Thames & Kosmos Electricity and Magnetism 620417 Experiment Manual

EXPERIMENT MANUAL

TITELSEITE U1

› › › SAFETY INFORMATION

Safety Information for Parents and Children

››› WARNING! Not appropriate for use by children under  years of age. There

is a danger of suffocation due to the possibility of swallowing or inhaling
small parts.

››› WARNING! Not suitable for children under  years. This product contains

small magnets. Swallowed magnets can stick together across intestines
causing serious injuries. Seek immediate medical attention if magnets are
swallowed.

››› Never experiment with wall outlets or the household power supply. Never

insert wires or other parts into wall outlets! Household voltage can be deadly.

››› You will need two .-volt AA batteries for the experiments. Due to their lim-

ited shelf life, these are not included in the kit.

››› Avoid short-circuiting the batteries while experimenting; they could explode!

››› Different types of batteries (e.g., rechargeable and standard batteries), or new

and used batteries should not be used together.

››› Do not mix old and new batteries.

››› Do not mix alkaline, standard (carbon-zinc), or rechargeable (nickel-cadmium)

batteries.

››› Only install batteries in the correct polarity direction. Press them gently into

the battery compartment.

Dear Parents,

This experiment kit will teach your children about electricity and magnets in
a simple and safe way. They will learn about and experiment with devices
such as light switches, electrical circuits, motors, permanent magnets, elec­tromagnets, and compasses.

As with any new science kit, you might have questions about the kit’s safety.
All electrical experiments are powered by two AA batteries (not included)
that need to be installed inside the included battery case. The experiments
are thus performed with the very low and safe electrical voltage of only 
volts.

This experiment kit meets U.S. and European safety standards. These stan­dards impose obligations on the manufacturer, but also stipulate that adults
should assist their children with advice and assistance with the experiments.
Tell your child to read all the relevant instructions and safety advice, and to
keep these materials on hand for reference. Be sure to point out that he or
she must follow all the rules and information while performing the
experiments.

››› Never recharge non-rechargeable batteries. They could explode!

››› Rechargeable batteries must only be charged under adult supervision.

››› Remove dead batteries from the kit.

››› Dispose of used batteries in accordance with environmental regulations.

››› Make absolutely sure that metallic objects such as coins or key chains are not

left in contact with battery terminals.

››› Do not bend, warp, or otherwise deform batteries.

››› Individual parts in this kit may have sharp edges or corners. Do not injure

yourself!

We wish you and your young electrician fun and success in your electric and
magnetic experiments!

› › › CONTENTS

Safety information .................................. inside front cover

Contents ................................................................................... 

Equipment ................................................................................ 

Tips and tricks for assembly ............................................... 

Troubleshooting ..................................................................... 

EXPERIMENTS

Electricity ................................................................................ 

We can no longer get by without electricity in our homes.
In this chapter, you will get to know a few of its basic
properties, and you will learn about all the things you
can do with switches and lights.

Electric Motor ....................................................................... 

Electric motors produce rotation from electric current.
You can also use your electric motor to tell the direction
in which current is flowing through your circuit.

Magnetism ............................................................................. 

How would you like to explore the secret powers of mag­netism? Dive into this mysterious world, which has been
put to use by early seafaring explorers and today’s high­tech engineers alike.

TIP !

You will find supplemental

information in the “Check it

out” sections on pages , ,

, , , , and .

Electromagnetism ................................................................ 

What does electricity have to do with magnetism? Find
out in the experiments in this chapter.



COMPONENTS› › › EQUIPMENT

Component Description Illustration

Presenting
the assembly
components!

This list presents brief descriptions
of all the components in the kit,
along with illustrations.

Battery case

Item No. 704484

Never directly connect these
terminals to each other. The
batteries and wires can heat
up and explode, not to mention
that the batteries will be
quickly used up.

Red light

Item No. 706415

Green light

Item No. 706417

Yellow light

Item No. 706416

Motor

Item No. 706414

This power pack supplies the electricity for the
experiments. Before starting the experiments,
you will have to install two 1.5-volt AA batter­ies (also known as penlight or LR6 batteries)
inside it, as indicated in the battery compart­ment. You can then obtain electric current
from the box’s two terminals.

Later on, electricity will light up this bulb.
That will show you that electrical current is
flowing.

This is just like the red light, except it’s a differ­ent color.

Again, this is just like the red light, except it’s a
different color.

When electrical current flows through it, the
motor and its yellow propeller will turn quite
quickly.

Two-way switch

Item No. 705055
Quantity: 2

Push button

Item No. 705054

Depending on the setting of the switch, one or
the other of two contact plugs will be electri­cally connected.

If you push the button, you create an electrical
connection between the terminals. But the
connection is only maintained as long as you
keep pressing it.



COMPONENTS

Equipment

Component Description Illustration

Connectors with 
terminals (X-shaped)

Item No. 705050
Quantity: 12

Straight connectors
with  terminals
(I-shaped)

Item No. 705051
Quantity: 4

Angled connectors with
 terminals (L-shaped)

Item No. 705052
Quantity: 2

Connector with
 terminals (T-shaped)

Item No. 705053

For connecting components.
The metal prongs of other
components such as the push
button are inserted into the
side slits. In the instructions,
they are called “X-connec-
tors” for short.

For connecting components
electrically. The two plugs
are electrically connected
to each other. In the instruc­tions, they are referred to as
“I-connectors” for short.

For the electrical connec­tion of components, but in a
way that guides the current
at an angle. Looks like an
“L,” hence referred to as an
“L-connector” for short in
the instructions.

For electrical connections.
The three prongs are electri­cally connected to each
other as indicated by the
white lines. In the instruc­tions, they are referred to as
“T-connectors” for short,
because their shape is simi­lar to a “T.”

Component Description Illustration

Red connecting wire
with plugs

Item No. 706428

Blue connecting wire
with plugs

Item No. 706429

Separator

Item No. 706078

Red alligator wire

Item No. 704486

Never insert the wire
into a wall outlet, or
connect it in any way to
the household current.
Electrical current from a
wall outlet is deadly!

For connecting the electronic
components. At the ends,
there are contacts that fit into
the green X connectors. Re­ferred to as “red connecting
wire” in the instructions.

Like the red connecting wire
with plugs, but in a differ­ent color. In the instruc­tions, it is referred to as

“blue connecting wire.”

An easy way of separating
assembled connectors,
lights, switches, etc. Simply
slide it between the compo­nents and pry them apart.

For connecting the electronic
components. At the ends, it
has alligator clips (so called
because they resemble the
jaws of an alligator). If you
squeeze the clips, they will
open up and you can clamp
them onto small metal con­nection prongs such as those
on the battery case, the
lights, or the motor. Called
“red alligator wire” in the
instructions.



COMPONENTS› › › EQUIPMENT

Component Description Illustration

Blue alligator wire

Item No. 704487

Bar magnet

Item No. 706423
Quantity: 2

Ring magnet

Item No. 706412
Quantity: 2

Like the red alligator wire,
but in a different color so you
can tell them apart more eas­ily. Called “blue alligator
wire” in the instructions.

A powerful magnet. The
different colors (blue, red)
mark the two poles of the
magnet. The north pole is
red, the south pole is blue.

With this magnet as well,
the red (north) and blue
(south) colors designate the
two magnetic poles.

