Elenco Snaptricity reg User Manual

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Page 1

REV-A Revised 2011

Patent #‘s: 7,144,255, 7,273,377, & other patents pending

Page 2

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1. Most circuit problems are due to incorrect assembly, always double-check that y our circuit exactl y matches the drawing f or 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.

5. If the motor spins but does not balance the fan, chec k that there is a black plastic piece with three prongs on the motor shaft. In case it is damaged or lost, a spare is included with your kit. Pry the broken one off with a screwdriver and push the spare one on the shaft.

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

Basic T roubleshooting

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

Advanced Troubleshooting procedure on page 8 to determine which ones need replacing.

Batteries:

Basic T roubleshooting 1 Parts List 2 How to Use It 3 About Y our Snaptricity

Parts 4

DO’s and DON’Ts of Building Circuits 7

Advanced T roubleshooting 8 Project Listings 9 Projects 1 - 79 10 - 88 Other Snap Circuits

Projects 90

WARNING: SHOCK HAZARD - Never

connect your Snaptricity®set to the electrical outlets in your home in any wa y!

Table of Contents For the best learning experience, do the projects in order.

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.

W ARNING FOR ALL PARTS WITH A SYMBOL - Moving parts. Do not touch the

motor or fan during operation. Do not lean over the motor. Do not launch the fan at people, animals, or objects. Eye protection is recommended.

WARNING: CHOKING HAZARD - Small parts. Not

for children under 3 years.

Conforms

to ASTM

F963

• Use only 1.5V AA type, alkaline batteries (recommended, not included).

• Insert batteries with correct polarity.

•

Non-rechargeable batteries should not be recharged. Rechargeable batteries should only be charged under adult supervision, and should not be recharged while in the product.

• Do not mix alkaline, standard (carbon-zinc), or rechargeable (nickel-cadmium) batteries.

• Do not mix old and new batteries.

• Remove batteries when they are used up.

• Do not short circuit the battery terminals.

• Never throw batteries in a fire or attempt to open its outer casing.

• Batteries are harmful if swallowed, so keep away from small children.

WARNING:

This product contains a small magnet. Sw allowed magnets can stic k together across intestines causing serious infections and death. Seek immediate medical attention if magnet is swallow ed or inhaled.

Page 3

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

r 1

Base Grid (11.0” x 7.7”)

6SCBG

r 1

Motor 6SCM1

r 3

1-Snap Wire 6SC01

r 1

Fan Blade 6SCM1F

r 6

2-Snap Wire 6SC02

r 1

String 6SCM1S

r 3

3-Snap Wire 6SC03

r 1

Spare Motor Top 6SCM1T

r 1

4-Snap Wire 6SC04

r 1

Electromagnet 6SCM3

r 1

5-Snap Wire 6SC05

r 1

Iron Core Rod (46mm)

6SCM3C

r 1

6-Snap Wire 6SC06

r 1

Bag of Paper Clips 6SCM3P

r 1

Battery Holder -

uses

3 1.5V type AA (not included)

6SCB3

r 1

Thin Rod MWK01P5

r 1

Compass 6SCCOM

r 1

Grommet 662510

r 1

Copper Electrode 6SCEC

r 1

Meter 6SCM5

r 1

Zinc Electrode 6SCEZ

r 1

Magnet 6SCMAG

r 1

Iron Filings 6SCIF

r 1

Nut-snap 6SCNS

r 1

Jumper Wire (Black) 6SCJ1

r 1

Press Switch 6SCS2

r 1

Jumper Wire (Red) 6SCJ2

r 2

Slide Switch 6SCS5

r 3

Lamp 6SCL4

You may order additional / replacement parts at our

website: www.snapcircuits.net

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

Page 4

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How to Use It

Snaptricity®uses building blocks with snaps to build the different electrical and electronic circuits in the projects. Each block has a function: there are s witch bloc ks, lamp b loc ks, battery blocks, different length wire b locks , 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 bloc k which is green and has the marking on it. The par t symbols in this booklet may not exactly match the appear ance 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 diff erent layers.

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

kit).

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.

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.

3 4 5

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About Y our Snaptricity

Parts

(Part designs are subject to change without notice).

The base grid is a platform for

mounting parts and wires.

It functions like the

printed circuit

boards used in

most electronic

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

connect components.

They are used to

transport electricity and do not

affect 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 (like the projects using water).

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 electr

ical 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 wir

ing to complex radios.

The press switch (S2)

connects (pressed,

“ON”) or

disconnects (not

pressed, “OFF”)

the wires in a circuit. When ON it has no effect on circuit performance. It turns on electricity just like a faucet turns on water from a pipe.

The electrical symbol for a press switch is shown here.

The slide switch

(S5) connects

(ON) the center

snap to one of the

other two snaps.

When connected it has

no effect on circuit performance. It directs electricity just like a v alue controls water in a pipe.

The electrical symbol is shown here. It resembles the symbol for a door used in architect drawings for a house.

Engineers call this type of switch a SPDT (Single-Pole Double-Throw), representing how one point can be connected to either of two others.

SNAP WIRES & JUMPER WIRES

BATTERY HOLDER

PRESS SWITCH

Press Switch (S2)

SLIDE SWITCH

Slide Switch Symbol

Slide Switch (S5)

Battery Symbol

Battery Holder (B3)

Press Switch Symbol

Page 6

About Y our Snaptricity

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 , v ery 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.

-5-

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 mechanical 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)

Fan

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).

Page 7

About Y our Snaptricity

Parts

-6-

A light bulb, such as in the 4.5V lamps (L4), contains a special thin high-resistance wire. When a lot of electricity flows through, this wire

gets so hot it glows bright.

V oltages abov e 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

Lamp (L4)

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 increase magnetic media like floppy 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

Symbol 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 magnetism projects.

The copper and zinc electrodes are just metals that will be used for electrochemical projects.

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

Symbol without Rod

Page 8

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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

w-resistance 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 components 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 circuits you create. If they are unique, we will post them with your name and state on our website at www.snapcircuits.net/kidkreations.htm. Send your suggestions to ELENCO

: elenco@elenco.com.

ELENCO

provides a circuit designer so that you can make y our o wn

Snap Circuits

drawings. This Microsoft®Word document can be downloaded from www.snapcircuits.net/SnapDesigner.doc or through the www.snapcircuits.net web site.

WARNING: SHOCK HAZARD - Never connect your

Snaptricity®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 (S5) 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!

Page 9

-8-

Advanced Troubleshooting

(Adult supervision recommended)

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

If you suspect you have damaged parts, y

ou can follow this procedure to systematically determine which ones need replacing:

1. 4.5V lamps (L4), motor (M1), and battery

holder (B3): Place batteries in holder.

Place the 4.5V lamp directly across the batter

y holder, it should light. Do the same with the motor (motor + to battery +), it should spin to the right at high speed (use two 1-snap wires as spacers). If none w ork then replace your batteries and repeat, if still bad then the battery holder is damaged.

2. Set the motor (M1) by itself and place the fan on it. If the Motor (M1) does not

balance the fan e

venly: 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 this mini-circuit to test each of the snap wires

, one at a time. The

lamp should light.

5. Slide switch (S5): Build project 10. With the s

witch in the left position (C), the left lamp should be on. With the switch in the right position (B), the right lamp should be on.

6. Press switch (S2): Build project 75. When y

ou press the switch, the lamp should light.

7. Meter (M5): Build project 75, 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 46 and place the iron core rod in the electromagnet. When y

ou press the switch (S2), the rod in

the electromagnet should act like a magnet.

9. Iron filings: Sometimes the filings may stic

k 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. Compass and magnet: The red compass needle should point nor

th, unless it is near a magnet or large iron object. The red compass needle will point toward the black (S) side of the magnet.

ELENCO

150 Carpenter Avenue

Wheeling, IL 60090 U.S.A.

Phone: (847) 541-3800

Fax: (847) 520-0085

e-mail: help@elenco.com

Website: www.elenco.com

You may order additional /

replacement par

ts at:

www.snapcircuits.net

Page 10

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

Project Listings

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Welcome to Electronics

1 Electronic Playground 10 2 Parallel Play 11 3 Wicked Switches 12 4 Spinning Cylinder Suspender 13

Static Electricity

5 Electricity Y ou Can Wear 14 6 Electricity In Your Hair 15 7 Bending Water 16 8 More Static Tricks 17

Electrical Materials

9 Light the Way (Lamp circuit) 18 10 Flip It (2-position switch) 19 11 Pushing Electricity 20

(Voltage across lamp)

12 Pushing a Lot of Electricity 21

(Voltage across motor)

13 What’s An Ohm? 22

(Find lamp resistance)

14 Be a Scientist 23

(Conductors and insulators)

15 Make Your Own Parts 24

(Resistance of graphite in pencils)

16 Hydro-Resistors 25

(Resistance of water)

Basic Electrical Circuits

17 One Way Around 26

(Lamps in series)

18 Many Paths 27

(Lamps in parallel)

19 Parallel Swapping 28 20

Series Swapping 29

21 Light Bulb 30

(Incandescent light bulbs)

22 Batteries in Series 31 23

Batteries in Parallel 32

24 Voltage Divider 33

(Voltages in a series circuit)

25 Voltage Shifter 34

(Currents in a series circuit)

26 T riple Voltage Divider 35

(Voltages in a series circuit)

27 Triple Switching Voltmeter 36

(Voltages in a series circuit)

28 Triple Switching Ammeter 37

(Currents in a series circuit)

29 Current Divider 38

(Currents in parallel circuits)

30 Ohm’s Law 39

(Measuring resistance of parts)

31 Ohm’s Law - Cold Lamp 40

Putting Electricity to Use

32 2-Way Switch 41

(Switching for lights in home)

33 Another 2-Way Switch 42 34

3-Speed Motor 43

(Regulating motor speed with lamps)

