back.

Turn on one or both switches, and compare the voltage measured
with one, two, or all three lamps on.

Why did the voltage change?

5V

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Project 26

Double Switching Ammeter

This project is similar to the preceding one, but measures current instead
of voltage. Build the circuit, and set the meter (M5) to the 1A setting. The
lamps (L4) are on dimly and the meter measures the current through the
circuit. Push the press switch (S2) to turn off the bottom lamp. Turn on
the slide switch (S1) to turn off the middle lamp. Compare the current
with one, two, or all three lamps on. Disconnect the battery holder when
you are finished with this project.

This circuit is an example of how current
decreases as parts are added in series. If
more than one lamp is on, the voltage
from the batteries is split among them, and
less current will flow through the circuit.

In theory the current with one lamp on
should be twice as much as when two
lamps are on and triple as much as when
three lamps are on, but your results will be
different because incandescent lamps like
these have more resistance when they are
brighter, and because your M5 meter is a
simple meter with limited accuracy.

With all three lamps on (both switches off), what is the current?

Turn on one or both switches, and compare the current measured with
one, two, or all three lamps on.

Why did the current change?

1A

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Project 27

Current Divider

The current from the batteries splits up between the
three lamps, because they are connected in parallel.
Connecting parts in parallel allows more current to
flow, so it decreases the overall circuit resistance.

If you add up the current you measured through circuit
branches B, C, and D, it should be the same as the
current you measured from the batteries. (Your result
may be a little different, because M5 is a simple meter
with limited accuracy.)

Kirchhoff’s Current Law, an important rule for ana­lyzing circuits, says that all current flowing into a point
must flow out of it.

(Current

batteries

= Current

lampB

+ Current

lampC

+ Current

LampD

)

Are the currents through circuit branches B, C, and D the same or different?

Add up the currents through circuit branches B, C, and D. How does the total
compare to the main circuit current (part A)?

1A

B C

D

Part B

Part C

Part D

Part A: Build the main circuit, and set

the meter (M5) to the 1A setting. Turn
on the slide switch (S1); the lamps
(L4) are all bright and the meter
measures the current through the cir­cuit.

Part B: Swap the location of the
meter with the 3-snap wire marked “B”
(“+” side towards the lamp). The
meter shows the current through cir­cuit branch “B”.

Part C: Swap the “B” location of the
meter with the “C” 3-snap. The meter
shows the current through circuit
branch “C”.

PartD: Swap the “C” location of the
meter with the “D” 3-snap. The meter
shows the current through circuit
branch “D”.

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Project 28

3 Currents

Build the main circuit, and set the meter (M5) to the 1A set­ting. Push the press switch (S2), turn on the slide switch (S1),
or set the switcher to the top position (turning it on). Turn on
the switches one at a time and in combinations, comparing
the current on the meter.

Project 29

AND Circuit

Place the magnet next to the reed
switch (S9) to turn it on, push the
press switch (S2), and turn on the
slide switch (S1) in different combina­tions while seeing if the lamp (L4)
lights. Fill out this table with the re­sults:

Are the three switches connected in series or in parallel?

Give an example of an AND circuit in your home.

If switch S9, switch S1, AND
switch S2 are on then the lamp
will be on. Engineers refer to this
switching combination as an
AND sub-circuit (short for “this
AND that”).

Having to turn on several
switches just to turn on a lamp
seems simple but is very im­portant. The press switch
could represent an on/off
switch on an electric saw, one
of the slide switches could be
a safety switch on the saw,
and the reed switch could be
a fuse box in your basement.
Safety is very important in
electrical wiring.

S9 S1 S2 L4

OFF OFF OFF

OFF OFF ON

OFF ON OFF

OFF ON ON

ON OFF OFF

ON OFF ON

ON ON OFF

ON ON ON

1A

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Project 31

Light Bulb

Build the circuit. Turn on the
slide switch (S1) on and off
several times, watching the
brightness of each lamp
(L4). Compare the bright­ness of each lamp, and
how quickly each turns on.

All the electric current flows through the right lamp, then divides between the two lamps
on the left. The right lamp is much brighter than the others because it has twice as much
electricity flowing through it, but that is not the only reason for the difference in brightness.

Why is the top lamp so much brighter than the others, even though it only has twice as
much electricity through it? And why do the left bulbs take a few seconds before they make
any light?

This happens because a dim light bulb has less resistance than a bright one. Incandescent
bulbs like these make light by passing a big electric current through a special high-resis­tance wire, the filament. The high current heats up the filament, which gets so hot that it
glows. The left bulbs get less current than the top one so they take longer to heat up and
don’t get as hot, barely getting hot enough to light their filaments.

How much brighter is the right lamp compared to
the others?

Why do the two lamps on the left turn on
slowly?

Project 30

OR Circuit

if switch S9, switch S1 OR switch S2
is on then the lamp will be on. Engi­neers refer to this

switching combi­nation as an OR sub-circuit (short
for “this OR that”). The same type
of circuit is used throughout your
home, such as having several
sensors controlling a security light.

Place the magnet next to the reed switch
(S9) to turn it on, push the press switch
(S2), and turn on the slide switch (S1) in
different combinations while seeing if the
lamp (L4) lights. Fill out this table with
the results:

S9 S1 S2 L4

OFF OFF OFF

OFF OFF ON

OFF ON OFF

OFF ON ON

ON OFF OFF

ON OFF ON

ON ON OFF

ON ON ON

Are the three switches connected in series or in parallel?

Give an example of an OR circuit in your home.

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Project 32

Light Bulb with Meter

This circuit is like the preceding one, but
adds a meter so you can compare the volt­ages across the lamps. Build the circuit, set
the meter (M5) to the 5V setting, and turn on
the slide switch (S1). The meter measures
the voltage across the top lamp, which is
bright.

Part B: Move the meter so it is across the
lower lamps, as shown. Now the meter meas­ure the voltage across the lower lamps, which
are very dim. Watch the lower lamps and the
meter closely; initially the lamps are dark, but
slowly become dimly lit.

Note: The voltage in Part B will be much
smaller; in some cases it may even be too
small to measure with your M5 meter. M5
is a simple meter, don’t expect it to be as ac­curate as normal electronic test instruments.

Part B

What is the voltage across the top lamp?

What is the voltage across the lower lamps?

Remove the top 3-snap wire (which connects
to the battery holder) and place the meter
there. Set the meter to the 1A setting and
measure the circuit current.

With the above measurements, use Ohm’s Law
( ) to calculate the resistance of the lamps:

Find a fluorescent or LED bulb and feel the heat
coming off it; you won’t feel much. Find an incan­descent lamp THAT HAS BEEN OFF FOR A
WHILE and turn it on. Feel the heat it produces;
it soon becomes too hot to touch. How much hot­ter is the incandescent bulb?

5V

The resistance of the lower lamps is typically
about triple that of the top lamp, but your re­sults may vary. All wires have higher resist­ance when they are very hot.

Incandescent bulbs produce lots of heat, and
the glass bulb prevents the filament from react­ing with oxygen in the air and burning. When
the voltage rating of an incandescent bulb is ex­ceeded, the filament gets so hot it burns out.
Filaments are usually made of tungsten, since
ordinary copper would melt.

Most of the electrical energy used by incan­descent light bulbs becomes heat, not light.

Only about 5% of the electricity used by incan­descent bulbs is converted into light. Without
the more efficient fluorescent bulbs (and in­creasingly LEDs bulbs), our society of office
buildings might have been much different.

Resistance (top lamp) =

Voltage

(top lamp)

Current

(as measured)

Resistance (each lower lamp) =

Voltage

(lower lamps)

half of Current

(since split between 2 lamps)

=

=

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Project 33

2 Direction Motor

Build the circuit. Set the switcher (S6) to the
middle position (off), set the meter (M5) to the
1A setting, and place the fan on the motor (M1).
Now set the switcher to the top position; the
motor spins, the lamp (L4) lights, and the meter
measures the current. Set the switcher back to
the middle position to turn off the circuit.

The switcher is used to reverse the
battery connections (from snap A &
D) to snaps B & C, which reverses
the voltage across the motor and
lamp. In the top position, battery “+”
is connected to snap B, and in the
bottom position battery “+” is con­nected to snap C.

Study the circuit. What will happen to the motor, lamp, and meter if
you change the switcher to the bottom position? (Try it.)

1A

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean
over the motor.

The switcher’s connections look
like this:

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Project 34

3-Speed Motor

Build the circuit, set the switcher (S6) to the middle position (off), set the
meter (M5) to the 1A setting, and leave the fan off the motor (M1). Push
switch (S2); the motor spins, and the meter measures the current. Turn
on the slide switch (S1) or set the switcher to the left position to adjust
the motor speed. You may need to give the motor a push to get it started,
but do not touch it while it is spinning. Sometimes the lamps may not
light.

Here you control the motor
speed by diverting some of
the current to the lamps.

When S1 and S6 are off the top lamp
should be dim or off, why?