Component Description Illustration

Small parts in pouch

Item No. 772180

Base

Item No. 706419

Arm

Item No. 706420

Various metal parts for the
experiments, such as screws,
nuts, washers, and colored
disks with a thin iron ring
that you can use for the mag­net games.

Belongs to the three-part
magnet hanger consisting
of a base, an arm, and a
cord with rings.

The L-shaped arm is part of
the three-piece magnet
hanger. It is inserted into
the horseshoe-shaped base.
The cord with rings hangs
on its hook.

Electromagnet

Item No. 706422



Unlike the bar magnets and
ring magnets, this only be­comes magnetic when elec­tric current flows through
it.

Cord with rings

Item No. 706421

Box of iron powder

Item No. 704449

Two rings tied together with
string, belonging to the mag-
net hanger. The smaller ring
is suspended from the hook
on the arm. The two bar
magnets are secured to the
larger ring.

Finely powdered iron in a
sealed container. This is
used for making magnetic
forces visible.

TIPS AND TRICKS

Equipment

Additionally required household items

> Two rulers (30 cm), pencil, cardboard, cardboard box, felt-tip pens, scissors,
paper, tape, metal prong fasteners from a folder, map of your area, paper clips
> Aluminum foil, metal pot, metal fork, cup, saucer, large water bowl, cooking
spoon, metal baking sheet, aluminum tealight candle holder, bottle, aluminum lid
from a jar, bottle closures
> Nail, sewing needles, file, sandpaper, piece of wood, handful of sand, various
coins, books, twine, textiles, plastic

Tips and tricks for assembly

It isn’t hard at all to assemble the electronic experimental setups in this kit.

• For each experiment, you will find a picture that shows exactly how to fit the
parts together.

• It is easiest to assemble parts that are equipped with plugs or prongs if you first
lay them out on a smooth table surface. Then slide the pieces together on the table,

so that the printed white lines meet up properly and the metal prong slides
smoothly into the X-connector hole.

• To disassemble the parts, simply insert the separator.

• Do not use force!

• After assembling a circuit, check it against the picture one last time before you
switch on the electric current.

Don’t worry:

If you start with the first experiments in this manual, you will soon have enough
practice handling the components that everything will become clear to you.

Foreword

This kit will help you explore two extraordinarily important invisible forces: elec­tricity and magnetism.

Of course, you know electricity by what it does — it makes light bulbs shine and
powers appliances such as television sets and vacuum cleaners. You may also
have seen a magnet and wondered why it attracts screws and other items made
of iron.

The kit has more than  experiments on these topics, and once you try them you
will know a lot more about electricity and magnetism than you do now. You will
find almost everything you need contained in the kit: switches, lights, a motor,
magnets, connector pieces and, for your power supply, a battery case in which
you will have to install two --volt AA batteries. You will also find a box for let­ting you see otherwise-invisible magnetic forces.

Troubleshooting

If something doesn’t work, try to isolate the problem:

• Does the assembly match what you see in the picture?

• Could the battery be dead? Check it with a bulb.

• Was a switch installed in the wrong position or the wrong way around?

• Could the light bulb be dead? Test it with the battery or try a different one.

• Is one of the connections loose? Push them all together again one more time.

The experiments are easy to perform, since precise drawings show you how to
assemble them, and everything is explained in the instructions as well. Stick to
the pictures as closely as possible and read the tips on the left side of this page.
That way, everything will work properly.

Have fun with the experiments!



Electricity

We use electricity every day. We only really tend to notice how

much we depend on it when we don’t have it. Electricity gives us

light and powers televisions and radios, washing machines and

refrigerators, electric ovens and stereo systems. Electricity from

batteries powers flashlights, transistor radios, and MP players.

You too, no doubt, have electric lighting in your room that you can

turn on and off with the flick of a switch. But how does it actually

work? How does this mysterious electrical current make light

bulbs glow? That’s what you’ll find out in the experiments in this

chapter.



EXPERIMENT 1 EXPERIMENT 2

Electricity

Circulating current

Your kit contains three different-colored light bulbs. Try lighting them up! The
battery case will supply the necessary current.

HERE’S HOW

Use the red alligator wire to connect one of
the battery case’s terminal prongs to one of
the prongs of the red light. Does the bulb
light up? No, it doesn’t.

Do you think the bulb might be dead? Try the
yellow or green one. Now try connecting
both of the light’s terminal prongs to the two
battery case terminal prongs. Break the con­nection somewhere. What do you see?

WHAT’S HAPPENING

Electric current always has to flow in

a circle, or circuit. If this kind of circuit

is broken in just one place, the flow of

electricity immediately stops — the

bulb will go out, or not light up at

all, if the light and battery case are

connected with just one wire.

Electric roller coaster

The wires run nice and straight. But will a wire also conduct current if it is
tangled up?

HERE’S HOW

Tie a loose knot in the red wire. Don’t pull
it too tight, or you might damage the wire!

WHAT’S HAPPENING

Next, assemble a closed circuit again with
the battery case, light, and the other alli­gator wire.

The bulb lights up just as

brightly as before, because

the current is so agile that

even a “roller coaster ride”

through multiple knots

won’t throw it off it at all.



EXPERIMENT 3

ELECTRONS

Reversed
connections

Electric current is
invisible. You can only
see it by its effects,
such as a glowing
light bulb or a turning
motor.

Current consists of a
flow of tiny particles
known as electrons.
They are even much
smaller than atoms,
and they can move
through something
like the metal in a
metal wire.

They flow through
your wires more or
less like water flows
through a pipe.

Does it make any difference which direc­tion the current flows through the light?
You can easily find out.

HERE’S HOW

Assemble a circuit again. The bulb will
light up.

Now remove the two wires from the
light’s prongs, turn the light unit around,
and reconnect the wires. Does the bulb
light up now?

WHAT’S HAPPENING

Yes, the bulb lights up just as well as

before, even though the current is
now flowing in the opposite

direction.

Light bulbs, such as the ones in your

kit, are among those electronic

components that work equally

well regardless of which direction

the current flows through them.

But as you will discover later on,

there are also components for

which the direction does matter.



EXPERIMENT 4 EXPERIMENT 5

Electricity

Prongs instead of alligator clip

In addition to the wires with alligator clips attached to them, you will also find
some wires in your kit with green cubes at their ends. Try seeing what you can
use them for.

HERE’S HOW

This time, assemble a circuit using the
wires with plugs at their ends.

You will have to push an X-connector onto
each of the wire’s plugs so that they can
be attached to the light and battery case.

WHAT’S HAPPENING

Then push the X-connector slots onto the
light and battery case prongs.

The bulb lights up. So you

can also use this kind of

wire for electrical

connections.

Green conductor

You will find other green connectors in your kit besides the green X-connectors.
Do you think you can use them to assemble a circuit without any wires at all?

HERE’S HOW

Connect up the components and the green
connectors exactly as you see in the
drawing.

Be sure that the prongs are inserted
securely into the slots.

WHAT’S HAPPENING

The bulb lights up as soon as

all the components are se-

curely connected.

The current flows through
the wires that are hidden in-

side the green connectors, as

shown by the white lines.

So you can also use the
green components for your

electrical connections.



EXPERIMENT 6

With half the force

ELECTRIC
VOLTAGE

The battery pushes
electrons through your
light like a water pump
pushes water through
a pipe. And just like a
water pump, the bat­tery creates “pressure”
to push the electrons
along.