35 3-Speed Motor (II) 44 36

3-Speed Motor (III) 45

37 3-Position Switch 46

(Simulate more complex switch)

38 3-Position Switch (II) 47 39

4-Position Switch 48

40 AND 49

(Simulate an AND gate with switches)

41 AND NOT 50

(Simulate a NAND gate with switches)

42 OR 51

(Simulate an OR gate with switches)

Magnetism

43 Compass 52 44 Magnetic Fields 53 45 Iron Extension 54

(Extending a magnet with an iron bar)

46 Electronic Magnet 55 47

Electromagnet Magnetic Field 56

48 Electromagnet T o wer 57

(Suspending iron rod in air)

49 Electromagnetic Suspender 58 50

Electromagnet Direction 59

(Reversing current)

51 Wire Magnet 60

(Magnetic field from wire)

52 Magnetic Induction 61

(Induce a current in a coil)

Motor Circuits

53 Motor 62 54 Propeller and Fan 63 55 Back EMF (Motor characteristics) 64 56 Generator 65

(Make a current with the motor)

57 Make Your Own Generator 66

(Make current with the motor)

58 String Generator 67

(Use string to spin the motor faster)

59 Motion Enhancer 68 60

Holding Down 69

(Overloading batteries)

Advanced Magnetic Circuits

61 Make Your Own Electromagnet 70 62 Relay (Build a relay) 71 63

Relay (II) 72 64 Relay (III) 73 65 Buzzer 74

(Build a buzzer with the electromagnet)

66 Buzzer (II) 75 67 Reed Switch 76

(Magnetically controlled switch)

68 Reed Switch (II) 77

Electrochemistry

69 Cola Power 78

(Use soda as a battery)

70 Fruit Power 79

(Use fruit as a battery)

71 Water Impurity Detector 80

(Current from water)

Fun with Electricity and Magnetism

72 Indian Rope Trick 81

(Suspend objects in air)

73 Hypnotic Discs 82

(Spinning patterns)

74 Spin Draw 83 75

Morse Code 84 76 Flying Saucer (Launch the fan) 85 77

Power Light Regulator 86

(Regulate lamp brightness)

78 Raising the Bar 87 79

Electromagnetic Playground 88

Page 11

Project #1

Electronic Playground

WARNING: Moving parts.

Do not touch the fan or motor during operation.

WARNING:

Do not lean over the motor .

Build the circuit shown by placing all the parts with a black 1 next to them on the clear plastic base grid first. Then, assemble parts marked with a 2, and finally the parts marked with a 3. Be sure to place the motor (M1) with the (+) side oriented as shown. Place the iron core rod into the electromagnet (M3) as shown, set the meter (M5) to the 1A scale, place the fan on the motor, and install three (3) “AA” alkaline batteries (not included) into the battery holder (B3).

Assembly

Depending on the position of the slide switches (S5), the fan will spin, and in rare cases, fly into the air. Do not lean over the fan when it is spinning. Pushing the press switch (S2) will attract the compass to the electromagnet (M3).

You may need to giv e the f an a push with y our finger to get it started.

Operation

Educational Corner:

-10-

This diagram is a simplified drawing of the circuit, with the components represented by symbols (the symbols are explained on pages 4-6). Engineers use these diagrams, called schematics, because dr

awing pictures of their circuits takes too much time and the connections are often unclear.

Electric Paths

Placement Level

Numbers

Placement

Level

Numbers

Snappy says:

electronics can

be lots of fun!

Page 12

Project #2

parallel play

Educational Corner:

-11-

Electric Paths

Electronics is the science of working with and controlling

electricity.

Build the circuit as shown. Set the meter (M5) to the 5V scale.

Assembly

Set the right slide switch (S5) to “C” to tur n on the circuit. The meter (M5) measures the voltage. The compass is attracted to the electromagnet (M3). The left slide switch (S5) can bypass the bottom lamp. Pushing the press switch (S2) will spin the fan.

Operation

This circuit spreads the electricity from the batteries into four parallel sub-circuits to do different things. Connecting electrical components in parallel means they are between the same points in a circuit. You will learn about parallel circuits later.

Description

WARNING: Moving parts.

Do not touch the fan or motor during operation.

WARNING:

Do not lean over the motor .

Snappy says: electricity can be used to do lots of different tasks at once.

Page 13

Snappy says:

switches are used all

over electronics - try

to count how many

are in your home!

Project #3

wicked switches

Educational Corner:

Electric Paths

Switches are used to turn electrical appliances on or off, or to change electrical connections.

The light in your refrigerator is activated by a switch. Each of the buttons on your computer keyboard controls a switch, and there are several switches in the computer’s mouse.

Build the circuit as shown. Set the meter (M5) to the 1A scale.

Assembly

Push the press switch (S2) to turn on the circuit. Flip the slide switches (S5) and see what happens. You may need to give the fan a push with your finger to get it started.

Operation

The slide switches direct the electricity between the different circuit paths (each has a lamp). You will learn more about switches later.

Description

WARNING: Moving parts.

Do not touch the fan or motor during operation.

WARNING:

Do not lean over the motor .

-12-

Page 14

Project #4

-13-

Electric Paths

Educational Corner:

Spinning Cylinder

Suspender

Build the circuit as shown. Set the meter (M5) to the 1A scale. Drop the thin rod into the electromagnet.

Assembly

Set the right slide switch (S5) to “C” to tur n on the circuit. The thin rod gets suspended in mid-air by the electromagnet. The left slide switch (S5) selects whether the lamps or motor are on.

Operation

The thin rod is held in the air by electromagnetism, which you will learn more about later.

Description

WARNING: Moving parts.

Do not touch the fan or motor during operation.

WARNING:

Do not lean over the motor .

Snappy says: it seems like magic, but it’s electromagnetism!

Page 15

Project #5

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

Educational Corner:

Did you ever wonder why clothes cling together when they come out of the dryer? Did you ever hear a crackling sound when you take off a sweater? (If the room is dark you might even see sparks.) Did y ou e v er feel a “zap” when you touch someone wearing a sweater on a dry day? These effects are caused by electricity. We call this static electricity because the electr

ical 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 mater

ial. All materials are made up of atoms, which

are really

, really tiny. Atoms hav e a nucleus (which has

positive electrical charges), which is surrounded by tiny

electrons (negative electrical charges). When y ou rub

a mater

ial, 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

travels faster than

sound.

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.

-14-

Electrons

–

Nucleus

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

The crackling noise you hear when taking off a sweater is static electricity. You may see sparks when taking one off in a dark room.

Electricity You Can Wear

Snappy says: clothes

can cling together

because electricity is

all around us.

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

Page 16

Snappy says: notice how your hair can “stand up” or be attracted to the comb when the air is dry . W etting your hair dissipates the static charge.

-15-

Project #6

Educational Corner:

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 ma y be a weak attr action). Now hold the magnet near the iron filings; they jump to it easily.

What’s happening? 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.

Do you want to learn more?

Iron filings are

weakly attracted

to the comb.

Iron filings are

strongly attracted

to the magnet.

Electricity in Your Hair

You need a comb (or a plastic ruler) and some paper for this project. Rip up the paper into small pieces.

Assembly

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).

Operation

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

Description

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.

Page 17

Project #7

Educational Corner:

Static electricity was discovered more than 2,500 years ago when the Greek philosopher Thales noticed that when amber (a hard, clear, y ellow-tinted material) is rubbed, light materials like feathers stick to it. Electricity is named after the Greek word for amber, which is electron.

Other facts about Static Electricity:

1. Static electricity in the atmosphere causes the “static” (erratic noises) you hear on your AM radio when reception is poor.

2. Static Electricity can damage some types of sensitive electronic components. Electronics manufacturers protect against this using static-dissipating wrist straps, floor mats, and humidity control. Your Snaptricity

parts will not be

damaged by static.

3. Some homes have “lightning rods”, which are metal bars from the roof to the ground. These help protect the home by encouraging lightning to go through the the rods instead of the house.

Anti-Static Wrist Strap

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.

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Lightning Rod

Bending Water

You need a comb (or plastic ruler) and a water faucet for this project.

Assembly

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

Operation

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

Description

Snappy says: big planes can build up a large static charge in flight. They are usually connected to something like a lightning rod as soon as they land.

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Project #8

More Static Tricks

Educational Corner:

Electricity vs. Gravity:

Electricity is immensely more powerful than gravity (gra vity is what causes things to fall to the ground when you drop them). Howe v er 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.

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

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

1. Corona wire charges drum with static electricity

2. Light from white areas of document being copied destroys the charge.

3. Toner from roller is attracted to the charged areas.

4. Toner image transfers to charged paper.

5. Heated rollers bond toner image to paper.

In many photocopiers, a drum is charged with static electricity. Light from the white areas of the document being copied destroys the charge, but dark areas of the document leave a pattern of charge on the drum. Toner (a powder) is attracted to the charged areas, creating an image. The toner is then transferred to paper and melted on.

Electricity Gravity

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.

Snappy says: how well a material can hold an electric or magnetic charge depends on the characteristics of the material.

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Project #9

Light the Way

Educational Corner:

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 slide switch (S5) controls the electricity by turning it on or off, just like a light switch on the wall of your home. A switch controls electricity like a faucet controls water.

4. The lamp (L4) converts electrical energy into light, it is the same as a lamp in your home except smaller. In a light bulb, electricity heats up a high-resistance wire until it glows. A light bulb shows how much electricity is flowing in a circuit like a water meter shows how fast water flows in a pipe.

5. 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:

Electric Paths

-18-

Build the circuit shown by placing all the parts with a black 1 next to them on the clear plastic base grid first. Then, assemble parts marked with a 2. Scre w a bulb into the lamp socket (L4) and install three (3) “AA” batteries (not included) into the battery holder (B3).

Assembly

This circuit is just like a lamp in your home, when you flip the switch (S5) to on (position B), the lamp (L4) will be on.