1A

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean
over the motor.

Now place the fan on the motor. Turn on the slide switch and set the
switcher to the left (so both switches are on), and push the press switch.
The motor will not spin.

Now turn off the slide switch and set the switcher to the middle position
(so both switches are off), push S2 to get the motor spinning, then set
the slide switches back (so both are on) while still pushing S2.

Note: Motor performance may vary, in rare cases it may spin in all switch
settings.

The motor could not start spinning with the other lamps on, but it
will keep spinning as long as you keep pushing S2. Why?

The surfaces touched by the motor
shaft offer some resistance to motion,
called friction. Once the initial friction
is overcome, it doesn’t take much ef­fort to keep the motor spinning. This
is especially important when the
motor is trying to start the fan, due to
the fan weight.

+

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Project 35

3-Speed Motor - Voltage

This circuit is just like the preceding one, except the meter measures the voltage instead of
the current. Build the circuit, set the switcher (S6) to the middle position (off), set the meter
(M5) to the 5V setting, and leave the fan off the motor (M1). Push switch (S2); the motor
spins, and the meter measures the voltage. Turn on the slide switch (S1) or set the switcher
to the right position to adjust the motor speed. You may need to give the motor a push to
get it started, but do not touch it while it is spinning. Sometimes the lamps may not light.

Now place the fan on the motor and try the different switch combinations again.

Turning on the other lamps diverts
current away from the motor, re­ducing the voltage across it and
slowing it down.

Compare the voltage measurements with out the fan to those with the fan.

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

5V

+

Project 36

3-Speed Motor with Fan

Build the circuit, set the switcher (S6) to the middle position (off), set the meter
(M5) to the 1A setting, and place the fan on the motor (M1). Push switch (S2);
the motor spins, and the meter measures the current. Turn on the slide switch
(S1) or set the switcher to the right position to adjust the motor speed. You may
need to give the motor a push to get it started, but do not touch it while it is spin­ning. Sometimes the lamps may not light.

Turn on the slide switch and set the switcher to the right (so both
switches are on), and push the press switch to get the fan spin­ning fast. Now turn off the slide switch and watch how long it
takes to light the middle lamp; how long does it take to light, and
why?

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

+

1A

-40-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 41

1A

+

Build the circuit, set the switcher (S6) to the middle position (off), set the meter (M5) to the
1A setting, and place the fan on the motor (M1). First, set the switcher to the left position to
start the motor. Then turn on the slide switch (S1) to increase the speed. Then push the
press switch (S2) to increase the speed again. Then hold the magnet next to the reed switch
(S9) to turn it on, further increasing the motor speed. Try different combinations of those
switches. The meter measures the current.

Project 37

4-Speed Motor

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

Project 38

Back EMF

Build the circuit as shown, leave the fan off the motor (M1).

Place your finger on the top of the motor shaft to prevent it from spinning, then
push the press switch (S2) - the lamps (L4) are bright. Now release the motor shaft
and press the switch again - the lamps get dim or go out as the motor speeds up.
DO NOT TOUCH THE MOTOR WHILE IT SPINS.

Next, place the fan on the motor and push the press switch again - the lamps
stay bright as the fan speeds up.

+

The voltage from the batteries (B3) pushes an electric current through a coil in the motor,
which spins the shaft using magnetism. But the spinning shaft also uses magnetism to
produce a current in the coil, which opposes the current from the batteries.

The result is that the motor has low resistance when the shaft isn’t spinning fast, allowing
a higher current to make the lamps bright. When the shaft is spinning really fast without
the fan, the motor has high resistance, limiting the current and keeping the lamps dim.

The voltage/current produced by a motor when it is spinning is called its Back Electro-
Motive-Force (Back EMF); this may be thought of as the motor’s electrical resistance.
The motor’s Front Electro-Motive-Force is the force it exerts in trying to spin the shaft.
This circuit demonstrates how the Back EMF increases and the overall current decreases
as the motor speeds up.

Why does the fan affect the lamp brightness?

-41-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 42

Project 39

Big Load

Build the circuit, set the switcher (S6) to the middle or lower position (off),
set the meter (M5) to the 1A setting, and place the fan on the motor (M1).
Set the switcher to the top position to light the lamps (L4), push the press
switch (S2) to spin the motor, and turn on the slide switch (S1) to light
the white LED (D6). Try each switch separately and in different combi­nations, and compare the current measured on the meter.

Remove the fan from the motor
and compare the current. Why is
it higher or lower?

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean
over the motor.

+

1A

Project 40

Big Load - Voltage

Use the preceding circuit but replace the meter (M5) with a 3-snap wire,
then set the meter to the 5V setting and place it across the battery holder,
as shown. With all the switches off, the meter measures the battery volt­age. Turn on the switches to light the lights and spin the motor, compar­ing how much the voltage changes for each. If available, compare
different batteries (such as old and new, or alkaline and non-alkaline) to
see how much the voltage changes.

Using this and the preceding circuit, compare the current and voltage
for each switch. Does the voltage drop more when the current is higher?

+

5V

The higher the current, the more
the lights and motor are “loading”
the batteries, making the batteries
work harder. Removing the fan
from the motor makes the motor
shaft easier to spin, lightening its
load.

The battery voltage (electrical pressure) may drop as
the current increases, because the batteries may not be
able to supply all the current the circuit needs. This ef­fect is more noticeable when the batteries are weaker.

-42-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 43

5V

+

Part B

5V

Project 41

Holding Down

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

Build the circuit. Set the meter (M5) to the 5V
scale, place the fan on the motor (M1), and drop
the thin rod into the electromagnet (M3).

Turn on the slide switch (S1). The fan spins, the
lamps (L4) light, and the meter measures the
voltage. Nothing happens to the thin rod. No­tice that the voltage is much lower then the nor­mal 4.5V; the motor and lamps are overloading
the batteries (B3), so the voltage drops.

Part B: Turn off the circuit, remove the motor
and lamps, then turn the circuit back on. Now
the measured voltage is much higher, and the
thin rod gets sucked up by the electromagnet.

The motor and lamps overloaded
the batteries and prevented the
electromagnet from sucking up
the thin rod.

How do you think the measured voltage in the top circuit would be affected if you added 100 more
lamps to the circuit?

-43-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 44

Switching circuits like this are commonly used to
control motors in products like remote-controlled
cars. Electronic controlled transistors are used in
place of the switches, and the motor drives the
wheels in the car.

Project 42

Propellor and Fan

Build the circuit as shown, and set the switcher (S6) to the mid­dle position at first, then set it to the bottom position to spin the
fan. The fan blades suck in air around the motor (M1) and push
it straight up. Hold a sheet of paper above the motor, it will get
pushed up and away from the fan.

Flip the switcher to the top position now. The fan spins the
other direction and sucks in air from above and pushes it down
to the table. If the fan is spinning fast enough, then it will rise
into the air when you turn off the switcher (sometimes it may
fly off sooner due to vibrations). If you hold a sheet of paper
near the motor, it will get sucked into the fan. If the fan doesn’t
fly off, then turn the switcher on and off several times rapidly
when it is at full speed.

+

How does electricity turn the shaft in the motor? The answer is
magnetism. The motor is the opposite of an electromagnet. Moving
a magnet near a coil of wire can make a current flow in it (like the
electromagnet), but a current flowing can move a magnet.

Inside the motor is a coil of wire mounted on a shaft. The motor shell
has a magnet on it. When electricity flows through the coil of wire,
it repels from the magnet on the motor shell and the shaft spins. If
the fan is on the motor shaft then its blades will create airflow.

Magnet

Shaft

Power Contacts

Shell

To prove the motor has a magnet inside, move your compass
around it. The red needle will be attracted to one side but re­pelled from the other.

Motors are used throughout our society to convert
electricity into mechanical motion.

Coil

When the motor is blowing air up, it is a fan - just
like the ones in your home. It will cool you off on
a hot day.

When the motor is sucking air in, it is a propeller

- just like the ones on helicopters or small air­planes.

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

-44-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 45

Build the circuit, set the meter (M5) to the 5V scale, and turn on the slide
switch (S1). The meter measures the voltage across the white LED (D6)
and motor (M1). Notice how fast the fan spins, and how bright the lights
are. The lamps (L4) may be off.

Remove one lamp and compare the motor speed and brightness of the
lights. Then remove a second lamp and compare again.

Lastly, turn off the switch, remove the fan from the motor, then turn the
switch back on and compare the voltage measured and brightness of
the lights. Do this with one, two, or three lamps in the circuit.

Project 43

Motor & Lights

5V

+

The electromagnet (M3) has
a lot more resistance than the
lamps (L4).

Modify the preceding circuit to be this one. Keep the meter (M5) on the
5V scale. Turn on the slide switch (S1), then push the press switch (S2)
if the white LED (D6) is off or the motor (M1) is not spinning. Compare
the results to the preceding circuit. Try it with and without the fan on the
motor.