In the language of elec­tronics, this “pressure”
is known as voltage. Its
unit of measure is the
volt (abbreviated “V”).

Each of your batteries
supplies 1.5 volts, and
when they are connect­ed together in a line
they add up to 3 volts.

Your battery case holds two batteries,
which join forces to power your circuits.
Do you think the bulb will light up if it
is supplied with current from just one of
them?

HERE’S HOW

Open the battery case cover and remove
one of the batteries.

Connect the battery case to the light using
the two plug wires and X-connectors. The
bulb won’t light up because the removed
battery was part of the circuit, which is
therefore no longer closed.

To close the circuit, connect together the
terminals in the empty section of the bat­tery compartment by using the red alli­gator wire. Now the bulb will indeed light
up, even if not nearly as brightly as it did
when you used two batteries.

WHAT’S HAPPENING



The experiment shows that a single

battery accomplishes less than two.

Now you also know why you al-

ways have to fill all the battery

compartments of a battery-pow-

ered device. Don’t forget to re-in-

sert the second battery for the next

experiments.

EXPERIMENT 7

Two bulbs,
half the brightness

If one battery does less than two, will it
also make a difference if they have to sup-
ply two lights with electricity instead of
one?

HERE’S HOW

Assemble a circuit with X-connectors and
one plug wire.

This time, insert two lights in a row so the
current has to flow through both, one
after the other.

Electricity

CURRENT
STRENGTH

Current strength, or

amperage, is a mea­surement of how many
electrons run through a
wire per second —
comparable to the
number of liters of
water flowing through
a pipe per second.

Current strength is
measured in amperes
(abbreviated “A”), a
unit of measure named
after the French physi­cist André-Marie
Ampère (–).

WHAT’S HAPPENING

Both bulbs light up, although less brightly than with one. This kind of arrange-

ment with two lights installed in a row is called a series circuit. It apparently lets

less current flow than when you use just a single bulb, which is why the light is

less bright. An electrician would say that the current strength is lower.

Only about one tenth of
an ampere flows
through your light,
while several hundred
amperes flow through
the engine of an elec­tric train.



EXPERIMENT 9EXPERIMENT 8

All yoked up Quick switch

Do you know another way connect two lights to a battery? Exactly: You can try
connecting each light directly to the battery terminals.

HERE’S HOW

Connect two of your lights to the battery
using four X-connectors and six
I-connectors.

The picture shows the simplest way to
hook up the circuit. How brightly do the
bulbs light up now?

WHAT’S HAPPENING

Now, both bulbs light up

with their full brightness.

If you follow the path of the

current, you will find two

circuits. Both are fed by the

same battery, and each

supplies current to one

light. This type of arrange-

ment is known as a paral-

lel circuit.

If you let the bulb shine for a long time, the batteries will get used up. On the other
hand, it can be inconvenient to have to keep reassembling the circuit. Luckily, there’s a
solution to this problem: a switch.

HERE’S HOW

In your circuit, replace one of the I-con­nectors with the two-way switch.

Now you can turn the light on and off by
pushing the orange-colored switch.

WHAT’S HAPPENING

Depending on its setting, the

two-way switch opens or

closes the two contacts

and, thus, the circuit. This is

very much like the way a

wall switch works when

you use it to turn the light

on or off in a room.



EXPERIMENT 10

Electricity

Switches in
lockstep

If you can arrange lights in a series, you
should also be able to do that with
switches. See how the current behaves
when you do that.

HERE’S HOW

Insert the two switches into the circuit
directly behind one another in series. This
way, you can more easily compare their
settings.

Try different settings for the two switch
buttons. How many different possible
combinations are there? And with how
many of them does the bulb light up?

WHAT’S HAPPENING

SWITCH SETTINGS

Switch 1 Switch 2 Light

left left off

right right lights up

left right off

right left off

The table shows that there are four possible combinations in all, and the bulb will

only light up with one of them.

Electrical engineers call this kind of arrangement of switches an AND circuit.

That’s because the light will only shine when switch  AND switch  are turned

on.

A lot of MP players will only work when their main switch is set to “On” and

you also press the start button — this is an AND circuit too.



EXPERIMENT 11

One or the other

SWITCH SETTINGS

Switch 1 Switch 2 Light

left left off

right right lights up

left right lights up

right left lights up



Of course, you can also hook up the two
switches in parallel. How does the current
behave when you do that?

HERE’S HOW

Assemble the illustrated circuit (figure ).

Try all the different switch settings again.
With which ones will the bulb light up
now?

Trace the course of the current with the
help of figure .



WHAT’S HAPPENING

Once again, there are four possible

combinations. But this time, the bulb

lights up with three of them and

stays off with just one.



This kind of parallel arrangement
of switches is called an OR circuit.

The bulb lights up when switch 

OR switch  is turned on. Only

when both are switched off will it

fail to shine (figure ).

EXPERIMENT 12

Morse code with

Electricity

light

Would you like to send secret messages to
your brother or sister or a friend next door?

One way to do that is by Morse code. This
is a code consisting of short and long sig­nals that you can send by radio or as puls­es of light. Each letter and each number is
transmitted as a certain sequence of short
and long signals.

HERE’S HOW

Assemble a circuit with push button and
light.

By pressing briefly or longer, you can
make the bulb light up accordingly. This
is how you transmit the Morse code
signals.

MORSE CODE

TIP!

Only let the current flow
for a brief time (a few sec­onds), or the battery will
quickly get used up.

WHAT’S HAPPENING

The push button closes the circuit

so the bulb lights up in matching

rhythm.

TIP!

If you really want to use
the circuit to send messag­es, you should get your­self a few meters of dou­ble-cable wire. Use the
alligator wires to hook up
the circuit so that the push
button and battery are
next to you but the light is
in another room (wherever
your friend is).

Another possibility is to
hold the light up to a win­dow so your friend can see
the light signals.

In the Morse telegraph ex­periment, you will build a
Morse station that will
also let you hear the
signals.



EXPERIMENT 13

Choice between red
and green





You have probably been asking yourself
what you can use the switch’s third termi­nal for. Now you’ll find out.

HERE’S HOW

Try the illustrated circuit. Turn on the
switch — what do you see?

WHAT’S HAPPENING

Depending on the position of the switch, the

red or the green bulb will light up.

When you activate the switch, one of the

two lights goes out while the other comes
on.

The setup contains two circuits — one
with the red (figure ) and the other with
the green light (figure ). Both are con-

nected at one end to the upper battery

contact. Depending on its setting, the
switch connects first one and then the

other light to the lower battery terminal.



This kind of red-green switch is very use-

ful. If you have a model train set, you

can use it as a railway signal. Or you
can use it as a signal to tell visitors

whether they are allowed to enter your

room or not.

EXPERIMENT 14

Your own traffic
light

Electricity

Of course, red and green are also the
colors that traffic signals use to tell
drivers or pedestrians whether they are
allowed to proceed through an inter­section or cross the street. Traffic lights
also use the color yellow. Would you
like to be able to control three differ­ent lights?

HERE’S HOW

Assemble the circuit exactly as shown
in figure . If you do it right, you can
choose whether to have the green, red,
or yellow bulb light up. Trace the
course of the current with your finger.