Operation

Snappy says: touch the light and feel how warm it is. Only about 5% of the electricity is converted into light, the rest becomes heat. Don’t touch light bulbs in your home because they can be very hot.

Page 20

Educational Corner:

Flip It

Project #10

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The slide and press switches included in Snaptricity®are simple switches, more complex types are also available. Switches come in almost every shape and size imaginable. There are membrane, rocker, rotary, DIP, push button, and momentary types just to name a few.

Very often, a single switch is used to make many different connections. The combinations of connections for a switch are indicated in the symbol for it. Here are some examples:

The “on” position of a s witch 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 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

Rotary Switch

Schematic

Slide Switch

Schematic

Walls

Door

Left switch position

closed

(turned on)

Right switch position

open

(turned off)

Left switch position

open

(turned off)

Right switch position

closed

(turned on)

Open Switch (turned off)

Electric Paths

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

Closed Switch (turned on)

Your S5 switch has 2 positions, so it has a different symbol:

Build the circuit shown.

Assembly

The slide switch (S5) directs the electricity to either of two paths (both lamps here). It is like many switches in your home, controlling different lights in the same area.

Operation

Replace the 3-snap wire with the press switch (S2). Now either lamp (L4) is only on when S2 is pressed.

Variant

Page 21

Pushing Electricity

Project #11

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Educational Corner:

Build the circuit and connect the red jumper wire as shown. Set the meter (M5) to the 5V setting and the slide switch (S5) to position C at first.

Assembly

Read the battery voltage on the meter (the top scale), it should be about 4.5V. The lamp will be off.

Flip the switch to position B; the lamp lights and the v oltage drops a little. (To learn why the voltage drops now, ask Snappy.)

Move the red jumper wire from position A on the switch to position B. The battery voltage is the same here because none is lost across the switch.

Now flip the switch to position C (OFF); the voltage at the lamp drops to zero and it shuts off.

Operation

Electricity is the movement of sub-atomic charged particles (electrons) through a material due to electrical pressure across the material, such as from a battery.

The electrical pressure exerted by a battery or other power source is called voltage and is measured in volts (V, and named after Alessandro Volta who invented the battery in 1800). Notice the

“+” and “–” signs on the battery. These indicate which direction the battery will “pump”

the electricity. Circuits need the right voltage to work properly . F or e xample, if the electrical pressure to a lamp

is too low, then the bulb won’t turn on; and if too high, then the bulb will overheat and burn out. 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, named after Andre Ampere who studied the relationship between electricity and magnetism) or

milliamps (mA, 1/1000 of an ampere).

Record the voltage you measured here, it will be used in project 13:

Snappy says: the batter y voltage drops when the lamp is connected because the batteries have trouble supplying as much electricity as the lamp would lik e. Remember that a battery produces electricity from a chemical reaction. Not only is there a limited amount of the chemicals in a small battery (batteries slowly get weaker as you use them), but also not all of the material can react together at the same time.

Page 22

Educational Corner:

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Pushing a Lot of Electricity

Project #12

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.

Batteries are made from materials like zinc and magnesium dioxide, electricity flows as these react with each other. As more material is used up by the reaction, the battery voltage is slowly reduced until eventually the circuit no longer functions and you have to replace the batteries. Some batteries, called rechargeable batteries (such as the batteries in your cell phone), allow you to reverse the chemical reaction using another electric source.

Snappy says voltage is sometimes called electromotive-force (EMF) because it pushes the electrons through the circuit.

Build the circuit as shown; it is the same as the preceding one except the lamp (L4) was replaced by the motor (M1). Set the meter (M5) to the 5V setting and the slide switch (S5) to position C at first.

Assembly

Read the battery voltage on the meter (the top scale), it should be about 4.5V. Flip the switch to position B; the fan spins and the voltage drops - more than it did with the lamp.

Turn off the circuit and remove the fan. T urn the switch bac k on and read the voltage; it doesn’t drop as much without the fan.

Operation

It takes a lot of current to spin the fan as f ast as it would lik e to go, and the batteries can’t produce enough. As a result, the voltage (electrical pressure) from the batteries drops.

It’s a lot easier to spin the motor shaft without the fan on it, so the voltage doesn’t drop much without the fan.

Description

WARNING: Moving

parts. Do not touch the fan or motor during operation.

WARNING: Do not

lean over the motor.

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What’s An Ohm?

Project #13

Snappy says: the Ω

symbol is the last letter in

the Greek alphabet and

is pronounced Omega.

Educational Corner:

The resistance of a circuit represents how much it resists the electrical pressure (voltage) and limits the flow of electric current. The relationship between voltage, current, and resistance is the most important one in electronics. It is known as Ohm’s Law (after George Ohm who disco

vered it in 1828):

When there is more resistance, less current will flow unless you increase the voltage. Resistance is measured in ohms. The symbol used for an ohm is Ω.

Using the voltage measurement you made in project 11 and the current measurement you made here, you can calculate the resistance of the lamp. It is usually 15-20 ohms.

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.

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 electr

ical 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.

Voltage

Resistance

Current =

The “power” of electricity is a measure of how fast energy is moving through a wire. It is expressed in Watts(W, after James W

att for his work with engines). It is a combination of the electrical voltage (pressure) and current:

Power = Voltage x Current

Using the voltage and current measurements you made, you can calculate the power of the lamp. It should be about 1 watt. Compare this to the light bulbs in your home, which are usually about 40-100 watts.

Voltage x Voltage

Resistance

Power =

Electric

Paths

= Current x Current x Resistance

Build the circuit shown. Set the meter (M5) to the 1A setting.

Assembly

Set the slide switch (S5) to position B to measure the current through the lamp (L4).

Operation

Page 24

Snappy says: 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.

-23-

Be A Scientist

Project #14

Educational Corner:

Some materials, such as metals, have v ery 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 n

ucleus 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 ha

ve their electrons locked in tight

and have no room for more. Did you ev er hear the term “blown fuse”?

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

Fuses are designed to shut do

wn a circuit when 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. Small battery-powered products usually do not have them because the batteries are not powerful enough to cause harm.

Some fuses need to be replaced after they “blow”, but others can be reset by flipping a switch. Every home has an electrical box of resetable fuses, it may look like this:

This wire melts to break the circuit.

Build the circuit shown, the can be anything you want. Set the meter (M5) to the 1A setting.

Assembly

Turn on the slide switch (S5, position B) and touch various materials between the snaps on the switch and meter. 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, s witch it to the 1mA setting to see if there is just a very small current. To help protect the meter, alw a ys switch bac k to the 1A scale before testing a new circuit.

Operation

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Educational Corner:

Make Your Own Parts

Project #15

Build the circuit shown, set the meter (M5) to the 1mA setting.

Assembly

Make your parts using either the water puddles method (A), the drawn parts method (B), or the pencil parts method (C). Set the slide switch (S5) to position B to turn on the circuit. T ouch the metal in the jumper wires to your parts and read the current in milliamps.

Operation

1mA

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.

Voltage Current

Resistance =

Snappy says: long narrow shapes have more resistance than short wide ones.

1mA

Method A (easy): Spread some water on the table into

puddles of different shapes, perhaps like the ones sho wn 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.

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

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.

Page 26

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Educational Corner:

Hydro-Resistors

Project #16

Build the circuit shown. Set the meter (M5) to the 1mA setting. Add about 1/4 inch of water to a cup or bowl. Connect the jumper wires and place them in the water, make sure the metal parts aren’t touching each other. Set the slide switch (S5) to position B to turn the circuit on.

Assembly

Measure the current through the water. 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. Nor mal 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.

Operation

1mA

Depending on your local water supply, your current measurement may exceed the 1mA scale. You can s witch 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. A high reading of 4V or more means the water has relatively low resistance.

1mA

Snappy says: 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.

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Educational Corner:

One Way Around

Project #17

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.

Snappy says: the 0V or “–” side of the battery is often referred to as “ground”, since in house or building wiring it is connected to a rod in the ground as protection against lightning.

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:

series = R1 + R2 + R3 + . . .

The current is the same through all the resistances in a ser

ies 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)

Electric Paths

Strings of Christmas lights are little low-voltage lamps connected in series to the house power (120V). They are inexpensive, but if one bulb falls out, then the entire string will be off.

Most strings will still work if one bulb burns out because a special heat-activated bypass wire is built into each bulb. When the bulb burns out, the full house voltage is across the bypass wire, which heats it until it turns on. Sometimes only half the bulbs in a string are lit. This is because some long strings are actually two (or more) shorter strings connected in parallel.

Build the circuit and push the press switch (S2). The lamps (L4) are all on, but are dim.

Assembly

The three lamps are connected in a series. They are dim because the voltage from the batteries (B3) is divided between them.

Description

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Educational Corner:

Many Paths

Project #18

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 (unscrew one of the bulbs 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.

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

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)

Electric Paths

Build the circuit and push the press switch (S2). The lamps (L4) are all bright.

Assembly

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.

Description

1111

= + + + . . . .

parallel R1 R2 R3

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Educational Corner:

Parallel Swapping

Project #19

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.

B C

Part B Part C

Electric Paths

Snappy says: the order of parts connected in series or in parallel does not matter - what matters is how combinations of these subcircuits are arranged together.

Push the press switch (S2); the lamp lights (L4) 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 v oltage at each location, it should be the same.

Part C: s wap the locations of the meter and lamp . The meter should still measure the same voltage.

Operation

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.

Description

Build the main circuit and set the meter (M5) on the 5V setting.

Assembly

Page 30

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Educational Corner:

Series Swapping

Project #20

Which way does electricity really flow? In the Electric Paths

drawings (schematics), 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.

Electric Paths

Push the press switch (S2); the lamps (L4) light and the meter (M5) measures the current through the circuit.