Project 44

Slow Motor & Lights

5V

+

With three lamps, the current
through each may not be
high enough to make its fila­ment hot enough to glow.

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING: Do not

lean over the motor.

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING: Do not

lean over the motor.

-45-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 46

1 3

2 4

Refrigerator

Door

Project 45

Compass

1. Hold your compass away from everything,
notice that the red arrow always points
north. Spin it around, the red arrow will
adjust and resume pointing north.

The earth’s core is made of iron, which has
a magnetic field. The compass points north
because it is attracted to this magnetic
field. This allows compasses to be used for
navigation.

2. Now place the compass next to a large
iron object, such as a refrigerator or car.
If the object is heavy enough, the red
arrow will point toward it.

Large iron objects also exert a small mag­netic field, which may attract a nearby
compass. The magnetic field is much
weaker than the earth’s, but much closer
to the compass.

3. Now place your magnet near the com­pass. The red arrow will immediately
point toward the black “S” side of the
magnet, ignoring a nearby refrigerator.

Magnets have been induced to have a
concentrated magnetic field at either end.
This magnetic field is much stronger than
ordinary iron objects that may be nearby.

4. Tie the magnet to a string and hold it near
the compass. Gently spin the magnet,
and see how the compass needle moves.

5. Pull out a 2-snap wire, a paper clip, the
electrodes, the iron core rod, and the thin
bar. Decide which of these you think the
magnet will pick up, then try it and see if
you were right. Do the same for other ma­terials in your home.

The physical properties of iron make it
easy to induce a magnetic attraction in.
This doesn’t work for other metals or other
materials.

All materials have tiny particles with
electric charges, but these are so well
balanced that you do not notice them
unless an outside voltage disturbs
them. The same tiny particles also
have magnetic charges, which are usu­ally so well balanced that you do not
notice them unless a magnetic field dis­turbs them.

Magnets are materials that concentrate
their magnetic charges at opposite
ends. One side attracts while the other
repels, but the overall material is neu­tral. Most magnets are made of iron.

The name “magnet” comes from mag­netite, an iron ore that magnetism was
first seen in.

The earth we live on is a giant magnet,
due to its iron core. A compass needle
always points north because it is at­tracted to the earth’s magnetic field.
The opposite ends of a magnet are
often labeled north and south, repre­senting the north and south poles of the
earth. A compass actually points to the
earth’s magnetic north pole (which is in
the Arctic Ocean just north of Canada),
not the geographic north pole.

5

-46-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 47

1

4

2

3

1.

There is an area around a magnet where it can affect other objects, called a magnetic field. It is
strongest at the ends of the magnet.

2. Slowly move your compass around the magnet and watch its pointer to see the magnetic field.

3. Shake the iron filings pack to spread the filings evenly. Move the magnet over the filings and
you can see the magnetic field in them.

4. Loop two paper clips together. Hold them near the magnet and move them around it to see the
magnetic field.

Project 46

Magnetic Fields

A magnet has a magnetic field, and a bat­tery has an electric field. The north and
south poles of a magnet are comparable
to the positive and negative terminals of
a battery.

Electric and magnetic fields affect each
other. If you place a magnet next to a
radio your reception can be disturbed.

Magnet - magnetic field

Battery - electric field

Permanent magnets are made
by exposing iron (or other met­als) to a much stronger mag­netic field, usually from an
electromagnet.

Magnets can
magnetize other materials
(usually iron), concentrating
their magnetic charges at op­posite ends. This causes the
magnetic attraction/ repulsion

that you see. Magnetization
can be temporary or long-last­ing, depending on the materi­als and magnetic force used.
For example, Paper Clips at­tracted to a magnet some­times stick together after the
magnet is removed. Most
magnets can be demagnet­ized using heat or vibration.

Name some items that use magnets:

-47-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 48

Iron Core Rod

Rubber Grommet

Project 47

Electronic Magnet

Build the circuit shown. Place the iron core rod inside the
electromagnet (M3) and secure it with the rubber grommet.
This project works best if you have new alkaline batteries.

Hold the electromagnet near something made of iron and
push the switch (S2). While pressed, the electromagnet
will attract small metal parts like nails or will stick to a ham­mer or refrigerator. Release the switch and the attraction
disappears.

Pressing the switch turns on an electric cur­rent which transforms the electromagnet from
an ordinary coil of copper wire into a magnet.
An electronic magnet is much better than an
ordinary magnet because you can turn it on
or off with a switch!

An electron current flowing in a wire has a tiny
magnetic field. By looping a long wire into a
coil the tiny magnetic field is concentrated into
a large one.

The strength of the magnetic field
depends on how much current is flowing in
the wire and how many loops of wire.

Names some advantages and disadvantages of electronic
magnets compared to permanent magnets.

-48-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 49

Iron Core Rod

Rubber Grommet

1

2

3

4

You can turn on the switch to
pick up things with the electro­magnet, then release the switch
to drop them. This is done with
large magnets at factories or
junk yards.

Project 48

Electromagnet Magnetic Field

1. Use the circuit from the preceding project, with the
iron core rod in the electromagnet (M3). An elec­tronic magnet has a magnetic field just like an or­dinary magnet. Hold your compass next to the
electromagnet and push the press switch (S2).
Move the compass all around the electromagnet
and watch where the compass points.

2. The magnetic field created by a magnet occurs in
a loop. You can see this using paper clips.

3. Remove the iron core rod from the electromagnet.
Now push the press switch again and try to pick
up things with the electromagnet. The attraction
is now very weak.

The iron core rod concentrated the magnetic ef­fects of the electromagnet. You can use the com­pass to see that electronic field is now much
weaker.

4. Materials made of iron concentrate their magnetic
effects at both ends. The center of the material
is magnetically neutral because the attraction
from each end is the same.

The magnetic field created by the electromagnet
works the same way. It is strongest at both ends
but neutral in the center. But the electromagnet
is hollow - so iron at one end will be sucked into
the middle.

Lay the electromagnet on its side. Hold the thin
rod next to the center hole and push the press
switch to suck it inside. Hold the switch and gently
pull the rod to see how much suction the electro­magnet has.

The compass needle
maypoint opposite to how
it’s shown here, depend­ing on how you connected
the jumper wires.

-49-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 50

Project 49

Electromagnet Tower

Coils of wire store energy in a magnetic field,
while static electricity stores energy in an elec­tric charge across a material (an electric field).

Magnets concentrate their magnetic effects at
both ends. The magnetic field is strongest at
both ends but neutral in the center, because
the attraction from each end is the same. But
the electromagnet is hollow - so iron at one
end will be sucked into the middle.

The magnetic field produced by the electro­magnet has direction just like a normal mag­net. Opposite ends of magnets attract, while
like ends repel each other.

Find two magnets in your home. Try putting
them together, then flip one around. They will
attract one way but repel the other way.

Build the circuit as shown and drop the thin rod into
the electromagnet (M3).

Push the press switch (S2)
several times. The thin rod gets sucked into the
electromagnet and can be suspended there, or you
can bounce it up and down.

When you push the press switch, the thin rod gets
sucked up and wiggles up and down until settling
in position just below center. Measure how high
you get the thin rod to go, then try with old and
brand new batteries. Remove a 1-snap from under
each side of the electromagnet, then see how high
the thin rod will go.

Part B: With the switch pressed and the thin rod
suspended in mid-air, hold the magnet near the
thin rod. Notice that the red (N) side of the magnet
repels the thin rod but the black (S) side attracts it.

Note: the magnet poles may be opposite of how it’s
shown here, depending on how you connected the
electromagnet (M3).

-50-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:43 PM Page 51

The direction of a magnetic
field from a current flowing in
a wire (or coil of wire) de­pends on the direction of the
electric current.

Project 50

Electromagnet Direction

Build the circuit shown. Place the iron core rod in the electromagnet (M3), and set the meter (M5) to the
1A scale. Set the switcher (S6) to the top or bottom position.

The meter shows a current is flowing

and the compass needle is attracted to the electromagnet.

Now set the switcher to the opposite side (left or right). The other side of the compass needed
is attracted to the electromagnet (magnetic field is reversed). In some cases you may need
to hold the compass closer to the electromagnet for the needle to change sides.

If you remove the iron core rod from the electromagnet, the compass needle attraction will
be much weaker. Try moving the rod in and out while watching the compass.

1A

Project 51

Wire Magnet

Build the circuit as shown. Note that the 5-snap wire is connected on level 4 on the left side
and at level 3 on the right side, over the compass; make sure it is securely snapped. This circuit
works best with new alkaline batteries. Keep the circuit away from any iron objects.

Turn on the slide switch (S1) and switch the switcher (S6) between the top and bottom positions
repeatedly while watching the compass. You should see the compass needle move a little - in­dicating a change in the magnetic field from the 5-snap wire (the “wire magnet”“).

Note: The magnetic field produced by the wire is very small. If the compass needle does not
move, check your batteries (B3) and make sure you are not close to any iron objects.