In the traffic lights used in some coun­tries, the yellow light can shine at the
same time as the red one, or at the
same time as the green one. This setup
can’t do that, but the one shown in fig­ure  can. In this one, the first switch
provides current to the green light,
while the other one controls the red
light, and you can use the push button
to switch on the yellow light whenever
you want.





WHAT’S HAPPENING

In the first circuit, the current

runs either to the green light or
to the second switch, which

switches it between the red and
the yellow lights.

In the second circuit, the two
two-way switches and the

push button are each connect­ed to one of the lights.



EXPERIMENT 15



Light from the end
of the hallway

In long hallways or in apartment building
stairways, you can usually turn the light
on or off from two different places. That
isn’t as easy to do as you might think. But
here’s a trick you can use.

HERE’S HOW

Assemble the circuit shown in figure .

Now you can turn the light on or off from
either switch.





WHAT’S HAPPENING

Follow the path of current for each of

the four switch position combinations.
Each switch can close the circuit in one

of its two possible settings — regard-

less of the setting of the other switch.

When it is connected to the red path,

the current then chooses the black or

the red route (figure ).

This method of connecting two
switches in a house or apartment is

known as a three-way switch.

EXPERIMENT 16

Conductors and
insulators

Up to now, you have used the wires and
green connectors to conduct electricity
from the battery case to the lights with-
out really thinking about it. But what
kinds of materials will conduct electrici-
ty, anyway? One thing you already know
is that air will not conduct electricity —
otherwise, you wouldn’t need any connec-
tors at all!

HERE’S HOW

Electricity

CONDUCTORS
AND
INSULATORS

Materials that conduct
electricity well are
called conductors.

Materials such as plas­tic, which will not con­duct electricity, are
called insulators.

Clamp the red alligator wire to one of the
battery terminals. Attach the light to the
other terminal using the X-connector.

Clamp the blue alligator wire to the free
prong of the light. When you press the two
free alligator clips together, the bulb will
light up.

Now, you can try connecting the two alli-
gator clips to all sorts of objects. If the
bulb lights up, you know that they con-
duct electricity.

Try it, for example, with a metal pot, a
wooden spoon, aluminum foil, a metal
fork, coins, teacups, paper, plastic, nails
and glass.

Your wires contain
copper inside them. The
plastic covering
prevents the current
from jumping from one
wire to another if they
happen to touch —
which would cause a

short circuit.

WHAT’S HAPPENING

Only objects made of metal will make the bulb light up. The

connectors also contain metal wire so that the current can flow

through them.



EXPERIMENT 17

Red light alarm

TIP!

If you can get a few
meters of dual-cable
wire from an electron­ics or hardware store,
you will be able to
install this alarm sys­tem on your door or
window.

WHAT’S HAPPENING

If a burglar opens the window,

the strips slide past each other

and make contact. The circuit is
then closed and the light comes
on briefly.

Real alarm systems usually

have an audible sound as well

as lights to indicate a break-in.

Most alarm systems are turned

off during the daytime, and

then turned on at night. When

the alarm system is turned on,
it is said to be “armed.”





Do you know what an alarm system is?
It’s a device that sends a signal whenever
an intruder opens a door or a window. You
can build your own simple alarm system
with a red light that comes on if someone
opens your window, for example.

HERE’S HOW

Make two solid strips of aluminum foil.
Clamp each inside a book in such a way
that it projects out. One book will repre­sent the window frame, while the other
represents the window sash (the window
itself).

Clamp an alligator wire to each of the
aluminum strips. Lead one wire to a bat­tery terminal, and the other to the red
light connected to the other battery termi­nal (image ).

Position the books in such a way that the
aluminum strips are close to each oth­er without quite touching. Now push one
book (the window sash) against the other,
so the strips briefly touch. What happens?

What if you want to be able to open the
window during the day without setting
off the alarm? In that case, install another
switch between the light and the battery
(image ). That way, you can turn the sys­tem on and off.



EXPERIMENT 18

Alarm when the
windowpane is
broken

What if an intruder breaks the win­dow instead of opening it? Or what if he
breaks in a plate glass window to steal
the window display from a store? What
would an alarm system look like that
was designed to set off an alarm in that
kind of situation?

HERE’S HOW

Electricity

TIP!



You can cut this kind of
thin aluminum strip
from the roll, secretly
install it and connect it
to the alarm system to
secure your windows,
doors, and drawers.

Assemble a circuit like the one shown in
image , with battery, light, two-way
switch, and alligator wire.

Cut a narrow,  cm-long strip of alumi-
num foil and clamp the free end of each
alligator wire to each end of the strip.

Switch on the alarm system: The red
bulb will light up.

Now imagine that a razor-thin aluminum
strip is attached to a windowpane. Then,
if the pane were broken, the strip would
tear. Try it with your strip — tear it. What
do you notice?



WHAT’S HAPPENING

As long as the aluminum strip is intact, the bulb will light up

when the alarm system is turned on, because the circuit is

closed. If it tears, the light goes out — this is the alarm signal
(image ).

Alarm systems like this are actually in use. In their case,

however, when the aluminum tears it sets off an audible

alarm or a releases a silent call to a security company.



CHECK IT OUT

Electrical network

This is what an electrician calls an arrangement of electronic
components connected together.

Electrical load

A load is something like an appliance that uses the electricity
supplied by a circuit. Small loads are things such as light
bulbs. An electric oven would be a somewhat larger
electrical load, and really big loads are such things as
the powerful engines in electric trains and streetcars.

Electrical circuit

Picture an enclosed water-filled pipe arranged in the shape of a
circle. A pump is installed in one part of the pipe. If the pump is
turned on, it sets the water into motion so that it flows around in
a circle through the pipe. In another location, there is a small wa­ter wheel that is turned by the flowing water, and imagine further
that this water wheel drives, say, a propeller on the out­side of the pipe. In this model of a cir­cuit, the pump corresponds to
your battery, which makes
electrons flow. The elec­trons move through the
wires, which correspond
to the pipes. And the water
wheel is like a light or a motor
— a device or appliance that takes the electrical ener-

Pump

Water wheel



gy supplied by the battery and converts it into light or move­ment. If you block the pipe at a certain location, the pump cannot
pump water any longer — the entire process stops. In the same
way, the flow of electrons will stop when the electrical circuit is
broken in any location.

Electricity

Circuit diagram

Electrical engineers have developed something known as a
circuit diagram, which offers a clear and simple way of repre­senting components and their connections. Each component is
shown as a symbol, or circuit symbol. The symbol for an elec­trical wire is particularly easy — a single line. When a wire is
thickened with a dot, it represents a place where two wires
are joined or connected.

Circuit diagram

Electrical network

Important circuit symbols

Battery

Two-way switch

Lamp

Push button

Motor

X-connector

L-connector

T-connector

I-connector



Electric Motor

In all sorts of places in our homes, in factories, and in vehicles, we
use devices that produce rotation from electrical current. These
kinds of electric motors provide power and movement wherever and
whenever they are needed. They are at work, for example, in mixers
and drills, vacuum cleaners and ventilators, CD players and computer hard
drives, lathes and countless other machines, and they power subway cars and
streetcars, locomotives and submarines. Even in a gasoline-powered car, all
kinds of electric motors are at work in fans, power windows,
and windshield wipers. Electric cars, of course, even use an
electric motor as their main drive source. You have an electric
motor inside your kit too.



EXPERIMENT 19 EXPERIMENT 20

Electric Motor

Sent spinning

If it’s called an electric motor, then electrical current should be able to make it
turn. Try it!