Now swap the positions of any of the lamps, 3-snap wires, the press switch and the meter (the meter should alwa ys be placed so it hangs out of the circuit). Read the current on the meter, it should be the same ho we ver the parts are arranged.

Note: Y our M5 meter is a simple meter. It ma y read zero on this scale even though a small current is flowing.

Operation

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

Description

Build the main circuit and set the meter (M5) on the 1A setting.

Assembly

Examples

Snappy says: 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.

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Educational Corner:

Light Bulb

Project #21

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 tak e a fe w seconds before they make any light?

Incandescent bulbs like these make light by passing a big electric current through a special high-resistance wire, 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.

Electric Paths

Do you want to learn more?

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.

The fluorescent light bulbs that come in white 4 ft. tubes are the standard room lights f

or offices and schools. They pass electric current through a gas, usually argon. This gas emits light as the electricity passes through it, similar to how a tungsten wire does. Although larger and more expensive than ordinary incandescent lamps, they are typically five times more efficient at converting electricity into light.

The difference in heat produced between incandescent and fluorescent light bulbs might surprise you. Find a fluorescent 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. Only about 5% of the electricity used by incandescent bulbs is converted into light. Without the more efficient fluorescent bulbs, our society of office buildings might have been much different.

Build the circuit and hold down the button on the press switch (S2). Two lamps (L4) are very dim while one is bright.

Operation

All the electric current flows through the top lamp, then divides between the two lamps on the left. The top lamp is much brighter than the others because it has twice as much electricity flowing through it.

Description

Snappy says: most of the electrical energy used by these bulbs becomes heat, not light.

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Educational Corner:

Batteries in Series

Project #22

Part A: Since the battery holder (B3) has three 1.5V type AA batteries in series, you should measure about 4.5V (1.5V + 1.5V + 1.5V = 4.5V).

Part B: Since you are measuring two 1.5V type AA batteries in series, you should measure about 3V (1.5V + 1.5V = 3V).

Par t C : Since you are measuring one 1.5V type AA battery, you should measure about 1.5V.

Part C

Part B

Part A

A. Read the voltage on the meter. If your batteries are new

then it should be about 4.5V.

B. Remov e 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.

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.

Operation

When batteries are connected in series, they add together, making the total voltage higher.

Description

Build the circuit as shown and set the meter (M5) to the 5V setting.

Assembly

Snappy says: you can also connect the black jumper wire to the 3-snap wire, then touch the red and black jumper wires across the terminals of any low voltage battery to measure it, or just use the meter with the jumper wires connected to it.

Page 33

Description

Operation

Batteries in Parallel

Project #23

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FOR ADVANCED USERS - ADULT

SUPERVISION RECOMMENDED

Remove parts from the circuit until it looks like the Part B drawing.

Assembly

Touch the red or black jumper wires to the metal contacts for the center battery as shown. The single bulb (L4) will glow brighter than in the original circuit when only one battery is connected. Note: Y our M5 meter is a simple meter. It ma y read z ero on this scale even though a small current is flowing.

Now connecting both batteries at once doesn’t change the brightness or increase the current measured, because a single battery can supply as much current as this simple circuit needs.

Part B

Touch the red or black jumper wires to the metal contacts for the center battery as shown. The bulbs (L4) will barely glow and the motor (M1) will probably need a push to get it started. The meter measures the current.

Touching both on at the same time connects both batteries in parallel. This makes the b ulbs glow a little more, mak es the motor spin faster, and increases the current on the meter.

Operation

When batteries are connected in parallel they can supply more current to a circuit. This means more power.

Description

Remove the center battery from the battery holder (B3). Build the circuit as shown. Set the meter (M5) to the 1A setting.

Assembly

Educational Corner:

Electric Paths

Snappy says:

batteries are

pushy little guys.

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Voltage Divider

Project #24

Educational Corner:

One of the most basic rules for analyzing circuits is

Kirchhoff’s V oltage Law (named after Gustav Kirchhoff , who

stated it in 1847):

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: (V

batteries = Vlamp1 + Vlamp2)

Electric

Paths

Wow! It really

does all add up.

A. Set both slide switches (S5) to position B and push the

press switch (S2). Both lamps (L4) light and the meter measures the voltage across the top one.

B. Set both slide switches to position C and push the press

switch. Now the meter measures the voltage across the bottom lamp (it should be the same as for the top one).

C.Set the top slide switch to position B and the bottom

switch to position C, then push the press s witch. Now the meter measures the voltage across both lamps (it should be the individual lamp voltages added together).

Operation

When equal components are placed in series, each having the same resistance to the flow of electricity, the total voltage will divide equally between them.

Description

Build the circuit shown. Place the meter (M5) on the 5V setting.

Assembly

Page 35

Sometimes switches are pretty swift, they can sneak current around a lamp and make voltage shift.

Voltage Shifter

Project #25

-34-

Educational Corner:

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.

Electric Paths

Both lamps (L4) are on and the meter shows the voltage across the top lamp, which is half the battery holder (B3) voltage.

Push the press switch (S2) to bypass the bottom lamp and remove it from the circuit. Now the top lamp is much brighter and the meter shows that the full battery voltage is across it.

Operation

Modify the preceding circuit into this one. Keep the meter (M5) on the 5V setting.

Assembly

Page 36

Educational Corner:

-35-

Project #26

Electric

Paths

If a circuit is given too much voltage then its components will be damaged. It is like having the water in your f aucet 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.

Batteries can be selected to give a circuit just the voltage it needs. The electricity produced by your electric company comes at a higher voltage, which must be converted down for many circuits.

Snap the loose end of the red jumper wire to points A, B, C, or D . Push the press switch (S2) 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.

Operation

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.

Description

Build the circuit and set the meter (M5) on the 5V setting.

Assembly

Triple Voltage Divider

B C

Try to count how many batteries are in your home. Your count will probably be low. Many products that use your house power also have batteries to retain clock or programmed information during brief power outages (such as computers).

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Educational Corner:

Triple Switching Voltmeter

Project #27

Electric Paths

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.

Set the slide switches (S5) to position C. Push the press switch (S2); the meter measures the voltage across the right lamp.

The slide switches control the left two lamps (L4), individually. If the lamps are on (switch position B), the battery voltage is split among them and less voltage will be measured across the right lamp.

Operation

This is another example of how v oltage divides as parts are added in series.

Description

Build the circuit and set the meter (M5) on the 5V setting.

Assembly

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Educational Corner:

Triple Switching Ammeter

Project #28

Electric Paths

Most electronic products have almost all of their components and wires mounted on special boards. In these boards, the “wires” connecting

parts are literally “printed” on the surface of the board; hence the boards all are called “printed circuit boards” or PCBs.

Operation

This is an example of how current decreases as parts are added in series. When the slide switches are in position C, no current flows

through the bypassed lamp because the switch has very low resistance.

Description

Build the circuit and set the meter (M5) on the 1A setting.

Assembly

Set the slide switches (S5) to position C.

Push the press switch

(S2); the meter measures the current through the right lamp. The slide switches control the left two lamps (L4), individually. If the

lamps are on (switch position B), the battery voltage is split among them and less current will be measured through the lamps.

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

Snappy says: switches come in many diverse forms. Try to count how many are in your home or car; you will be amazed. There are slide, press, membrane, rotary, push-button, and other switches controlling nearly everything.

Page 39

Snappy says: connecting parts in parallel allows more current to flow, so it decreases the overall circuit resistance.

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Educational Corner:

Project #29

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 low accuracy.)

Kirchhoff’s Current Law, an

impor

tant 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

)

The total battery current here is much higher than in project 13, because this circuit has several lamps in parallel. The lamps are acting as resistors, limiting the flow of electricity in the circuit. As resistances are added in parallel, they increase the total current.

Part B

Current Divider

Part C Part D

Electric Paths

B C

Par t A: Push the press switch (S2); the meter measures the

current from the batteries (B3). Par t B: Swap the location of the meter with the 3-snap wire

marked “B” (“+” side towards the lamp). Push the switch to measure the current through circuit branch “B”.

Par t C : Swap the “B” location of the meter with the “C” 3-snap. Push the switch to measure the current through the “C” branch.

Part D: Swap the “C” location of the meter with the “D” 3-snap. Push the switch to measure the current through the “D” branch.

Operation

The current from the batteries splits up between the three lamps, because they are connected in parallel.

Description

Build the main circuit and set the meter (M5) on the 1A setting.

Assembly

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Project #30

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Educational Corner:

Ohm’s Law

Build the circuit as shown (leave the f an off the motor (M1). Set the meter (M5) on the 1A setting, place the iron core rod into the electromagnet (M3), and both slide switches (S5) to the B position (off).

Assembly

Since the battery voltage is 4.5V , y ou can use Ohm’ s Law to calculate the resistance of each part:

Notes: Your actual results may vary. Unless your batteries are new, the v oltage may be less than 4.5V. Also, your M5 meter is a simple meter . Don’t expect it to be as accurate as normal electronic test instruments. In some cases, the meter may show zero current for the electromagnet; switch the meter to the 1mA scale to prove a current is flowing.

Another problem is that the battery voltage drops a little if the current is high. This drop ma y be 1-2 v olts for the motor with fan. For some motors, typical resistance may be 3 ohms with fan and 20 ohms without fan.

Optional: For a more accurate resistance measurement, you can measure the actual voltage. Place the meter across the battery holder, set it to the 5V scale, and place a 3-snap wire where the meter used to be. Use the switches to measure the voltage for each part individually, as you did for the current.

By comparing the currents you measured, you can see which part has the most resistance to the flow of electricity.

Description

Voltage Current

Resistance =

WARNING: Moving par ts. Do not touch

the fan or motor during operation.

WARNING: Do not

lean over the motor.

Operation

Set the left slide switch to position C to turn on the lamp (L4). The meter measures the electric current through the lamp.

Set the left switch back to B and set the right slide switch to position C. Now the meter measures the current through the electromagnet. The electromagnet will attract the compass needle.