The three lamps (L4) are in this circuit to
limit the current; without them the circuit
would have almost no resistance (since
the only components would be switches
and wires). Then the “wire magnet”
would have a stronger magnetic field,
but the higher current would trigger a
safety fuse in your battery holder, which
would quickly shut down the circuit.

Any electric current flowing in
a wire has a magnetic field,
but it is usually very small. An
electromagnet creates a no­ticeable magnetic field by
looping the wire very many
times to concentrate the
magnetic field from it.

-51-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 52

FOR ADVANCED USERS - ADULT SUPERVISION RECOMMENDED

Rubber Grommet

Iron Core Rod

Part B

This circuit shows how wrapping a wire into a coil concen­trates the magnetic field from the wire. The more loops of
wire a coil has, the stronger the magnetic field produced. So
if you only loop the jumper wire around the iron core rod a
few times, the magnetic field will not be nearly as strong. You
can also see how looping the wire around an iron core in­creases the magnetic field produced.

Your M3 electromag­net is just like the coiled red wire except that it has many
more loops, giving it a stronger magnetic field.

Project 52

Better Wire Magnet

Build the circuit. Place the rubber grommet on one end of the iron core rod
and wrap the red jumper wire tightly around it, as shown. Connect the red
jumper wire to the circuit.

Turn on the slide switch (S1) and set the switcher (S6) to the top or bottom
position.

Move the iron core rod (with the red wire around it) around the compass

and watch how it attracts the compass needle.

Switch the switcher between the top and bottom positions

and watch the com-

pass to see how the magnetic field has changed.

Part B: Now take off the rubber grommet and remove the iron core rod, but
keep the red wire wound in a coil and connected to the circuit. Push the press
switch and watch the compass while moving the coiled red wire around it.
Now the compass needle has much less attraction to the red wire.

How could you make this electromagnet more powerful?

-52-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 53

The wire magnet in the preceding circuit is not very powerful because it only has
a few loops of wire, but you can make a better one. Assemble the build-your-own
electromagnet (the thin wire wrapped around an iron core rod, with the ends con­nected to the 2-spring socket (?1)) using the instructions on page 5.

Connect the build-your-own electromagnet to the preceding circuit as shown here.
Turn on the slide switch (S1) and set the switcher (S6) to the top or bottom posi­tion. Move the compass around the build-your-own electromagnet and watch how
its needle is attracted.

Switch the switcher between the top and bottom positions

and watch the compass

to see how the magnetic field has changed.

Project 53

Build-Your-Own Electromagnet

How does the build-your-own electromagnet used here compare with the wire
magnet used in the preceding project? Which is more powerful?

How does it compare to the M3 electromagnet used in project 49?

Project 54

Build-Your-Own Electromagnet (II)

Use the preceding circuit. Connect several paperclips into a chain
and hold near the build-your-own electromagnet, studying the at­traction. See if the electromagnet can pick up paperclips. Lay the
iron fillings case on top of your electromagnet and change the
magnetic field using the switcher (S6).

Your can also try these tests with the wire magnet from project

52.

-53-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 54

B

1mA

Project 55

Magnetic Induction

The meter shows an electric current even though no batteries are used. By mov­ing the magnet near the coil, you have induced (created) a current in the circuit.
You have made electricity from magnetism - an electric generator! This simple
concept is very important to our society. High pressure water from dams or steam
(often heated by burning oil or coal) spins large magnets in coils to produce much
of the electricity that runs our cities.

Project 56

Electromagnetic Induction

A

Build the circuit as shown. Assemble the build-your­own electromagnet as per the instructions on page

5. Push the wire on the build-your-own electromagnet
to one side and insert its iron rod into the top of the
electromagnet (M3), as shown.

Push the press switch (S2) and watch the white LED
(D6) when you press or release the switch; you
should see a flash. The flash on the LED is easier to
see if you look directly into the LED and block the
light from the lamps with your hand. If you don’t see
any flash on the LED then you may need to push the
iron rod further into the M3 electromagnet.

Pull the iron rod out the M3 electromagnet. The LED
should no longer light when you press the switch, be­cause the magnetic connection between the circuits
is broken now.

You can replace the build-your-own electromagnet

with the one made with the red jumper wire in project
52 (wind the red wire on one side of the rod), but it
will not work as well because it has less windings.

You can also replace the white LED with the meter
(M5, on the 1mA setting).

Notice that this only works when the magnetic field is
changing due to you pressing or releasing the switch.
If you keep the switch pressed the magnetic field is
constant, and no current is induced in the electro­magnet to light the LED.

Note: The lamps (L4) are in the circuit to limit the cur­rent through the build-your-own electromagnet. If you
replace one of the lamps with a 3-snap wire then the
LED may flash a little brighter, but you should only
press the switch briefly because pressing it makes a
short circuit and may activate the fuse (see project 9
for more details).

Build the circuit as shown. Place the iron core rod into the electromagnet (M3) and set the meter
(M5) to the 1mA scale.

A. Move the magnet left-right or up-down near the electromagnet. You may see the meter pointer

wiggle, which indicates a small current.

B. Place the magnet on the iron core rod and use it to move the rod up and down IN the electro-

magnet. The meter pointer should move or wiggle slightly, showing a current is produced.

Try removing the iron core rod from the electromagnet and see how the current is affected.

If you have a more powerful magnet in your home, use it in place of the Snap Circuits

®

STEM magnet.

A more powerful magnet will create a larger current and be easier to measure.

-54-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 55

Project 57

Electromagnet Challenge

Assemble the build-your-own electromagnet
(the thin wire wrapped around an iron core rod,
with the ends connected to the 2-spring socket
(?1)) using the instructions on page 5. Build the
circuit, place the iron core rod in the electromag­net (M3).

Set the switcher (S6) to the left position to turn
on the build-your-own electromagnet, set it to
the right position to turn on the M3 electromag­net, or set it to the middle position to turn off the
circuit. Move the compass around to compare
the magnetic fields from the two electromagnets.
Connect several paperclips into a chain and hold
near each electromagnet, comparing them.

To turn on both electromagnets at the same
time, connect a 3-snap wire between the 2­spring socket and the M3 electromagnet (over
the switcher), and set the switcher to either the
left or right position.

This circuit isn’t really a fair
comparison between the
build-your-own and M3 elec­tromagnets, because the
build-your-own electromag­net is in series with the
lamps (L4). The lamps limit
the current through the
build-your-own electromag­net (to avoid triggering the
safety fuse), but also lower
its power. The M3 electro­magnet has enough resist­ance to avoid triggering the
safety fuse.

Project 58

Coil Resistance

Build the circuit shown and set the meter (M5) to
the 5V setting. Set the switcher (S6) to the bottom
position; the meter shows that the full battery volt­age is across the white LED (D6, and the LED is
very bright.

Now set the switcher to the top position to place
the electromagnet (M3) and relay (S3) in series
with the white LED. The voltage is a little lower
now, and the LED is not as bright.

Next, replace the white LED with a lamp (L4). Com­pare the difference in lamp brightness with the
switcher in the top and bottom positions.

The wire in the coils of the
electromagnet and relay is
long enough to have no­ticeable resistance; this re­sistance makes the white
LED a little less bright, and
prevents the lamp from
lighting at all.

5V

-55-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 56

5V

1A

or

!

WARNING: Moving parts. Do not

touch the fan or motor during operation.

!

WARNING: Do not lean over the motor.

Project 59

Generator

SET THE SWITCHER (S6) TO THE MIDDLE POSITION BEFORE COMPLET­ING THE CIRCUIT. Build the circuit as shown, leave the fan off the motor (M1).
Set the meter (M5) to the 5V scale for now.

Set the switcher to the right position to get the motor spinning, then set it to the
left position and watch the meter to see how much voltage is produced.

Next, set the meter to the 1A scale and set the switcher to the right  for a few
seconds, then set it to the left and watch the current produced.

Part B: Put the fan on the motor and repeat the above tests to see what volt­age and current are produced with the fan on the motor.

+

This circuit uses the batteries (B3) to get the motor spinning, then disconnects
the batteries and uses the motor as a generator. A generator uses mechan­ical motion (here the spinning motor shaft) to create electricity (a current in a
coil in the motor). The meter shows how much current and voltage are pro­duced by the spinning shaft, with and without the fan.

Compare the electrical energy produced by the generator (the motor): Is the
voltage higher with or without the fan?

Is the current higher with or without the fan?

Does the voltage/current last longer with or without the fan?

Add the white LED (D6) to the preceding circuit, as shown.
Set the switcher to the right to get the motor spinning, then
set it to the left and watch the white LED. Do it both with and
without the fan on the motor, comparing the light from the
LED.

Project 60

Generator with Light

If you replace the white LED with the lamp (L4), how bright
will the lamp get? (Try it, both with and without the fan.)

5V

1A

or

The white LED needs about 3V to turn
on, so should get bright without the
fan, but may not light at all with the fan.
The lamp needs a sustained high cur­rent to heat up its filament enough to
produce light.