HERE’S HOW

Assemble a circuit with a switch. This
time, instead of a light, try installing the
motor with the fan mounted on top.

Turn on the motor with the switch.

WHAT’S HAPPENING

The electric motor converts

the electrical current into a

rotational movement — the

fan spins quickly.

Opposite direction

It made no difference to the light what direction the current flowed through it.
Does it make a difference to the motor?

HERE’S HOW

Connect the motor to
the battery case with
the alligator wire. Note
the rotation direction!

Now reverse the alligator wires
at the battery case. This will make the cur­rent flow the opposite direction through the
motor. How does it turn?

Now switch the wires at the motor termi­nals. What direction of rotation does the fan
have now?

WHAT’S HAPPENING

Unlike a light bulb, the motor

does have an obvious response

to the direction of current

flowing through it: If you re-

verse the direction of flow,

the fan’s rotation reverses as
well.



EXPERIMENT 21

BATTERY
POLES

Each of your baer­ies has two different­shaped terminals.

One of them is the
source from which
the current will flow
out into a circuit,
while the other is
where the current
flows back in.

These two terminals
are known as poles.
One is the called pos­itive pole (+) while
the other is called the
negative pole (-).

The baery case is
marked with these
plus and minus sym­bols as well.

If you reverse the
connections, the
current flows in the
opposite direction
through the circuit.

Quick change

Changing the direction of rotation by re­versing the wire clamps is a little clumsy,
of course. It would be great to be able to
do it with two simple flicks of a switch.

HERE’S HOW

Assemble the circuit with eight
X-connectors.

Try different switch settings and compare
the motor’s direction of rotation for each
one.

Trace the current path for each switch
setting.

WHAT’S HAPPENING

You can see how, for each switch

setting, the current flows in one di-

rection, in the opposite direction —

or not at all.

Accordingly, the fan rotates clock-

wise, or counter-clockwise — or

not at all.



EXPERIMENT 19EXPERIMENT 22 EXPERIMENT 23

Electric Motor

Current control

How can you check and make sure that a certain switch setting won’t result in a
short-circuit — that is, a direct connection between the two battery terminals?
The simplest way is to monitor the current flow with a light bulb.

HERE’S HOW

You can see that the circuit matches the one
in Experiment  (“Quick change”), except
in this case a light is attached directly to
one of the battery terminals.

On the other side, you will insert an I-con­nector to make the components fit together
again.

Try all the switch settings. When does the
bulb light up? Does anything occur to you
as you watch the brightness of the light
when the motor comes on?

WHAT’S HAPPENING

By lighting up, the bulb shows
you when current is flowing.

So you can be sure that when

it doesn’t light up, there’s no

circuit. At the moment that

the motor starts up, the bulb
is dimmer than it is after that

point. This shows that the

motor is consuming more

current at that moment.

Only once it’s running at full

speed does its electricity re­quirement drop again.

Motor or light

You can use the two-way switch to switch the current back and forth between
different loads. Try it with the light and the motor.

HERE’S HOW

Connect the light and the motor directly
to one of the battery terminals on one
side, and connect the other side of each
component to a different terminal of the
two-way switch.

Now you can choose whether to make the
bulb light up or the motor run.

WHAT’S HAPPENING

Depending on the setting of

the switch, the current will

run through the light or

through the motor.



EXPERIMENT 25EXPERIMENT 24

Motor plus light

You can also supply both the motor and the light with current at the same time.
You already tried a series connection in Experiment  (“Current control”), and
you found out that the light doesn’t light up very brightly with that circuit type.
But you know about a second wiring option — the parallel connection.

Motor at full brightness

Now the battery really has its work cut out for it. It will have to supply all three lights as
well as run the motor. Do you think it can handle all that?

WHAT’S HAPPENING

HERE’S HOW

This circuit is quite simple: Connect both
the motor and the light directly to the bat­tery terminals via the switch.



WHAT’S HAPPENING

With the parallel connection,

both loads get enough cur-

rent. So the bulb shines with

its full brightness, and the

motor turns fast.

HERE’S HOW

This circuit is just an extension of the par­allel circuit from Experiment  (“Motor
plus light”), with the two extra lights con­nected up with two extra connectors.

Turn on the current with the switch. Do
the bulbs light up? Does the fan turn?

Apparently, the battery has

no problem supplying all

four loads at the same time.

All three bulbs light up and
the motor turns. Of course,

the battery would get used

up much more quickly un-

der this kind of load than

when it has just one light to
power.

EXPERIMENT 26

Motor with double
switch

Sometimes, you might also like to be able
to turn a motor on and off from two dif­ferent locations. This circuit can do that.

HERE’S HOW

Assemble the circuit.

Try the different switch settings. Follow
the path of the current for each setting.

Figures  and , with their different cur-
rent paths indicated by broken lines,
should help you here.

Electric Motor



WHAT’S HAPPENING

It’s possible to turn the motor on or off from

either switch. You can see that we’re dealing

with yet another three-way switch here.





CHECK IT OUT

Electricity in nature

Electricity is a fundamental force of nature. Without it, our
world would not exist at all. After all, the atoms and mole­cules out of which all the world’s materials are composed are
held together by electrical forces. Without electricity, there
would be no stars or planets, no rocks, no living creatures.
Even electrons, those particles that make up electrical cur­rent, can be found everywhere in nature:

All atoms are made of tiny nuclei around which electrons
(usually a lot of them) are orbiting.

are the means by which the excess electrons leave the cloud.
In the process, the air along the lightning channel gets heated
explosively — to around , degrees Celsius, or six times
hotter than the surface of the sun! That’s what produces the
rolling thunder that accompanies the lightning flash.

Lightning

Lightning bolts are probably the showiest electrical phenom­ena in nature. Inside a thundercloud, there are areas with a
huge excess of electrons, and other areas where there are too
few. So, just like between the poles of a battery, there exists
electrical tension, or voltage, between these areas. In a thun­dercloud, though, the voltage doesn’t amount to just a few
volts. Often, it will be over  million volts. So it discharges
itself over and over again in the form of lightning bolts, which



How does a battery
produce electrical current?

You have been carrying out your electronic experiments using

Electric Motor

current from the two batteries in the battery case. But where
exactly is the energy in the batteries coming from?

Over  years ago, the physicist Alessandro Volta observed
that an electrical voltage is produced when two different

types of metal, such as copper and
zinc, are immersed together into a
salt solution.

Even today, batteries are usually
made of two metals connected via
an electrically conductive liquid or
paste. In this kind of battery, com­plicated chemical reactions take

place while the current is flowing,
with one of the metals gradually dissolving in the process.
The dissolution of the metal is what supplies the energy from
the battery. And that’s also why the battery becomes used up,
or “dead,” after a while.

Why is it that electricity can
be dangerous?

If electrical current flows through your body and blood, it de­composes the blood, with heat and toxic substances produced
in the process. On top of that, our nervous system (including
brain cells) works by the use of weak electrical signals. A
strong electrical current wreaks havoc on that system.

Because the body is a rather poor conductor of
electricity, electrical current only be­comes dangerous above a certain mini­mum voltage. A current of  volts,
which is what your battery case sup­plies, is harmless.

The  volts coming out of the wall
socket is quite another matter,
though. That can kill you!