Set the right slide switch back to B and push the press switch (S2). Now the meter measures the current through the motor.

Last, place the fan on the motor and measure its current with the fan on.

Electric Paths

Voltage

Measured

Current

Measured

Resistance

Calculated

Typical

Resistance

Lamp 4.5 volts 15 ohms

Electromagnet

4.5 volts 30 ohms

Motor (with fan)

4.5 volts 10 ohms

Motor (without fan)

4.5 volts 40 ohms

FOR ADVANCED USERS - ADULT

SUPERVISION RECOMMENDED

4.5V

Current

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Ohm’s Law - Cold Lamp

Project #31

Part A: Build the circuit at left and set the meter (M5) on the 5V

setting. Push the press s witch (S2) to measure the v oltage across the top lamp, which is bright.

Part B: Move the meter so it is across base grid locations C2-E2. Push the press switch to measure the voltage across the lower lamps, which are very dim. Watch the lower lamps closely as you press the switch. Initially the y 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.

Operation

The top lamp turns on faster and brighter because it has a higher current through it, which heats up the filament quickly. The other lamps turn on slowly and dimly because they have half the current, which is barely enough to heat up their filaments.

Description

The preceding circuit allowed you to calculate the resistance of the lamp (L4) by measuring the voltage and current. You did this while the lamp was bright, but the lamp has much lower resistance when it is dim.

Assembly

Educational Corner:

The current through the top lamp is split between the two lower lamps, so you would probably expect the lower lamps to be half as bright and to have half as much voltage across them. Instead, they are much dimmer and have a lot less voltage.

This happens because a dim light bulb has less resistance than a bright one! Your L4 light bulbs have resistance of less than 5 ohms when dim, and about 15 ohms when bright.

Voltage Current

Resistance =

Electric Paths

Snappy says: when a large current flows through the lamp, the filament (a special high-resistance wire) heats up and glows. All wires have higher resistance when they are very hot.

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Educational Corner:

2-Way Switch

Project #32

Electric

Paths

Example:

The lamp could be an overhead light in a hallwa y, and one slide switch would be at each end of the hallway. Whene ver y ou walk into the hallw ay y ou flip the switch to turn on the light, and flip the other switch to turn off the light when you leave the hallway on the other side.

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Snappy says: batteries are widely used because they are easy-to-use, safe, and portable.

Whenever you flip either switch (S5), the lamp (L4) will change (turning on or off).

Operation

This switch arrangement is used to control room lights in almost every home.

Description

Build the circuit as shown.

Assembly

Light Switch

(on)

Light Switch

(off)

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Another 2-Way Switch

Project #33

Educational Corner:

Only a tiny portion of the electricity used in our world comes from batteries. The rest is produced at enormous electric power plants, operated by your local electric company. The electricity from these power plants is available at each of the electrical outlets in the walls of your home. The voltage of this electricity is 120V, much higher than the voltage of the batteries in Snaptricity

. The current available is very large, since it must power products like dishwashers and TVs.

Our lives are much easier and more fun by having such power available by simply plugging into an electrical outlet. This amount of electr icity is also very dangerous, and it will kill anyone who abuses it. While accidents involving electricity are rare, they kill people ever y year.

Never put anything into an electrical outlet except an electrical plug. Battery-powered products are safe,

since small batter

ies are too weak to hurt people.

The protective plastic around the wires of a lamp plug are all that protects you from the full power of electricity. Damaged electrical cords should always be unplugged and repaired. Remember that electricity travels through water, so don’t use electric products while taking a bath (battery-powered products are fine).

Your home has fuses that automatically turn off the electricity in your home if there is an electrical problem, such as a short circuit. These fuses prevent electrical problems in your home from affecting y our neighbors, but they do not protect you.

Electric Paths

Whenever y ou flip either s witch (S5), the lamp (L4) will change (turning on or off).

Operation

This is another common switch arrangement used to control room lights in homes. It can be used to control many lights at the same time.

Description

Build the circuit as shown.

Assembly

The cost of electricity from the electric company is much less than the cost of electricity from batteries.

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3-Speed Motor

Project #34

Snappy says: This is one way to control the speed of a motor.

Educational Corner:

Place the fan on the motor. Set both slide switches to position B and push the press switch. The motor will not spin.

Now set the slide switches to position C, push S2 to get the motor spinning, then set the slide switches back to B. 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.

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

Electric Paths

Do you want to learn more?

Friction

Push the press switch (S2) to turn on the motor and use the slide switches (S5) to control its speed. The meter (M5) measures the current. You may need to give the motor a push to get it started, but do not touch it while it is spinning.

Operation

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

Description

Build the circuit. Set the meter (M5) to the 1A scale and leave the fan off the motor (M1).

Assembly

WARNING: Moving par ts. Do not touch

the fan or motor during operation.

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3-Speed Motor (II)

Project #35

Educational Corner:

When wires from different parts of a circuit connect accidentally then we have a “short circuit”. You’ve probab

ly heard this term in the

movies; it usually means trouble. A short circuit is a wiring path that

bypasses the circuit resistance, creating a no-resistance path across the batteries. This will damage components 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 7 for examples of short circuits.

Electric Paths

WARNING: Moving

parts. Do not touch the motor during operation.

Push the press switch (S2) to turn on the motor and use the slide switches (S5) to control its speed. The meter measures the voltage across the motor. You may need to give the motor a push to get it started, but do not touch it while it is spinning.

Operation

Here you control the motor speed by diverting some of the current to the lamps (L4). Turning on the other lamps diver ts current awa y from the motor , reducing the voltage across it and slowing it down. This circuit is the same as project 34, except it measures the motor voltage instead of the circuit current.

Description

Build the circuit. Set the meter (M5) to the 5V scale and leave the fan off the motor (M1).

Assembly

Snappy says: the name “short circuit” refers to how the current through the circuit bypasses (jumps around) other components in the circuit. It is the “easiest” path through the circuit, it is not always the “shortest”.

Page 46

WARNING: Moving parts. Do not touch

the fan or motor during operation.

WARNING: Do not

lean over the motor.

3-Speed Motor (III)

Project #36

Educational Corner:

Turn off the slide switches (S5 position B) and get the fan spinning fast. Now turn on one of the other lamps (S5 position C) and watch how long it takes to light. The lamp takes a few seconds to get bright because it takes time to heat up the filament with a low current.

Electric Paths

-45-

Operation

Here you control the motor speed by div erting some of the current to the lamps (L4).

Description

Build the circuit and set the meter (M5) on the 1A scale.

Assembly

Push the press switch (S2) to turn on the motor (M1) and use the slide switches (S5) to control its speed. The meter measures the current through the motor. Be careful not to touch the motor or fan while it is spinning. You may need to give the fan a push to get it started, but do not touch it while it is spinning.

Snappy says: the current is lower when the lamp is bright, because the lamp filament has the most resistance when it is glowing hot.

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WARNING: Moving par ts. Do

not touch the fan or motor during operation.

WARNING:

Do not lean over the motor.

3-Position Switch

Educational Corner:

Some switches can be very complex, switching groups of parts on or off at once.

Electric Paths

Push the press switch (S2) to turn on the right lamp and use the slide switches (S5) to control the other parts. The meter measures the circuit current.

Operation

This circuit uses both slide switches to simulate a larger switch controlling many things.

This circuit has 3 lamps and 1 motor. When the press switch is pushed, 2 of these will always be on - you can’t set the slide switches to control more or less.

Description

Build the circuit and set the meter (M5) to the 1A scale.

Assembly

Snappy says: watch how the right lamp gets dimmer when the motor is turned on. The batteries can’t supply as much current as the motor wants, so the voltage drops a little.

Project #37

Page 48

WARNING: Moving parts. Do not

touch the fan or motor during operation.

WARNING: Do not

lean over the motor .

3-Position Switch (II)

Project #38

Educational Corner:

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.

Electrical current that is changing is called an alternating current, or AC. Because of this, the po wer from the electr

ic company is also called AC power. An electrical signal that is constant and unchanging is called a direct

current, or DC. The po wer from a

batter

y is also called DC power.

Electric Paths

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Push the press switch (S2) to turn on the right lamp (L4) and use the slide switches (S5) to control the other parts. The meter measures the circuit current.

Operation

This circuit uses both slide switches to simulate a larger switch controlling many things.

This circuit has 3 lamps and 1 motor (M1). When the press switch (S2) is pushed, either 1 or 3 of these will always be on - you can’t set the slide switches to control more or less .

Description

Build the circuit and set the meter (M5) to the 1A scale.

Assembly

A “blackout” occurs when part of a city is cut off from the power plants supplying it with electricity. The city will appear “black” from the air at night, since there are no electric lights on. This is usually due to accidents or stor ms, but is also done to confuse attacking bombers during war.

Page 49

A “brownout” occurs when power plants cannot supply enough current to a city during high demand, and must reduce the voltage below 120V. This sometimes occurs on hot days in summer when ever yone is using their air conditioners.

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4-Position Switch

Project #39

Educational Corner:

Solder

After Soldering

Set the slide switches (S5) to all positions and see what lights.

Operation

This circuit has four different lamp (L4) combinations, as if the two slide switches were acting like one four-position switch. The right lamp will always be on but its brightness varies. The other lamps may be on or off.

This right lamp is always on but there are four different paths to complete its circuit, because there are four slide switch combinations. The meter measures the current through one of the paths, see if you can find the others.

Description

Build the circuit and set the meter (M5) to the 1A scale.

Assembly

Actual electrical connections are made with solder, not snaps.

Solder is a special metal made mostly of tin that melts at relatively low temperature (about 500OF). Solder is applied and melted around a joint where a connection is being made; it creates a solid bond between the metals.

Before Soldering

Electric Paths

Page 50

Snappy says: Engineers refer to this switching combination as an AND sub-circuit (short for “this AND that”). It even has its own symbol.