-56-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 57

Magnet

Coil of Wire

Water Flow

Gears are used between two wheels or shafts. One wheel spins at
low speed but with great force, while the other wheel spins at high
speed but with much less force. This can increase efficiency or give
greater control.

Project 62

Make Your Own Generator

+

1mA

Build the circuit and set the
meter (M5) to the 1mA scale.
Spin the motor (M1) top clock­wise with your fingers and watch
how much current is produced.
(Clockwise means in the direc­tion in which the hands of a
clock rotate.)

Now spin the motor in the other
direction (counter-clockwise).
You won’t see much current pro­duced now because it is pro­duced in the other direction - the
meter needs to be flipped
around. Instead of flipping the
meter around, flip the motor
around to see this.

Name some products in your home that
have a generator.

This circuit is a true generator, using mo­tion (and magnetism) to make an electric
current.In electric power plants, the same
thing happens but on a much larger scale.
High-pressure steam or water spins a
shaft, which uses magnetism to make an
electric current in a coil of wire.

Notice that this circuit used the 1mA
meter setting while the preceding circuit
used the 1A setting (1000 times greater).
You can produce a much higher current
by spinning the shaft much faster.

Hand-cranked generators like this are
used in some flashlights instead of batter­ies. They use gears to spin the shaft
much faster.

Project 61

Motor with Flashes

Build the circuit shown and watch the white
LED (D6) as you push and release the
press switch (S2). Notice that even though
the LED is connected backwards, it is flash­ing dimly while the fan is spinning, and then
flashes brightly when you release the press
switch.

You can also try this without the fan, or hold­ing the motor top so it can’t spin (but don’t
touch the motor top while it is spinning).

!

WARNING: Moving parts. Do not

touch the fan during operation.

As the motor shafts spins it pro­duces small voltage spikes (both
positive and negative), which can
be enough to dimly light the LED.

When you release the switch (turn­ing off power to the motor), a mag­netic field in it collapses, releasing
energy that lights the white LED.

+

!

WARNING:

Do not lean over the motor.

-57-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 58

Project 63

FOR ADVANCED USERS - ADULT SUPERVISION RECOMMENDED

High Speed Generator

+

1mA

Build the circuit and set the meter (M5) to the 1mA scale.
Using the string, make a small loop at one end and put it on a
prong of the motor (M1) top. Wind a few feet of the string
around the motor shaft (wind it so that pulling the string will
spin the motor shaft clockwise).

Pull the string gently but fast, watching the white LED (D6) and
the current produced in the meter. If you wind the string well
and pull it fast, you can briefly light the LED. Get an adult to
help with this if needed.

The LED will light more easily if you remove the meter and
connect the LED where the meter was.

A spare motor top is included with this kit in case you break
any of the prongs on the motor top. Use a screwdriver to pry
off the broken piece, then push the new one on.

This circuit shows how much more current is
produced when you spin the motor shaft faster.

Project 64

Magnetic Energy Released

When you release the switch (turning off power to
the electromagnet), the magnetic field collapses,
releasing energy that lights the white LED. The
magnetic field is stronger when the iron core rod
is in the electromagnet. There is also a small flash
in the LED when the circuit is turned on, setting
up the magnetic field.

Build the circuit, and place the iron core rod into the elec­tromagnet (M3). Push and release the press switch (S2)
while watching the white LED (D6). Try it with and without
the iron core rod in the electromagnet.

How bright will the white LED flash if you remove the 2-snap
wire from the circuit (to disconnect the electromagnet? (Try it.)

4

2

3

-58-

1

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 59

Project 65

Relay Magnetic Energy Released

Build the circuit, then push and release
the press switch (S2) while watching
the white LED (D6).

The relay (S3) has a coil with a mag­netic field, just like the electromagnet
(M3). The lamp does not have a coil or
a magnetic field. so the white LED will
not light with the lamp in the circuit.

Replace the relay (S3) with the lamp (L4). Does the white LED flash?

Project 66

Reed Switch

The reed switch is an electrical switch that can be
controlled by a magnet. It has two metal contacts
close together inside a glass tube. The magnetic
field from the magnet makes the contacts come
together, completing a circuit just like other
switches do.

Place the magnet next to the reed switch (S9) to
activate it, turning on the lights (D6 & L4).

What could you use a reed switch for?

-59-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 60

Project 67

Reed Switch with Electromagnet

Build the circuit as shown, and turn on the slide switch (S1). The electromagnet (M3)
should be activating the reed switch (S9), which turns on the white LED (D6). Raise
the iron core rod in the electromagnet (or remove the rod) to turn off the LED.

You can also remove the electromagnet and instead connect it to the circuit using the
red & black jumper wires, then hold it near the reed switch to turn on the LED.

Project 68

Build-Your-Own Reed Switch

Build the circuit as shown. There are three 2-snap wires at base grid locations
A1-B1. Snap the 6-snap wire at base grid location F5, then place it so it lays
on the snap at grid location B2 (DO NOT SNAP IT ON). A 3-snap wire is
placed across grid locations B1-B3, with the left side on lever 4 and the right
side on level 3; sure it is securely snapped. Place the nut snap on the 6-snap
wire.

Turn on the slide switch (S1); the top lamp (L4) lights.

Now hold the magnet just above the nut snap to attract it; this should turn off
the top lamp. Use the magnet to raise the 6-snap wire until its loose end con­tacts the bottom of the 3-snap wire, which should turn on the bottom lamp.

Moving the magnet up and down above the nut snap should attract and re­lease it, raising and lowering the 6-snap wire, flipping the lamps on and off.

Reed switches are used as proximity switches and in door and window
sensors for burglar alarms. Speed sensors on bicycles use a reed switch
to detect when a magnet on the wheel passes the sensor.

-60-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 61

Project 69

Relay

Build the circuit and turn on the slide switch (S1); the lamp
(L4) is on. Now push the press switch (S2) to activate the
relay (S3); you hear a click as the relay switches power
from the lamp to the white LED (D6).

You can replace the white LED with the motor (M1) and fan
if you like.

With the press switch off, the relay is
off, so the 1 and 2 contacts are on
the relay are connected, and current
flows through the lamp.

With the press switch on, current
flows through a coil in the relay,
which magnetically switches the
relay’s contacts. Now the relay’s 1
and 3 contacts are connected, and
current instead flows through the
white LED.

The current through the press switch activates the coil in the relay, which
changes the relay connection from contacts 1-2 to contacts 1-3. There is no elec­trical connection between the relay’s coil and 1-2-3 contacts, so those circuits do
not affect each other, and can operate at different voltages. In this way a low­voltage circuit can control a high-voltage or high-current circuit.

Most industrial machinery and home appliances operate at voltages of 120V or
higher. However, the circuits used to control them (either automatically or by in­terfacing with people) operate at low voltages. These voltages are usually less
than 6V and very rarely higher than 50V. Relays allow these low voltage devices
to control high voltage machinery and appliances.

List some devices in your home that use relays.

What is the main reason to use a relay?

Relays use magnetism to open or
close a mechanical switch. Look at
the relay symbol in the drawing.
The relay contains a coil, and a set
of contacts that are switched when
the coil is activated.

Coil

Contacts 1-3:

Coil is off: 1-2 connected
Coil is on: 1-3 connected

Relays are electronically controlled switches, which allow a low-voltage circuit
to control a high-voltage or high-current circuit.

-61-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 62

What will happen if you remove the 2-snap wire that
connects the points marked A & B, and instead con­nected the red jumper wire between points B & C?
(Try it.)

Project 70

Relay Buzzer

Build the circuit and turn on the slide switch (S1).
The relay (S3) makes a buzzing sound.

The sound is caused by the relay’s con­tacts opening and closing at a fast rate.
Look at the “1-2-3” marking on the relay
symbol in the drawing. What’s happen­ing is this: when the switch is turned on,
current flows through the relay’s coil,
causing contact 1 to disconnect from
contact 2 and connect to contact 3.
This opens the circuit and stops current
from flowing through the coil, which
causes contact 1 to move back to con­tact 2. This closes the circuit and cur­rent flows through the coil again, and
the cycle repeats continuously.

A B

C

Project 71

Relay Buzzer Meter

This circuit is similar to the preceding one, but adds the meter (M5) to measure the current.
Set the meter to the 1mA setting. Set the switcher (S6) to the right position to turn the relay
(S3) on, set the switcher to the left position to make the relay turn on and off continuously
(producing a buzzing sound), and set the switcher to the middle position to turn the circuit
off. Compare the meter current for each switcher position. The lamp (L4) will not light.

The current is actually more than 1mA (about 50mA
when the relay is on continuously), but the lamp is
used here to adjust the current to be within the 1mA
range on the meter. To see the actual current, remove
the lamp and set the meter to the 1A setting; it should
be slightly above 0.

Why is the meter current lower when the relay is buzzing?