Magnetism

In the experiments in this section, you will
be investigating the mysterious invisible
forces emanating from a magnet. And you
will learn how seafarers in earlier ages of
exploration used these forces to find their
way over seemingly endless expanses of
ocean.



EXPERIMENT 27 EXPERIMENT 28

Magnetism

Mysterious force of attraction

See how the magnets in the kit interact with the metal pieces.

HERE’S HOW

Spread out all the pieces from the kit’s
small parts pouch on the table.

Hold one of the cylindrical red-and-blue
bar magnets above them. Pay attention to
the distance between them and the mag­net. When do the metal parts jump up and
stick to the magnet?

Repeat the experiment with a ring magnet.

Now place the magnets on the table and
hold a screw a few millimeters first above
the bar magnet, and then above the ring
magnet.

WHAT’S HAPPENING

Apparently, magnets and iron

pieces can somehow sense

each other’s presence. If they

get close enough, they can at-

tract each other. Still, there

are differences among differ-

ent magnets: The bar mag-

net, for example, is stronger

than the ring magnet.

A love for
iron

We are surrounded by all kinds of mate­rials — glass, wood, paper, porcelain,
aluminum, and so on.

Will magnets also have an effect on all
those other materials? Find out by
experimenting with various items from
your home.

CAUTION!

Do not touch diskettes, compact disks, audio
or video tapes, credit cards with magnetic
strips, computers, or mechanical watches
with your magnets. The sounds, images, or
other data stored on them would be irretriev­ably erased, and the watch might not work
properly any longer.

HERE’S HOW

Walk around your house with the bar magnet
and test it on various objects to see if it attracts
them.

In particular, try testing pots, nails, glass, cups,
aluminum bottle caps, paper, baking sheets,
coins, cutlery or silverware, furniture, needles,
and paper clips.

WHAT’S HAPPENING

The magnet will not respond to

objects that have no iron at all.

On the other hand, it can sense

iron even if the iron is hidden

under a layer of plastic.

So you can use a magnet as an

“iron detector.” If you have a

wire or paper clip coated in

plastic, for example, you can
use the magnet to tell whether

there is iron inside.



EXPERIMENT 30EXPERIMENT 29

Scrap metal separator Intimate attraction

Iron and steel are important raw materials that are hidden inside all sorts of
everyday things. Still, a lot of iron-containing objects end up in the trash. With
the help of a magnet, you can separate those objects from the rest of the trash in
order to recycle the iron.

WHAT’S HAPPENING

Piece by piece, the metal ob-

HERE’S HOW

Pour a handful of sand into a bowl. Mix
the small metal pieces into the sand.

The sand will represent the non-magnetic
trash. Now, try digging around in the sand
with the bar magnet.

jects will get stuck to the bar

magnet. In fact, powerful

magnets really are used at

trash collection facilities to

separate iron and steel

parts from other trash.

Then they are melted down

again and reprocessed into

new iron parts.



Apparently, magnets are capable of monitoring their surroundings, sensing the presence of
iron, and pulling it close with invisible arms. How far do you think those arms might reach?

WHAT’S HAPPENING

The strength of the magnetic

HERE’S HOW

Lay a -cm ruler on the table, and place a
screw precisely on the zero mark.

Now slowly slide the bar magnet toward the
screw, blue end in front, starting from around the
-cm mark. At what distance (in millimeters)
does the screw tip over due to the magnet’s force
of attraction and stick to the magnet?

Try performing this experiment with the ring
magnet as well.

force depends a lot on the dis-

tance. At a greater distance,

the force is weak, but as you
get close it quickly increases.

You can use the screw and the

ruler to compare the strength

of various magnets and their
different sides. The ring mag-

net will be weaker overall.

EXPERIMENT 31 EXPERIMENT 32

Contagious magnetismPenetrating effect

Magnetism

The force of a magnet can evidently penetrate air, because otherwise it wouldn’t
have been able to sense the screw in Experiment  (Intimate attraction). But can
a magnet also “see” through other materials?

HERE’S HOW

Move various objects between the magnet and the
screw to test whether you can still feel the force of
attraction.

Of course, the objects shouldn’t be thicker than a
few millimeters, since otherwise the distance
alone might prevent you from feeling anything.

Try it with plastic wrap, aluminum foil, a thin­sided cup, cardboard, paper, fabric, and an iron
baking sheet.

WHAT’S HAPPENING

The magnetic force apparent-

ly penetrates all these mate-

rials without any problem,

even the metal ones. The

only exception is the iron

baking sheet.

Is a magnet capable of altering the iron that it attracts? It may look no different
from the outside, but do you think it might have acquired special properties?

HERE’S HOW

Take a screw in your hand and see if you can use it to
attract any of the other iron pieces from the pouch. In
fact, you won’t feel any effect.

Suspend the screw from the bar magnet and then
touch it against other iron pieces from the pouch. They
will be attracted to it.

If you remove the magnet from the screw, the other
pieces will fall off again.

See how many of the little pieces the screw can hold!

WHAT’S HAPPENING

The magnet does in fact

change the iron in the screw,

by turning it into its own lit-

tle magnet. But this change

is only sustained as long as

the magnet sticks around.

As soon as the magnet has

moved far enough away,

the magnetic power of the
screw disappears as well.



EXPERIMENT 34EXPERIMENT 33

Magnetic flowers

You can put magnetic forces to use by having them make parts stick to each
other temporarily — without using any glue. Of course, the parts will have to
have something made of iron, such as the rings around these plastic disks.

HERE’S HOW

Here’s where your imagination has to
get in on the act. Try composing inter­esting shapes out of the four magnets
and the colorful disks. How about a
flower, for example?

WHAT’S HAPPENING

By using their force of at-

traction to hold the iron

tight, the magnets keep the

shapes from falling apart.

Magnetic fishing

Here’s an age-old game — angling for iron “fish”
with the use of a magnet. You and your friends
will enjoy this.

TIP!

You can use a felt-tip pen
to mark the disks with dif­ferent point allocations.

HERE’S HOW

Take a -cm piece of twine, and tie one end
tightly to a ring magnet and the other end to the
handle of a cooking spoon. This will be your
fishing rod.

Spread the plastic disks across the bottom of a
box. Now, without looking into the box, take
turns fishing. If you lift up the fishing rod with­out having caught anything, you have to pass it
to your neighbor. If you catch something, take
another turn.

The winner is the one who has the most plastic
disks at the end of the game, or the most points.

WHAT’S HAPPENING

The magnet attracts the iron

rings around the disks. But

because the ring magnet is

not very strong, the disks

can easily fall off again,

which makes the game

more challenging and more

fun.



EXPERIMENT 35

Centers of force

Magnetism

You have probably noticed that the magnetic force is not equally strong in all
parts of the magnet. Now it’s time to investigate this a little more closely, using a
plastic disk with an iron ring as your test object.

WHAT’S HAPPENING

HERE’S HOW

Bring the disk close to the bar magnet
and move it slowly around the magnet.
Where do you feel the force of attraction
most strongly?

Let the disk be attracted by the magnet.
Where does it stick to the magnet?

Repeat the experiment with the ring
magnet.

In fact, any magnet has two

locations where its magnetic

force is greatest. These are

called the “magnetic poles.”

With the bar magnet, the

poles are at the ends, and the

magnetic force is much

weaker in the middle. With

the ring magnet, it’s the ring-

shaped surfaces that repre-

sent the poles.