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And

Project #40

Educational Corner:

Having to turn on a lot of 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 other slide switch could be a fuse box in your basement. Safety is very important in electrical wiring.

AND circuits are used in home security systems, where contacts across windows and doors are wired together in a series circuit like this one. Opening an y door or window breaks the circuit and triggers an alarm.

Use the switches (S2, S5) to turn on the lamp (L4).

Operation

The lamp will only light if there is a complete (“closed”) circuit. This means that the left AND right slide switches (S5) have to be on (position C). The press switch (S2) must be

on (pushed).

Description

Build the circuit shown.

Assembly

Electric Paths

AND Gate

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And NOt

Project #41

Educational Corner:

Suppose you wanted to monitor the voltage to a circuit, to see if the batteries were getting weaker. You could use the meter to measure the voltage, then read and record every hour. Then you have a series of numbers showing how the voltage was changing. Even if you watched the meter continuously, you probably wouldn’t remember what the voltage was a week later unless you wrote it down.

Representing an electrical signal as a series of numbers is digital electronics. Computers store and process almost all their inf

ormation as series of recorded

numbers. Sometimes it is easier to process

information as a digital series of numbers (computers), and sometimes it is easier to use a continuously changing voltage (AM

radios). Many products use both methods on the same information but at different times. The disadvantage of digital systems is that they are more complex since they have to store and process all the numbers . The advantages are that IC technology makes it inexpensive to store and process information, and digital systems are more protected from interference.

Electric Paths

Hold down the press switch (S2), then use the slide switches (S5) to turn the fan on or off.

Operation

If the press switch is on, then the fan will be off unless both lamps (L4) are on. In other words, the fan will be off if the left lamp AND the right lamp are NOT off.

Description

Build the circuit shown.

Assembly

WARNING: Moving parts.

Do not touch the fan or motor during operation.

WARNING:

Do not lean over the motor.

Snappy says: this type of switching combination is a NAND sub-circuit (short for “NOT this AND that”). It has its own symbol.

NAND Gate

Page 52

Snappy says:

this type of switching combination is an OR sub-circuit (short for “this OR that”). It has its own symbol.

OR Gate

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Project #42

Educational Corner:

Simple switching circuits like this are the basic building blocks of computers. Large arrays of simple sub-circuits like AND, NAND, OR, and others are used to add and multiply numbers together in the heart of advanced microprocessors. In computers, the switches used here are transistors controlled by other parts of the computer.

Electric Paths

Hold down the press switch (S2), then use the slide switches (S5) to turn the fan on or off.

Operation

If the press switch is on, then the fan will be on if either the left OR right slide switch is set to ON (position C) OR both slide switches are set to ON (position C).

The same type of circuit is used throughout your home, such as having several sensors controlling a security light.

Description

Build the circuit shown.

Assembly

WARNING: Moving parts. Do not

touch the fan or motor during operation.

WARNING: Do not

lean over the motor .

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Compass

Project #43

Educational Corner:

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. For centuries ships have used suspended magnets for navigation.

1 3

2 4

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.

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

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.

4. 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.

Operation

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

Description

Snappy says: 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.

Refrigerator

Door

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Project #44

Magnetic Fields

Educational Corner:

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

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 y our compass around the magnet and watch its pointer to see the magnetic field.

3. Shake the iron filings pack to spread the filings evenly. Mov e 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.

Operation

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Project #45

1. Place the iron core rod on one side of the magnet, making a chain. Hold/move the compass along this chain to see how the magnet’s magnetic field has been e xtended through the rod. You can also use the iron fillings pack to see the magnetic field.

2. Hold the compass close to the iron core rod, then remove it from the magnet. See how the compass reacts to this change to the magnetic field.

3. You can use the iron core rod to help the magnet pick up paperclips at a greater distance than normally possible.

Operation

Iron Extension

Educational Corner:

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.

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

Page 56

Snappy says: an electronic magnet is much better than an ordinary magnet because you can turn it on or off with a switch!

-55-

Electronic Magnet

Educational Corner:

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.

Iron Core Rod

Rubber Grommet

Project #46

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.

Operation

Pressing the switch turns on an electric current which transforms the electromagnet from an ordinary coil of copper wire into a magnet.

Description

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.

Assembly

Page 57

Iron Core Rod

Rubber Grommet

Note: the compass needle

may point opposite to how it’s shown here , depending on how you connected the jumper wires.

Project #47

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). Mov e 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.Mater ials 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.

Operation

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ElectroMagnet Magnetic Field

Snappy says: 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.

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ElectroMagnet Tower

Project #48

Educational Corner:

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.

Push the press switch (S2) sev er al 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. Remo ve a 1-snap from under each side of the electromagnet, then see how high the thin rod will go.

Part B: With the s witch 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.

Operation

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

Assembly

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

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

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Educational Corner:

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

transformer, 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. Transformers 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.

Iron Bar

Created Current

Original Current

Electric Paths

High Volta ge Power Lines

Transformer

120V House

Power Line

Power Plant

Typical

Transformer

ElectroMagnetic Suspender

Project #49

Set the slide switch (S5) to both positions and push the press switch (S2) sev eral times; compare how high the thin rod will go. Next, flip the switch slide back and f orth WHILE keeping the press switch pushed; the thin rod stays suspended but its height changes.

The lamps (L4) are used to reduce the current through the electromagnet, they will not light.

Operation

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

Assembly

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

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Electromagnet Direction

Project #50

Educational Corner:

Electric Paths

Airport metal detectors work by detecting a magnetic field change using electromagnets.

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.

For more fun: with the press switch pushed, try lifting the iron core rod out of the electromagnet with a paper clip.

Description

Push the press switch (S2). The meter shows a current is flowing and the compass needle is attracted to the electromagnet.

Note: in some cases your M5 meter may not be sensitive enough to measure the current. If your meter shows zero, switch to the 1mA setting, then switch back (the 1mA scale pre vents the compass from working here).

Now flip both slide switches (to position C) and push the press s witch again. The meter shows no current (because electricity flows in the other direction) and 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.

Operation

Build the circuit shown. Place the iron core rod in the electromagnet (M3), set the meter (M5) to the 1A scale, set the slide switches (S5) to position B.

Assembly

Page 61

Description

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.

Note: The magnetic field produced by the wire is very small. If the compass needle does not mo ve , check your batteries (B3), make sure y ou are not close to any iron objects, and make sure the red jumper is far from the compass.

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Wire magnet

Project #51

Build the circuit as shown. This circuit works best with new alkaline batteries.

Notes:

1. Place the red jumper wire near the 6-snap wire at the bottom of the circuit. K eep it as far a wa y from the compass as you can.

The 5-snap wire is connected on level 4 on the left side and at level 3 on the right side, o ver the compass. Make sure it is securely snapped.

Assembly

Set the slide switches (S5) so that the lamps (L4) are on. While watching the compass, flip both slide switches (reversing the current through the lamps). You should see the compass needle move a little - indicating a change in the magnetic field from the wire.

Operation

Educational Corner:

Electric Paths

In 1820 Hans Christian Oersted of Denmark noticed that an electric current affects a compass needle. This was the discovery of electromagnetism!

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magnetic Induction

Project #52

Educational Corner:

In separate experiments in the 1830s, Michael Faraday and Joseph Henry discovered that electric currents could be induced by changing magnetic fields.

This simple concept became extremely important to our society. Today , high pressure w ater or steam (heated by burning oil or coal) spins large magnets in coils to produce the electricity that runs our cities.

1mA

The meter shows an electric current even though no batteries are used. By moving the magnet near the coil, you hav e induced (created) a current in the circuit. You hav e made electricity from magnetism - an electric generator!

Battery-less flashlights and watches use this idea. By shaking the flashlight or watch, you mov e a magnet in it, which makes a current in a coil of wire, which powers the unit.

Description

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

If you hav e a more powerful magnet in y our home, use it in place of the Snaptricity

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

Operation

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

Assembly

Snappy says: many vending machines sort coins using magnetism, since fake coins will have different magnetic properties.

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Motor

Educational Corner:

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 mov e a magnet.

Inside the motor is a coil of wire mounted on a shaft. The motor shell has a magnet on it. When electr icity 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.

Project #53

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.

Electric Paths

Snappy says: the switches reverse the direction of electric current through the motor, changing the direction it spins. But the lamps don’t care which way electricity is flowing.

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

Description

Set the slide switches (S5) so that both are set to the same position (B or C), and push the press switch (S2). The lamps (L4) light and the fan spins.

Flip the slide switches to the other position and push the press switch again. The lamps still light and the fan spins the other direction.

Operation

Build the circuit as shown.

Assembly

Electromagnet

WARNING: Moving parts. Do not touch

the fan or motor during operation.

WARNING: Do not

lean over the motor.

Page 64

Project #54

Educational Corner:

How does the fan rise? Think first about ho w you s wim. 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 do wn by the weight of the full circuit.

-63-

Electric Paths

When the motor is blowing air up, it is a fan - just like the ones in your home. It will cool y ou 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.

Description

Set the slide switches (S5) to position B and push the press switch (S2). 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 slide switches to position C and push the press switch again. The fan spins the other direction and sucks in air from above and pushes it do wn to the table. If the fan is spinning fast enough, then it will rise into the air when you release the press switch. If you hold a sheet of paper near the motor, it will get sucked into the fan.

Operation

Build the circuit shown.

Assembly

Propeller and Fan

WARNING: Moving parts.

Do not touch the fan or motor during operation.

WARNING:

Do not lean over the motor.

Snappy says: 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.

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Back EMF

Project #55

Educational Corner:

The voltage/current produced by a motor when it is spinning is called its

Back Electro-Motive-F orce

(Back EMF); this ma y be thought of as the motor’ s electrical resistance. The motor’s

Front Electro-Motive-Force

is the force it exer ts in tr ying to spin the shaft. This circuit demonstrates how the Back EMF increases and the overall current decreases as the motor speeds up.