Use Ohm’s Law (Resistance = Voltage / Current) to determine the resistance of the relay’s
coil when the relay is on continuously. The voltage is about 4.5V, and see Snappy’s note
about the meter current. (The resistance should be 50-100 ohms, but your results will vary
due to the limited accuracy of your meter, and the battery voltage may not be exactly 4.5V.)

1mA

-62-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 63

Project 73

Super Buzzer

Build the circuit as shown, and turn on the slide
switch (S1); you may hear a buzzing sound as the
relay (S3) turns on and off rapidly. Adjust the
sound by pushing the press switch (S3), raising
and lowering the iron core rod in the electromag­net (M3), or by placing the magnet near the reed
switch (S9) to activate it and the white LED (D6);
try combinations of these and see how the sound
changes.

Project 72

Alternating Voltage

Build the circuit as shown (leave the fan off the motor), and turn
on the slide switch (S1); you hear a buzzing sound as the relay
(S3) turns on and off rapidly. Set the switcher (S6) to the top or
bottom position to turn on the motor (M1) and white LED (D6).

The electricity supplied to your home and school by your local
electric company is not a constant voltage like that from a bat­tery. It averages about 120V but is constantly changing, due
to the design of the generators that produce it. This is not a
problem, since all equipment that uses it accounts for this
change. Its frequency is 60 Hz.

An electrical current that is changing is called an alternating
current, or AC. Because of this, the power from the electric
company is also called AC power. An electrical signal that is
constant and unchanging is called a direct current, or DC.
The power from a battery is also called DC power.

In project 85 and others the LED only works in one of the switcher
(S6) settings, but in this circuit it works in either the top or bottom
S6 setting. Why?

-63-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:44 PM Page 64

Project 74 Transformer

Build the circuit as shown. Assemble the build-your-own electromagnet
as per the instructions on page 5. Push the wire on the build-your-own
electromagnet to one side and insert its iron rod into the top of the elec­tromagnet (M3), as shown. Set the meter (M5) to the 1mA setting.

Push the press switch (S2) and hold it down for a few seconds; the
relay (S3) makes a buzzing sound as its contacts open and close
quickly. Watch the white LED (D6) and meter, then reverse the direc­tions of the LED and meter and push the switch again (it works better
in one direction, depending on how you wired the build-your-own elec­tromagnet). If the LED does not light in either position then you may
need to push the iron rod further into the M3 electromagnet.

Pull the iron rod out the M3 electromagnet. The LED should no longer
light when you press the switch, because the magnetic connection be­tween the circuits is broken now.

You can replace the build-your-own electromagnet with the one made
with the red jumper wire in project 52 (wind the red wire on one side of
the rod), but it will not work as well because it has less windings.

If a current through a coil can
magnetize an iron bar, what if you
had another coil from a different
circuit wrapped around the same
iron bar? The magnetization of the
iron bar would create a current in
the other circuit. This is a trans-
former, which allows one circuit
to create a current in another cir­cuit using magnetic fields.

Transformers allow circuits to be
isolated from each
other, since the con­nection between them
is magnetic and not
electrical. Transform-
ers can also change
the voltage by using
coils with more or less loops of
wire.

When electric power companies
transport electricity across great
distances (like between power
generating plants and cities), they
use very high voltages and low
currents since this reduces power
loss in the wires. Large trans­formers convert this to 120V,

which is supplied to homes and
offices. Many products (like com­puters) then use small transform­ers to convert this to smaller or
larger voltages as needed.

A transformer is a magnetic
bridge, since we use magnetism
to cross an air gap that electricity
cannot cross by itself.

Iron Bar

Created
Current

Original Current

High Voltage
Power Lines

Transformer

120V House

Power Line

Power Plant

Typical

Transformer

1mA

The buzzing sound produced by
the relay is used to create a con­stantly changing magnetic field in
the build-your-own electromagnet,
which induces a current in the M3
electromagnet, which is seen on
the LED and meter.

-64-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 65

Project 76

Relay Circuit

Build the circuit, place the glow fan on the motor (M1), and set the meter
(M5) to the 1A setting. Turn on the slide switch (S1); the three lamps (L4)
light and the meter measures the current.

Push the press switch (S2) to activate the relay (S3). The lamps turn off
and the motor (M1) spins the fan.

1A

Name an appliance in your home that uses a relay to switch lights or mo­tors on and off.

Project 75

Relay Memory

Build the circuit and turn on
the slide switch (S1). Noth­ing happens. Now push the
press switch (S2). The lamp
(L4) comes on and stays on
even after you release the
press switch (the circuit “re­members” that you pushed
the press switch). Turn off
the slide switch to turn off
the lamp.

Why is the lamp off until you push the press switch?

Why does the lamp stay on after you release the
press switch? (Look at the explanation of how the
relay works in project 8, and note that when the relay
is on contacts 1 and 3 on the relay symbol in the draw­ing are connected.)

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean
over the motor.

+

-65-

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FOR ADVANCED USERS - ADULT SUPERVISION RECOMMENDED

Note spring

direction of

1-snap

Project 77

Build Your Own Relay

Build the circuit shown. Three 3-snaps are stacked together
at base grid location E4-E6. Snap the 4-snap onto the 1­snap at grid location D2, then place it so it lays on the snap
at F4 (DO NOT SNAP IT ON). Place the nut-snap on the 4­snap so it will be under the electromagnet (M3). This circuit
works best with new alkaline batteries.

Place the rubber grommet on the iron core rod and push the
rod into the electromagnet until it is just barely above the
nut-snap without touching it (0.025 inches).

Turn on the slide switch (S1). The lamp (L4) should be on
(if off, make sure the 4-snap is touching the 2-snap at F4
without being snapped there).

Push the press switch (S2) to turn on the electromagnet.
This should raise the 4-snap slightly and turn off the lamp
(adjust the position of the grommet on the rod if it does not).
If you still can’t get it to work, rotate the 1-snap at location
D2 to the proper spring direction as shown, this may make
the 4-snap move more easily.

The current through the electromagnet
makes a magnetic field that attracts the
nut-snap, which breaks the circuit to the
lamp.

-66-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 67

FOR ADVANCED USERS -

ADULT SUPERVISION RECOMMENDED

Note spring

direction of

1-snap

Project 78

Build Your Own Buzzer

As in the preceding relay circuits, the current
through the electromagnet makes a magnetic
field that attracts the nut-snap, which breaks the
circuit to the lamp. However in this circuit attract­ing the nut-snap also breaks the circuit to the
electromagnet, which then releases the nut-snap.
This creates a feedback loop which raises and re­leases the nut-snap in a repeating cycle. The
buzzing sound you hear is from raising and re­leasing the nut-snap many times a second.

Build the circuit shown. At base grid location B6-B8, 3-snaps are
on levels 1, 3 and 4. Snap the 4-snap onto the 1-snap at A4, then
place it so it lays on the snap at C6 (DO NOT SNAP IT ON). Snap
the nut-snap on the 4-snap so it will be under the electromagnet
(M3). This circuit works best with new alkaline batteries.

Place the rubber grommet on the iron core rod and push the rod
into the electromagnet until it is just barely above the nut-snap
without touching it (0.025 inches).

Turn on the slide switch (S1). The lamp (L4) should be on; adjust
the position of the grommet until you hear a buzzing sound. If the
lamp is off, make sure the 4-snap is touching the lamp snap at C6
without being snapped there. Make sure the 4-snap lays centered
on the snap at C6 (vibration tends to move it off-center).

This circuit requires precise adjustment; if it doesn’t work then
make sure the grommet and 4-snap are positioned as described
above and start over. If you still can’t get it to work, rotate the 1­snap at location A4 by 90 degrees, this may make the 4-snap
move more easily.

Project 79

Build Your Own

Vibrating Circuit

Use the preceding circuit, but replace the lamp (L4) with the meter
(M5), set to the 5V scale. Since the circuit is sometimes on and
sometimes off, the meter pointer will be vibrating.

-67-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 68

1mA

You can buy a cola-powered clock.

Project 80

Cola Power

Set the meter (M5) to the 1mA scale and
connect the jumper wires to it. Connect the
other ends of the jumper wires to the snap
electrodes (red to copper), and place them
in a cup of cola soda.

Read the current on the meter. You may
switch the meter to the 5V scale to also
measure the voltage produced, but the
voltage may be too small to measure ac­curately with a simple meter like M5.

Try replacing the cola with other flavors
and compare them.

Throw away the soda used in this project.
Wash off the electrodes.

Cola-flavored soda is lightly
acidic.The acid is similar to
the material used in some
types of batteries, though
not nearly as strong.

The acid in the cola will
react with the copper and
zinc electrodes to make an
electric current, just like the
AA batteries or the larger
battery in your family car. As
some of the acid in the soda
is neutralized, the current
produced drops.