Magnets…

…can be made in all kinds of shapes. There are bar and ring magnets like the
ones in your kit, but magnets also exist as tubes, disks, powders, flexible films,
and as lots of other types as well, depending on how they are to be used.

But you can always tell a magnet apart from similarly shaped iron pieces, sim­ply by bringing another magnet close to it. Start by turning one of the magnet’s
ends toward the unknown object, then turn it around and bring the other end
close. If the object in question is a piece of iron, you will feel a force of attrac­tion with both ends. If the object is itself a magnet, it will be pushed away when
one of the ends of the first magnet is moved close to it. You will investigate this
phenomenon in the next experiment.



EXPERIMENT 36

Magnetic friends and
foes

THE POLE
COLORS

The red and blue
colors are just for
purposes of identifi­cation, of course.

The reason the poles
behave differently
has to do with certain
properties of their
atoms, which are the
smallest particles in
the magnetic mate­rial.

You have already tested a lot of materials to see how
they behave in response to magnets. But how do
magnets behave with each other?

HERE’S HOW

Hold the two bar magnets close to each other.
What do you feel?

Turn one of the magnets around. What do you
notice? Pay attention to the colors of the ends!

Repeat this experiment with the ring magnets.
Then try seeing how a ring and a bar magnet
respond to each other.

WHAT’S HAPPENING

While the two poles of a magnet will behave

identically toward pieces of iron, they do not be­have identically toward other magnetic poles.

Two poles of the same color will repel each oth-

er, while different-colored poles will attract
each othe r.



To tell them apart, one pole is called the north
pole, while the other is called the south pole.

Two north poles or two south poles will repel

each other, while unlike poles will attract.

N S N S N S N S

In your magnets, the red end is the north pole,

while the blue end is the south pole.

EXPERIMENT 37 EXPERIMENT 38

Insufferable twinsFloating on magnetic pillows

Magnetism

Instead of moving on wheels, magnetic levitation trains float a few millimeters
above the track. That helps them stay quiet and vibration-free even as they reach
speeds of over  kilometers per hour. The secret lies in using the repelling
forces of magnets to help them float on a cushion of air. Can you do the same
trick with your ring magnet?

WHAT’S HAPPENING

The magnets don’t touch each

HERE’S HOW

Stick a pencil pointed-end-first into the kit
box’s Styrofoam.

Drop one of the ring magnets onto the
pencil.

Place another ring magnet on top of it,
with two surfaces of the same color fac­ing each other.

other at all. The upper one

floats above the one below it as

if held up by the hand of a

ghost.

That’s because the two ring

magnets will repel each other

when two poles of the same

type are facing each other. The

pencil keeps the upper mag-

net from slipping to the side.

In Experiment  (Contagious magnetism), you turned a piece of iron into a magnet.
Now that you have learned something about magnetic poles, it’s time to investigate this
a little more closely. What happens when you bring two similar pieces of iron, such as
the two disks with a hole in them, up to one of the poles of the magnet?

WHAT’S HAPPENING

The two washers will imme-

diately tip away in opposite
directions as soon as they

touch the bar magnet. The
bar magnet is transforming

the washers into magnets.

But they have their like
poles turned toward each

other — north pole (N) to-

ward north pole, south pole
(S) toward south. And like

HERE’S HOW

Place the two washers next to each other on the red
north pole surface of the bar magnet.

Hold them tight against each other with your fingers.
What do you feel?

You can perform the same experiment with the same
result on the blue south pole.

poles repel each other.

So when you hold them

tight, you can easily feel
the forces of repulsion be-

tween them.



EXPERIMENT 39

WHY DOES A
MAGNET
ATTRACT IRON,
OF ALL THINGS?

Disappearing poles

Each of your magnets has a north pole
and a south pole. Do you think you could
ever find just a north or a south pole by
itself, or do they only come in pairs?

HERE’S HOW

It’s because iron con­sists of countless tiny
magnets, due to its spe­cial atomic structure.

These so-called molec­ular magnets are nor­mally all jumbled up,
so their individual mag­netic forces cancel each
other out.

When they happen to
get close to another
magnet, they all line up
in the same direction.

That’s how a piece of
iron will temporarily
turn into a magnet as
well — and these two
magnets will attract
each other.

Attach the two bar magnets to each other
by bringing the opposite poles together.

Now test to see where the areas of stron­gest magnetic force are. What can you
determine?

Pull the magnets apart and test them
again. Repeat the experiment with the
ring magnets.

WHAT’S HAPPENING

Two magnets connected together
behave just like one single magnet

with two poles. In the area where

they touch, on the other hand, their

magnetic force disappears.

When you pull them apart, though,
it reappears. The same thing hap-

pens when you actually saw a

magnet in half: You get smaller

and smaller magnets, each with

two poles.



EXPERIMENT 40

Magnetic force
made visible

It’s kind of a shame that you can’t see
magnetic forces. But there’s a trick for
making them visible — by using the iron
powder from the plastic box.

HERE’S HOW

Place the two touching bar magnets flat
on the table. Spread out the iron powder
fairly evenly in the box and hold the box a
few millimeters above the magnets
(which creates clearer patterns than
when you hold the magnet directly
against the box).

Magnetism





Tap gently on the box. The iron particles
will form a picture, as if painted by the
hand of a ghost (figure ).

You might have to perform this experi­ment a few times before you get the hang
of making a really nice-looking pattern.

Stand the bar magnet upright (figure )
and repeat the experiment. How does the
picture look now?

Also try seeing what kinds of patterns the
ring magnet makes (figure ).

Continued on the next page…





EXPERIMENT 40

HERE’S HOW IT CONTINUES





TIP!

When unlike poles are
facing each other, you can
create an actual bridge of
iron powder from one to
the other. That won’t work
with equal poles.

MAGNET FIELD

You can picture magnetic force as lines projecting out from one magnetic pole, run­ning through the surrounding space, and then re-entering the other pole. These so­called magnetic lines of force are just a simple conceptual model, of course. In reality,
a magnet is altering the space around it by giving it the property of being able to exert
force on pieces of iron. Physicists call this kind of altered space a field. So there’s a
magnetic field all around the magnet, with the strength of the field falling as you get
farther away from the magnet.

Secure the bar magnets a few millimeters
apart on the table and see what kinds of pat­terns they form (figure ).

Now hold the two bar magnets against the
top of the box (figure ). Of course, they will
attract some of the iron powder.

WHAT’S HAPPENING

As the iron particles show, the mag-

netic force seems to pour out of the
poles and follow an arching path

back to the opposite pole, with that

path reaching a few millimeters out
into the surrounding area.

That is because the iron particles
themselves turn into little magnets

when they are close to another
magnet.

You already know about this from
Experiment  (Contagious mag-

netism). The particles orient them-

selves according to the poles of
the magnet, and stick together in

chains. That’s how the pattern is

created out of thousands of tiny
magnets.



EXPERIMENT 41 EXPERIMENT 42

Dancing magnetsHanging magnets

Magnetism

As you have already seen in
several experiments, mag­nets have a definite
response to other magnets.
You can use this knowledge
to build a very sensitive
detection device for mag­netic forces.

TIP!

Keep your other magnets
at least one meter away,
so they don’t interfere
with your experiments!

HERE’S HOW

Mount the hanger arm on the base. Hang the
cord with rings from the hook by the small
ring. Insert the two bar magnets into the large
ring so they stick tightly to each other.