Electric Paths

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

Assembly

WARNING: Moving parts. Do not touch

the fan or motor during operation.

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.

Description

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 s witch again - the lamps stay bright as the fan speeds up.

Operation

WARNING: Do not

lean over the motor.

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Generator

Project #56

Educational Corner:

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.

Not only can electricity be transported over long distances, it can also be transported over 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.

Electric

Paths

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 electr

icity (a current in a coil in the motor). The meter shows how much current and voltage are produced b y the spinning shaft, with and without the fan.

Description

Set the switch to position B to get the motor spinning, then set it back to C and watch the meter to see how much voltage is produced.

Next, set the meter to the 1A scale and set the switch to B for a few seconds, then back to C and watch the current produced.

Now 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 .

Operation

BE SURE THE SLIDE SWITCH IS SET TO POSITION C BEFORE COMPLETING THE CIRCUIT. Build the circuit as sho wn, leav e the fan off the motor (M1). Set the meter (M5) to the 5V scale for now.

Assembly

WARNING: Moving parts.

Do not touch the fan or motor during operation.

WARNING:

Do not lean over the motor.

Snappy says: the most important aspect of electricity in our society - more important than the benefits of the Internet - is that it allows energy to be easily transported over distances.

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1mA

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Make Your Own Generator

Project #57

1mA

Educational Corner:

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.

Changing the direction you spin the shaft changes the direction of the magnetic field produced, which changes the direction of the electric current produced. This is known as Lenz’ s Law, after Russian physicist H. F. E. Lenz who studied electromagnetic induction in the 1800’s.

Magnet

Coil of Wire

Water Flow

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

This circuit is a true generator, using motion (and magnetism) to make an electric current.

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 .

Description

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.

Operation

Build the circuit and set the meter (M5) to the 1mA scale.

Assembly

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String Generator

Project #58

1mA

FOR ADVANCED USERS - ADULT SUPERVISION RECOMMENDED

If you can spin the shaft really fast then you may be able to light the lamp:

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

Description

Using the string, make a small loop at one end and put it on a prong of the motor (M1) top. Wind a few f eet of the string around the motor shaft (wind it so that pulling the string will spin the motor shaft clockwise). Then pull the string gently but fast, w atching the current produced in the meter . Get an adult to help with this if needed.

If you wind the string well and pull it fast, y ou can mov e the meter on the 1A scale. If not, you can use the 1mA scale to easily see the effect.

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.

Operation

Build the circuit and set the meter (M5) to either the 1mA or 1A scale.

Assembly

In many power plants, coal or oil is burned to heat water creating steam, which spins a turbine to make electricity .

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Motion Enhancer

Project #59

Educational Corner:

Electric Paths

There is a small current through the motor, this helps to spin in one direction but resists spinning in the other direction.

The slide switch adjusts the motor current, position B will not enhance/resist the spinning as much as position C.

Description

Give the motor shaft a spin with your finger. Notice how easily it spins, in both directions.

Now connect one end of the red jumper wire to the 3-snap wire, and hold the other end to the center spring in the battery holder (B3). Spin the motor shaft with your finger again, while still touching the red jumper snap to the spring in the battery holder. In one direction (cloc kwise) it will spin more easily than before, but less easily than before in the other direction (counter-clockwise).

Operation

Build the circuit. Leave the fan off the motor (M1). Set the slide switch (S5) to position C. Leave the red jumper wire off for now.

Assembly

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Holding Down

Project #60

Part B

Educational Corner:

Electric Paths

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

Description

Push the press switch (S2). The f an 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: Remove the motor and lamps from the circuit, then push the press switch again. Now the measured voltage is much higher, and the thin rod gets sucked up by the electromagnet.

Operation

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).

Assembly

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Make Your Own Electromagnet

Project #61

Educational Corner:

The iron core rod may remain magnetized for a while after you turn off the circuit. Magnets are usually made by subjecting iron bars to powerful magnetic fields. Some iron ores hold a magnetization for a long time, while other ores lose it as soon as the magnetizing field is removed. Heat and vibration can speed up demagnetization.

FOR ADVANCED USERS - ADULT SUPERVISION RECOMMENDED

Rubber Grommet

Iron Core Rod

Part B

Electric Paths

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 y ou 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.

Description

Push the press switch (S2) and move the iron core rod (with the red wire around it) around the compass and watch how it attracts the compass needle. The lamps (L4) also light when the switch is pressed.

Flip both slide switches to reverse the current. Push the press switch again and watch the compass to see how the magnetic field has changed.

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

Operation

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. Set the slide switches (S5) so both are in the same position (B or C).

Assembly

Snappy says: Your electromagnet (M3) is just like the coiled red wire except that it has many more loops. This gives it a stronger magnetic field.

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Relay

Project #62

Educational Corner:

When you need a relay f or a circuit, you usually b uy one instead of building one.

FOR ADVANCED USERS - ADULT SUPERVISION RECOMMENDED

Electric Paths

Relays are electronically controlled switches,

which allow a low-voltage circuit to control a high-voltage or high-current circuit. You may never ha ve heard of them, b ut they are used in many appliances in your home.

Electrical Symbol for Relay Actual Relay

This circuit is a relay, which uses one circuit to create a magnetic field that controls another circuit. The current through the electromagnet makes a magnetic field that attracts the nut-snap, which breaks the circuit to the lamp.

Description

Turn on the slide switch (S5, position C). The lamp (L4) should be on (if off, make sure the 4-snap is touching the 2-snap at D2 without being snapped there).

Push the press switch (S2) to turn on the electromagnet. This should r aise 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 B4 to the proper spring direction as shown, this may make the 4-snap move more easily.

Operation

Build the circuit shown. Three 3-snaps are stack ed together at base grid location D3-F3. Snap the 4-snap onto the 1-snap at B4, then place it so it lays on the snap at D2 (DO NOT SNAP IT ON). Place 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).

Assembly

Note spring

direction of

1-snap

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Relay (II)

Project #63

Educational Corner:

FOR ADVANCED USERS -

ADULT SUPERVISION RECOMMENDED

Electric Paths

This circuit is a variation of the preceding relay circuit.The current through the electromagnet makes a magnetic field that attracts the nut-snap, which breaks the circuit to the lamp.

Switch Y turns on the circuit and switch X controls the electromagnet. In part B, the lamp flashes briefly because it turns on faster than the electromagnet.

Description

Part A: Set the left slide switch (“X”) to position C and the

right slide switch (“Y”) to position C. The lamp (L4) should be on (if off, make sure the 4-snap is touching the lamp snap at F4 without being snapped there).

Set the left slide switch (X) to position B 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 y ou 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.

Par t B: Keep the left switch (X) on B and flip the right switch (Y) back and forth a few times, waiting a few seconds in each position. When the r ight switch (Y) is set to C, the lamp should come on for a f ew seconds , then turn off automatically . 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.

Operation

Build the circuit shown. Three 3-snaps are stacked together at base grid location E4-E6. Snap the 4-snap onto the 1-snap at D2, then place it so it lays on the snap at F4 (DO NOT SNAP IT ON). Place 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).

Assembly

The electromagnet pulls the 4-snap up to break the flow of electricity.

Note spring

direction of

1-snap

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Relay (III)

Project #64

Educational Corner:

Most home appliances operate at 120V. However, the electronic circuits used to control them (either automatically or by interfacing with people) operate at lower voltages (usually 5-15V). Relays allow these low voltage circuits to control high voltage machinery and appliances.

Electric

Paths

In a relay, the controlling signal and the signal being switched do not affect each other. This is done by using magnetism to open or close a mechanical switch.

FOR ADVANCED USERS -

ADULT SUPERVISION RECOMMENDED

This circuit is a variation of 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. Switch Y turns on the circuit and switch X controls the electromagnet.

Description

Set the left slide switch (“X”) to position C and the right slide switch (“Y”) to position C. Lamps B and C should be on (if off, make sure the 4-snap is touching the lamp snap at D3 without being snapped there).

Set the left slide switch (X) to position B to turn on the electromagnet. This should raise the 4-snap slightly, turn off lamp B, and turn on lamp A (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 B5 to the proper spring direction as shown, this may make the 4-snap move more

easily.

Operation

Build the circuit shown. At base grid location C1-C3, 3snaps are on levels 1 and 3 and a 2-snap is on le vel 4. Snap the 4-snap onto the 1-snap at B5, then place it so it lays on the snap at D3 (DO NOT SNAP IT ON). Place 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).

Assembly

Note spring direction of 1-snap

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Buzzer

Project #65

Educational Corner:

Electric Paths

FOR ADVANCED USERS -

ADULT SUPERVISION RECOMMENDED

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.

Description

Set the slide switch (S5) to position B to turn on the circuit. 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 1-snap at location A4 by 90 degrees, this may make the 4-snap move more easily.

Operation

Build the circuit shown. At base grid location B6-B8, 3snaps 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). Place 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).

Assembly

Snappy says: this circuit also works if you replace the lamp with the meter, use the 1mA scale. Since the circuit is sometimes on and sometimes off, the meter pointer will be vibrating.

Note spring

direction of

1-snap

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Buzzer (II)

Project #66

Educational Corner:

Snappy says: This circuit is similar to an electric bell. Instead of having a snap piece vibrating, there is a hammer hitting a bell.

Sound is a variation in air pressure created by a mechanical vibration. F or a demonstration of this , la y

one of your stereo speakers on the floor , place your hand on it, and turn up the volume . Y ou should f eel the speaker vibrate. Now place a piece of paper on the speaker; if the volume is loud enough, you will see the paper vibrate.

FOR ADVANCED USERS -

ADULT SUPERVISION RECOMMENDED

This circuit is 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.