Project 81

Fruit Power

1mA

Squish or roll a lemon a few times to break up some of the cells inside
(tomatoes or grapefruit also work). Stick the copper and zinc snap elec­trodes into the lemon. Set the meter (M5) to the 1mA scale and connect
the jumper wires to it, then connect the other ends of the jumper wires to
the snap electrodes (red to copper).

Read the current from your “lemon battery” on the meter. Try placing
the electrodes in different parts of the lemon to see how the current
changes. You may switch the meter to the 5V scale to also measure
the voltage produced, but the voltage may be too small to measure ac­curately with a simple meter like M5. You may see the current/voltage
slowly drop as the “lemon battery” is used up.

If you don’t measure any current, move the electrodes closer together
or to a different place on the fruit.

Replace the lemon with other fruits or vegetables such as a tomato,
grapefruit, orange, carrot, or onion; see how much current they produce.

Throw away the fruits and vegetables when you are finished with this
project. Wash off the electrodes.

-68-

Some fruits and vegetables have a sour taste
because they are lightly acidic. The acid in
them is similar to the material used in some
types of batteries, though not nearly as strong.

The acid in the fruit will react with the copper
and zinc electrodes to make an electric cur­rent. As some of the acid in the fruit is neu­tralized, the current produced drops.

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 69

1mA

Set the meter (M5) to the 1mA scale and connect the jumper wires to it.

Connect the

other ends of the jumper wires to the snap electrodes (red to copper)

, and place them in a

cup of water.

Read the current on the meter, if it is zero then your water is relatively free of impurities.
Having impurities does not mean your water is unsafe to drink. You can try dissolving
salt in the water and see if the current changes.

If you have some distilled water, test it. It should have zero current.

Replace the water with fruit juices and see how they compare. Sour tasting juices like
lemon or grapefruit juice usually produce the most current.

Don’t drink any water or juice used in this project. Wash any juice off the electrodes.

Project 82

Water Impurity Detector

The water in some areas is slightly acidic
due to impurities in it. This may be strong
enough to produce a current by reacting
with the electrodes, similar to how a bat­tery works. These impurities should be
safe to drink.

Some fruit juices are more acidic and will
produce a higher current.

-69-

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Project 83

Swing the Magnet

Build the circuit shown and place
the iron core rod in the electro­magnet (M3). Tie the magnet to a
string and hold it just above the
electromagnet, so that the magnet
is attracted to the iron core rod
without touching it. Flip the
switcher (S6) back and forth be­tween its top and bottom positions
to reverse the electromagnet’s
magnetic field; the magnet flip
around each time.

Part A: Use the preceding circuit. Secure the paper
clip-string with a weight above the circuit, as shown.
Set the switcher (S6) to the top or bottom position to
pull the paper clip towards the electromagnet. Attract
and release the paper clip using the switcher (top and
bottom positions are on, middle position is off).

Part B: Secure the magnet in place with nothing be­neath it. Tie a paper clip to the string and place it on
the magnet. Slowly pull the string away so the paper
clip is suspended in air. Hold the paper clip in place
with a weight, as shown.

Next, hold the magnet near the paper clip and lift it
off the ground, without it touching the magnet. Move
it around in mid-air.

Project 84

Magic Rope Trick

-70-

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Morse Code: The forerunner of today’s
telephone system was the telegraph,
which was widely used in the latter half
of the 19th century. It only had two
states - on or off (that is, transmitting or
not transmitting), and could not send the
range of frequencies contained in human
voices or music. A code was developed
to send information over long distances
using this system and a sequence of
dots and dashes (short or long transmit
bursts). It was named Morse Code after
its inventor. It was also used extensively
in the early days of radio communica­tions, though it isn’t in wide use today. It
is sometimes referred to in Hollywood
movies, especially Westerns.

A . _
B _ . . .
C _ . _ .
D _ . .
E .
F . . _ .
G _ _ .

H . . . .

I . .
J . _ _ _
K _ . _
L . _ . .
M _ _

N _ .
O _ _ _
P . _ _ .
Q _ _ . _
R . _ .
S . . .
T _
U . . _
V . . . _
W . _ _
X _ . . _
Y _ . _ _
Z _ _ . .

Period

. _ . _ . _

Comma

_ _ . . _ _
Question . . _ _ . .
1 . _ _ _ _
2 . . _ _ _
3 . . . _ _

4 . . . . _

5 . . . . .

6 _ . . . .

7 _ _ . . .
8 _ _ _ . .
9 _ _ _ _ .
0 _ _ _ _ _

MORSE CODE

Project 85

Morse Code

This simple circuit can be used for communication.

Push the press switch (S2) in long and short bursts to make a pattern of light flashes rep­resenting the dots and dashes shown in the Morse Code table shown. You can use Morse
Code and this circuit to send secret messages to some friends in the room without others
knowing what you’re saying.

If you have a strong flashlight or searchlight then you can send messages to friends far
away at night. During World War II Navy ships sometimes communicated by flashing
Morse Code messages between ships using searchlights (because radio transmissions
might reveal their presence to the enemy).

Decode this Morse Code message:

. . . . . . _ . . . _ _ . _ _ .

-71-

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Project 86

Hypnotic Discs

Part A

Build the circuit as shown. Cut out the red spiral pattern shown and tape it on the
fan. Spin the pattern by briefly pushing the press switch (S2). You will see the
most interesting effects when the pattern is spinning slowly.

Part B

Replace the pattern with the colored lines pattern shown. When the switch is
pressed, the arcs turn into colored rings with a black background. Notice how the
color drops when it is stretched to make a complete circle.

Part C

Place the circuit under a fluorescent light with a T12 bulb (1.5” diameter) that runs
on normal house current. and spin the disc slowly. As the speed changes, you
may notice the lines first seem to move in one direction, then they start moving in
another direction. This effect is because the lights are blinking 120 times a second
and the changing speed of the motor is acting like a strobe light to catch the motion
at certain speeds.

+

!

WARNING: Moving parts. Do not

touch the fan or motor during operation.

!

WARNING: Do not

lean over the motor.

-72-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 73

+

Use the preceding circuit. Using the fan as a guide, draw a circle on a piece of cardboard
or paper. Cut the circle out with scissors and tape it to the fan blade so it can be easily
removed later. Obtain some thin and thick marking pens to use as drawing tools.

Spin the paper by pressing and holding the press switch (S2) down. Gently press the
marker on the paper to form rings. To make spiral drawings, release the press switch and
as the motor approaches a slow speed, move the marker from the inside outward quickly.

Change the colors often and avoid using too much black to get hypnotic effects. Another
method is to make colorful shapes on the disc then spin the disc and watch them blend
into each other.

Spin Draw is an old toy that your parents may have played with when they were young.

Project 87

Spin Draw

-73-

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Project 88

2-Way Circuit

Build the circuit, set the meter (M5) to the 1A setting, place the iron core
rod in the electromagnet (M3), and place the fan on the motor (M1). Set the
switcher (S6) to the left or right to make electricity flow through the lights,
motor, and electromagnet in opposite directions. The compass measures
the magnetic field from the electromagnet and the meter measures the cur­rent from the batteries. Set the switcher to the middle position to shut off
the circuit.

A lamp is connected in series with the motor to slow down the motor; if you
replace the lamp with a 3-snap wire then the fan may fly off.

For each component, select how they work when the electricity is reversed:

LED: A. 1 direction only B. effects unchanged C. effects reversed

Lamp: A. 1 direction only B. effects unchanged C. effects reversed

Motor: A. 1 direction only B. effects unchanged C. effects reversed

Electromagnet: A. 1 direction only B. effects unchanged C. effects reversed

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean
over the motor.

1A

Project 89

Electromagnet Music

Build the circuit, set the meter (M5) to the
5V setting, and turn on the slide switch
(S1); you hear a buzzing sound as the
relay (S3) turns on and off rapidly. Adjust
the sound by raising and lowering the iron
core rod to different heights in the electro­magnet (M3), to make music. The meter
shows how the voltage is changing.

5V

-74-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 75

Project 91

Electromagnetic Playground

Build the circuit, set the meter (M5) to the 1A setting, place
the iron core rod in the electromagnet (M3), and place the
fan on the motor (M1). Turn on the slide switch (S1); the
white LED (D6) lights, the meter measures the current, and
the electromagnet attracts the compass needle. Set the
switcher (S6) to the left to the left to light the lamps, to the
right to spin the motor & fan, or the middle to do neither.

1A

Project 90

Electromagnetic Controlled Switch

Build the circuit, place the iron core rod in the electromagnet (M3), and
turn on the slide switch (S1). Use the red & black jumper wires to hold
the reed switch (S9) over the electromagnet to turn on the lamp (L4).
You can also activate the reed switch by holding the magnet close to it.

+

-75-

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 76

Project 93

Circuits Fun

Build the circuit as shown, set the meter (M5) to the
1A setting, and place the magnet as shown. Turn
on the slide switch (S1); the white LED (D6) lights
and the meter measures the current. Set the
switcher (S6) to the top position to make the fan
spin, set it to the bottom position to make the fan
spin faster, or set it to the middle position to turn off
the fan. The compass is attached to the magnet;
push the press switch (S2) to make the compass be
attracted to the electromagnet (M3).