When you hear buzzing, the current is very small but the meter (M5) needle will be vibrating, because the circuit is turning on and off rapidly . If there is no sound, then the current should be about 0.1A, due to the resistance of the electromagnet.

Description

Set the slide switch (S5) to position B to turn on the circuit. Adjust the position of the grommet until you hear a buzzing sound. Mak e sure the 4-snap lays centered on the snap at C4 (vibration tends to move it off-center); it should la y there without being snapped. The meter measures the current.

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 y ou still can’t get it to work, rotate the 1-snap at location A6 to the proper spring direction as shown, this may make the 4-snap move more easily.

Operation

Build the circuit shown. Two 3-snaps are stacked together at base grid location B2B4, two snaps are stacked together at grid location B4-C4, and three 2-snaps are stacked together at grid location C5-D5. Snap the 4-snap onto the 1-snap at A6, then place it so it lays on the snap at C4 (DO NOT SNAP IT ON). Place the nutsnap 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).

Assembly

Electric Paths

Note spring direction of 1-snap

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Reed Switch

Project #67

Build the circuit as shown. Place paper clips at base grid locations B1 and B3, beneath all the parts (this is used to raise the parts slightly). Snap the 6-snap at F5, then place it so it lays on the snap at B2 (DO NOT SNAP IT ON). Place the nut-snap on the 6-snap.

Assembly

Set the slide switch (S5) to position C to turn on the circuit, lamp A (L4) should be on.

Now hold the magnet about 0.1 inch above the nut-snap to attract it, this should turn off lamp A and turn on lamp B.

Moving the magnet up and down slightly above the n ut-snap should attract and release it, flipping the lamps on and off.

Operation

Description

This circuit acts as a reed switch, which is an electrical switch operated by a magnetic field. In this case, the magnet uses the reed switch to control the lamps.

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.

Educational Corner:

An actual normal open reed switch has two metal tabs inside a glass tube. A magnetic field brings the tabs together to complete a circuit. Here is a typical reed switch:

Electric

Paths

Glass Seal Glass Tube

Thick Wire Contacts

W . B . Elwood in vented the reed s witch at Bell Telephone Laboratories in 1936.

Paperclips

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Reed Switch (II)

Project #68

Educational Corner:

Electric Paths

This circuit acts as a reed switch, which is an electrical switch operated by a magnetic field. In this case, the magnet uses the reed switch to control electrical and mechanical devices (the lamps and thin rod).

Description

Set the slide switch (S5) to position B to turn on the circuit, the top lamp (L4) should be off and the bottom lamp should be on.

Now hold the magnet about 0.1 inch above the n ut-snap to attract it, this should turn on the top lamp, turn off the bottom lamp, and suck the thin rod into the electromagnet.

Moving the magnet up and down slightly above the nutsnap should attract and release it, flipping the lamps on and off and bouncing the thin rod.

Operation

Build the circuit as shown. Place paper clips at base gr id locations A7 and C7, beneath all the parts (this is used to raise the parts slightly). Snap the 6-snap at B2, then place it so it lays on the snap at B7 (DO NOT SNAP IT ON). Place the nut-snap on the 6-snap. Drop the thin rod inside the electromagnet (M3).

Assembly

Snappy says: a reed switch could be used in a door alarm. If a reed switch is in a wall and a magnet is on a door next to it, an alarm could be triggered if the door is opened.

Paperclips

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Cola Power

Project #69

1mA

If you want to watch this for a while without holding it, place the electrode between two

2-snaps as shown here.

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 that run your Snaptricity

kit or the larger battery in your family car. As some of the acid in the soda is neutralized, the current produced drops.

Description

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 awa y the soda used in this project. W ash off the electrodes.

Operation

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

Assembly

You can buy a cola-powered clock.

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Fruit Power

Project #70

Snappy says: you are converting chemical energy into electrical energy.

1mA

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, just like the “AA” batteries that run your Snaptricity

kit or the larger battery in your family car. As some of the acid in the fruit is neutralized, the current produced drops.

Description

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 awa y the fruits and vegetab les when you are finished with this project. Wash off the electrodes.

Operation

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

Assembly

If you want to watch this for a while without holding it, place the electrode between two

2-snaps as shown here.

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Water Impurity Detector

Project #71

1mA

If you want to watch this for a while without holding it, place the electrode between two

2-snaps as shown here.

The water in some areas is slightly acidic due to impurities in it. This ma y 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.

Description

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 hav e some distilled w ater, test it. It should hav e 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.

Operation

Set the meter (M5) to the 1mA scale and connect the jumper wires to it. Hold the metal snap of the jumper wires to the electrodes (red to copper), and place them in a cup of water.

Assembly

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Indian Rope Trick

Project #72

Do you feel like a magician?

Par t A : 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 str ing 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. Mov e it around in mid-air.

Par t B : Build the circuit shown and place the iron core rod in the electromagnet (M3). Secure the paper clip-string with a weight above the circuit, as shown. Push the press switch (S2) to pull the paper clip towards the electromagnet. Attract and release the paper clip by pressing and releasing the switch.

Operation

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Hypnotic Discs

Project #73

Build the circuit as shown. Cut out the red spiral pattern shown and tape it on the fan.

Assembly

Part A

Spin the pattern by briefly pushing the press switch (S2). You will see the most interesting effects when the pattern is spinning slowly. See if you can hypnotize someone into a trance.

Part B

Replace the pattern with the colored lines pattern shown. When the s witch 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 in your home and spin the disc slowly. As the speed changes, you may notice the lines first seem to mov e in one direction, then the y start moving in another direction. This effect is because the lights are blinking 60 times a second and the changing speed of the motor is acting like a strobe light to catch the motion at certain speeds. This doesn’t work with all fluorescent lights, due to differences in their circuitry.

Operation

Educational Corner:

When a person is hypnotized, some thinking capabilities of their mind are bypassed and they are in a new frame of thinking and perception. This can help them relax during medical procedures or other stressful times.

Try to make your own hypnotic disc!

WARNING: Moving par ts. Do not

touch the fan or motor during operation.

WARNING: Do not lean over the

motor.

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Project #74

You are getting sleepy...

Build the circuit as shown (the same as the preceding project). 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.

Assembly

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, mov e 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.

Operation

Description

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

WARNING: Moving parts.

Do not touch the fan or motor during operation.

Spin Draw

WARNING:

Do not lean over the motor.

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Snappy says: Years ago Indians would send messages to other tribes using smoke signals and a special code.

Morse Code

Project #75

Educational Corner:

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 _ _ _ _ _

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 above. 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 rev eal their presence to the enemy).

Operation

MORSE CODE

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Flying Saucer

The air is being blown down through the b lade 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 f aster when the batteries are new.

Description

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.

Operation

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

Assembly

WARNING: Moving parts. Do not

touch the fan or motor during operation.

WARNING:

Do not lean over the motor . Fan may not rise until switch is released.

Snappy says: This circuit is similar to project 54 but may launch the fan a little higher. Project 54 has the slide switches and more blue snap wires; together these add a slight amount of additional resistance to the circuit.

Project #76

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WARNING: Moving parts. Do not touch

the fan or motor during operation.

WARNING: Do not

lean over the motor.

Power Light Regulator

Project #77

Educational Corner:

Now set the top slide switch to position C (disabling the motor) and the bottom slide switch to position B (enabling the second lamp). While holding do wn the press s witch, flip the top slide switch to position B - the motor may need a push to start. Now release the press switch and push it again - the motor starts without a push.

Why can’t the motor start as easily when the lamps are already on? The lamps have more resistance when they are bright, and the motor needs a higher current to start spinning. When the lamps star t dark, more current flows until they warm up. This extr a current enables the motor to get going.

Electric Paths

Push the press switch (S2); at least one lamp (L4) lights and the meter reads the current. The slide switches (S5) add the other lamp and motor to the circuit.

Operation

Build the circuit and set the meter (M5) to the 1A scale. Leave the fan off the motor (M1).

Assembly

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RAISING THE BAR

Project #78

Educational Corner:

Electric Paths

Push the press switch (S2) to suck the thin rod into the electromagnet. The meter measures the current.

The slide switches (S5) adjust the rod height and meter current a little.

Operation

Build the circuit as shown. Drop the thin rod into the electromagnet (M3). Set the meter (M5) to the 1A setting.

Assembly

The slide switches add one or two lamps to the circuit, reducing the current through the electromagnet and meter.

Description

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WARNING: Moving parts. Do not touch

the fan or motor during operation.

WARNING: Do not

lean over the motor.

Electromagnetic Playground

Project #79

Educational Corner:

Electric Paths

Push the press switch (S2); either the lamps (L4) will light or the fan will spin, depending on the position of the lower slide switch.

Now , set the top slide switch to position C . When you push the press switch, the compass needle moves; when you release the switch, the compass returns to pointing toward the magnet. Hold do wn the press switch while moving the magnet closer to and then aw a y from the compass, and watch how the compass needle points.

The meter always shows the current.

Operation

Build the circuit as shown, set the top slide switch (S5) to position C, place the fan on the motor (M1), place the iron core rod in the electromagnet (M3), set the meter (M5) to the 1A scale, and lay the magnet on the base grid in the spot shown (red side toward the compass).

Assembly

The switches direct the electricity between the lamps, motor , and electromagnet. When activ ated, the electromagnet fights with the magnet for control of the compass needle.

Description

Congratulations,

you’ve finished!

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Notes

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OTHER SNAP CIRCUITS®PRODUCTS!

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Contains over 50 parts

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Page 92

1 1

3x22x2 6x1 5x14x1

Fan

Small Parts Bag

Black Jumper Wire

Red Jumper Wire

Iron Filings

Compass

Magnet

SCBE-75 Snaptricity®Block Layout

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

Call toll-free (800) 533-2441 or e-mail us at: help@elenco.com. Customer Service • 150 Car penter Ave. Wheeling, IL 60090 U.S.A.