1A

!

WARNING: Moving parts. Do not

touch the fan during operation.

!

WARNING:

Do not lean over the motor.

Project 92

Magnetic Switcher

Build the circuit and turn on the slide switch (S1); the lamp (L4) should
be on. Hold the magnet near the reed switch (S9) to activate the relay
(S3), which turns the white LED (D6) on and the lamp off.

-76-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 77

1.

Electric current is the movement of sub­atomic charged particles through a ma­terial due to electrical pressure across
the material.

TRUE or FALSE?

2.

Voltage is a measure of the electrical pres­sure to push electric current through a cir­cuit.

TRUE or FALSE?

3. Voltage is measured in watts.
TRUE or FALSE?

4.

An advantage of electricity is that it makes it
easier to transport energy over distances.

TRUE or FALSE?

5. Resistance can be thought of as elec­trical friction, resisting the flow of elec­tricity through a circuit.

TRUE or FALSE?

6.

Resistance is measured in ohms.
TRUE or FALSE?

7. Resistance is calculated as voltage di­vided by current.

TRUE or FALSE?

8. Electrical Power is a measure of how
fast energy is moving through a wire.

TRUE or FALSE?

9. When clothes cling together in the
dryer, it is because they have an elec­tric current flowing through them.

TRUE or FALSE?

10.A switch turns a circuit on or off by con­necting or disconnecting wires in a cir­cuit.

TRUE or FALSE?

11.Batteries produce electricity using a bio­logical or nuclear reaction.

TRUE or FALSE?

12.The electric current from a battery is al­ternating current.

TRUE or FALSE?

13.A short circuit is better than a normal
circuit because it takes up less space.

TRUE or FALSE?

14.A fuse shuts down a circuit if the current
is abnormally high.

TRUE or FALSE?

15.Insulators have very low resistance to
the flow of electricity.

TRUE or FALSE?

16.An incandescent light bulb makes light
by heating a filament to be glowing hot.

TRUE or FALSE?

17.Incandescent light bulbs are more en­ergy efficient than LED bulbs.

TRUE or FALSE?

18

.An incandescent light bulb filament has

more resistance when it is cold than when
it is hot.

TRUE or FALSE?

19.

When several lamps are connected in

series, if one burns out then the oth­ers will still light.

TRUE or FALSE?

20. The two basic ways of connecting parts
in a circuit are in series and in parallel; all
large circuits are made of combinations
of these.

TRUE or FALSE?

21. In a parallel circuit, the circuit branch with
the lowest resistance will have the most
current flowing through it.

TRUE or FALSE?

22. If you want a switch to turn a lamp on and
off, you should connect the switch and
lamp in parallel.

TRUE or FALSE?

23. The voltage is the same across all com­ponents that are connected in parallel.

TRUE or FALSE?

24. An LED works the same when con­nected in either direction.

TRUE or FALSE?

25. The current through an LED is always
proportional to the voltage across it.

TRUE or FALSE?

26. Connecting several batteries in series re­duces the total voltage.

TRUE or FALSE?

27. Connecting several components in
parallel increases the total resistance.

TRUE or FALSE?

28. Reducing the resistance of a circuit will
reduce the current through it.

TRUE or FALSE?

29. When several components are wired in
series with each other, all will have the
same electric current flowing through
them.

TRUE or FALSE?

30. Reversing the current to an electro­magnet does not change the direction
of its magnetic field.

TRUE or FALSE?

31.

If a battery cannot supply as much
current as a circuit needs, the volt­age produced drops.

TRUE or FALSE?

32. The faster a motor’s shaft is spinning,
the higher its electrical resistance.

TRUE or FALSE?

33.

A motor has the same electrical resist­ance when its shaft turns in either direc­tion.

TRUE or FALSE?

34. Decreasing the number of windings in an
electromagnet increases the power of its
magnetic field.

TRUE or FALSE?

35. Electricity and magnetism do not affect
each other.

TRUE or FALSE?

36. A small electric current flowing in a wire
has a magnetic field.

TRUE or FALSE?

37. The magnetic field of a magnet is
weakest at the ends of the magnet.

TRUE or FALSE?

38.

Most magnets are made of copper.
TRUE or FALSE?

39. Placing an iron rod inside a coil of wire
with an electric current through it in­creases the magnetic field produced.

TRUE or FALSE?

40.

You can reverse the direction of the magnetic
field from an electromagnet by reversing the
direction of the electric current through it.

TRUE or FALSE?

41. If you want to be able to turn a magnetic
field on and off, you should use an elec­tronic magnet instead of an ordinary
magnet.

TRUE or FALSE?

42. An electronic magnet stores energy in
an electric field.

TRUE or FALSE?

43. In a generator, electricity is used to pro­duce mechanical motion.

TRUE or FALSE?

44. It takes more energy to spin the motor
shaft when the fan is not on it.

TRUE or FALSE?

45. A reed switch is a magnetic switch con­trolled by an electric current.

TRUE or FALSE?

46. Distilled water can power a clock better
than cola soda.

TRUE or FALSE?

47. A relay allows a low-voltage to control
a high-voltage circuit.

TRUE or FALSE?

48. A relay uses magnetism to open or
close a mechanical switch.

TRUE or FALSE?

49. Transformers allow circuits to be elec­trically isolated from each other.

TRUE or FALSE?

50. Snap Circuits® is fun.
TRUE or FALSE?

TESTYOURKNOWLEDGE

Answers are at www.snapcircuits.net/scstem1

.

-77-

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:45 PM Page 78

Other Snap Circuits

®

Products!

For a listing of local toy retailers who carry Snap Circuits®visit www.elenco.com or call us toll-free at 800-533-2441. For Snap Circuits

®

accessories, additional parts, and more information about your parts visit www.snapcircuits.net.

Snap Circuits

®

Model SC-300 with over 300 projects

iPod®shown
not included.

Snap Circuits®LIGHT

Model SCL-175

with over 175 projects

Snap Circuits®LIGHT contains over 55 parts
and over 175 projects to complete. Connect
your iPod®or any MP3 player and enjoy your
music as the lights change to the beat. The
strobe li ght with s pinning patterns will amaze
you with its visual effects. Features include: In­frared detector, color changing LED, glow-in­the-dark fan, fi ber opti c commun ication, and
color organ controlled by iP od

®

/MP3 player,

voice, and fingers.

Snap Circuits®Pro

Model SC-500 with over 500 projects

Snap Circuits®Extreme

Model SC-750 with over 750 projects

Contains over 60 parts

Contains over 75 parts

Contains over 80 parts

Snap Circuits®ARCADE

Model SCA-200

with over 200 projects includ-

ing 20+ games

Snap Circuits®ARCADE contains over 35 parts
along with over 200 projects including 20+ games
to complete. Create your own message to display
on the programmable word fan using the microcon­troller. Check out the cool dual LED display, change
it up with the bi-color LED, and get the party started
with the colorful disco ball! Clear and concise col­orful i llustrated man ual includes explanations for
different snap module s and concepts n eeded to
build ARCADE projects.

Snap Circuits®JR

Model SC-100 with over 100 projects

Contains over 30 parts

Model SC-SNAPINO

with over 20 projects

Snapino is an introduction to the open source Arduino Hardware­Software environment. Learn to code and utilize your Snap Circuits
modules at the same time!
A great general introduction to Coding and the Arduino platform
Arduino is a microcontroller used in robotics and other applications
Learn coding basics with
this kit and then further
expand into the Arduino
world using other Snap
Circuit kits!

Contains over

15 parts

Model SC-3DI

with over 150 projects

Taking Snap Circuits®to a whole new
dimension UP...OUT...and OVER!
Build over 150 projects
or combine with other
Snap Circuits

®

sets to
build even more unique
structures.

-78-

Contains over 60 parts

Snap Circuits 3D M.E.G. is a new kit
with fun and focus on “Magnetics”
“Electronics” “Gears”. Build over 160
projects with the over 60 included parts.
New parts include 3D Rotating Snaps,
2-sided base grid with thru-snaps, ro­tating mirror ball, gears, special
LEDs, melody IC, magnet
switch. New features in­clude Rotating LED
Lights, Fiber Optic Tree,
Rotating Mirror Ball, Ceiling
Fan and more.

Model SC-3MEG

with over 160 projects

Contains over 60 parts

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:46 PM Page 79

SC-STEM1 SELECT Block Layout

Important: If any parts are missing or damaged, DO NOT RETURN TO RETAILER.

Call toll-free [phone] or e-mail us at: [e-mail]. Customer Service ● 150 Carpenter Ave.
Wheeling, IL 60090 U.S.A.

Note: A complete parts list is on page 2 in this manual.

SC_STEM1_manual_PRINT.qxp_Layout 1 7/13/17 4:46 PM Page 80