Wait for the bar magnet to stop swinging.
Now you can move one of the ring magnets
toward it and test the sensitivity of your
device.

WHAT’S HAPPENING

Because the magnets are sus-

pended in a way that lets

them move freely, they can

even react to weak magnetic

forces by turning their at-

tractive pole toward the oth-

er magnet.

The bar magnet dangling on the
string is extraordinarily mobile.
That makes it handy for this fun
experiment.

HERE’S HOW

As you did in the last experiment,
suspend the two bar magnets with
the cord from the hanger arm.

Now move the ring magnet past
the suspended bar magnet from a
certain distance away.

If you coordinate the movements
of the ring magnet and the pair of
bar magnets skillfully enough, you
will be able to get the bar magnets
to rotate rapidly.

WHAT’S HAPPENING

The sideways movement of the ring magnet

is transferred to the bar magnet via the

magnetic field, and makes the bar magnet
start rotating. If you keep giving it a push

with the ring magnet at just the right mo-

ment, the rotation gets faster.

This is the same principle by which elec-

tric motors work: They contain magnets
that are set into a spinning motion by

other magnets.



EXPERIMENT 44EXPERIMENT 43

Improved penetration test

In Experiment  (Penetrating effect), you tested various materials for their abil-
ity to let magnetic force pass through them. Now, with your sensitive detection
device, you can perform this test much more accurately.

HERE’S HOW

Tape the ring magnet to a bottle and guide it
close enough to the bar magnet pair hanging
from the hanger arm to make the bar mag­nets turn noticeably toward it.

Leave the bottle in this position and move
various materials between the magnets —
glass, porcelain, wood, plastic, your hand,
metals, and so on. Even fairly large objects
will be able to fit between them now.

WHAT’S HAPPENING

Thanks to the high sensitivity

of your device, the test is

much more convincing than

the first experiment with the

screw. Still, the result is pret-

ty much the same: All the

materials except for iron will

let the magnetic force pass

through unhindered.

Intensified magnetic force

Two horses can pull more than one, and two batteries will light
up a bulb more brightly than one. Do you think that two mag­nets together might be stronger than a single one alone?

HERE’S HOW

Push the zero marker of a ruler ( cm) under
the pair of bar magnets. Wait for the magnets
to stop moving.

Slide a ring magnet slowly along the ruler
toward the bar magnets. Note the distance at
which the magnets react.

Now stick the two ring magnets together with
their unequal poles facing each other. Slide
them toward the bar magnets again. When do
the bar magnets react?

Repeat the experiment, except this time push
the ring magnets together with their equal
poles facing each other.

WHAT’S HAPPENING

Two magnets stuck together are no-

ticeably stronger than one, and they

will make the bar magnets move from
a greater distance away.

On the other hand, the magnetic

force is greatly reduced when you

push the ring magnets together with

their equal poles facing each other.

Then, you can bring the ring mag-

nets quite close before the bar mag-

nets respond.



EXPERIMENT 45

Magnetism

Magnets in
competition

You can also use your sensitive hanging
magnet device to compare the strengths
of two magnets.

HERE’S HOW

Assemble the hanger device with cord and
bar magnets, and wait until the “long”
bar magnet stops moving.

Now set down two rulers ( cm) so that
they form a right angle. The bar magnet
should point to the exact center of this
angle.

To be able to see this position easily,
rotate the hanger base so that the magnet
is suspended exactly in the middle of it.

Now you can slide both ring magnets
along the rulers toward the hanger. To let
you see a difference, hold one magnet ver­tically and the other horizontally. If you
have other magnets, of course, you can
try them too.

Push the first magnet forward until you
see a slight reaction from the bar magnet.
Then push the other magnet along until
you see the bar magnet regain its earlier
position.

TIP!

You shouldn’t get much closer
than a few centimeters, since it
will falsify the measurement if
you get that close.

WHAT’S HAPPENING

You can use this method to compare
magnetic forces with a great deal of pre­cision. You just have to be sure that the

same pole is always turned toward the

bar magnet, or you’ll be comparing ap-

ples with oranges.



EXPERIMENT 47EXPERIMENT 46

Birth of a magnet

In Experiment  (Contagious magnetism), you saw how a piece of iron can turn
into a magnet when it is touched by a magnet. Unfortunately, the magnetic
power disappears as soon as the iron and the magnet are separated. But that
isn’t true for all iron objects.

TIP!

Be sure to keep the
magnetic needle in a safe
place, since you’ll be
needing it for other
experiments.

HERE’S HOW

Mysterious behavior

Researchers tend to have excellent powers of observation. Are you a good observer?
Let’s find out!

Start by using the iron pieces to test the
needle for magnetism. It will presumably
be very weak at best.

Now stroke the blue pole of the bar mag­net  to  times across the needle,
always in the same direction.

Test the needle again. What do you find?



WHAT’S HAPPENING

Now the needle really does act

like a magnet, even if only a

weak one.

The needle is made of steel,

which is a kind of iron that has

been treated in a special way.

When you magnetize steel, it

retains its magnetic power.

HERE’S HOW

Place the hanger device, with the bar magnet sus­pended from it, in various locations around your
home. Wait each time for the magnet to stop moving.
Watch carefully. Do you notice anything?

Look for a notable landmark some distance away
(say, a tall building or a mountain) in the direction in
which the magnet is pointing. Also try going outside
to see what direction the magnet points.

WHAT’S HAPPENING

Whether you’re inside or

outside, the magnet always

points in the same direction.

EXPERIMENT 48 EXPERIMENT 49

Remote-controlled magnetFloating magnets

Magnetism

Do you think the fact that the bar magnets always point in the same direction
might have something to do with the hanger device or maybe the cord? It’s easy
to check by setting something else up that will still let the magnets move
freely. How about having them float on water?

HERE’S HOW

Fill a bowl with water.

Set the stuck-together bar magnets on a saucer
and let your “boat” float freely (don’t let it get
caught against the edge). After a few seconds,
the bar magnet, and the saucer along with it,
will turn in a certain direction.

Turn the bar magnet in a different direction.
What do you notice?

Perform the experiment again with two ring
magnets standing upright.

WHAT’S HAPPENING

Even the floating magnets

prefer a certain direction.

Apparently, they feel the same

external influence as the
hanging magnets.

You could test your magnets

almost anywhere: They

always have the same

preferred direction. Why? See

the next experiment.

It would be interesting to figure out what direction this is that seems to be so important
to the magnets. To do that, try finding your home’s location on a map of your area.

N

S

HERE’S HOW

In Experiment  (Mysterious behav­ior), you looked for a notable land­mark in the direction in which the
magnet was pointing. Look for this
landmark on your map, along with
your home.

Draw a line with a pencil between the
two locations. Do you notice
anything?

WHAT’S HAPPENING

The line should lie parallel to the left and right

edges of the map. That’s due to the conven-

tional way of representing things on a map:

Maps are drawn with the north at the top,

south at the bottom, west to the left, and

east to the right.

So your line indicates that the bar magnet

settles into in a north-south direction. In

other words, it is acting like a compass

needle.



EXPERIMENT 50

ALWAYS TO THE
NORTH

A compass needle, as
you already learned, is
a tiny magnet. It ori­ents itself according to
the direction of Earth,
since Earth itself is a
magnet.

Earth behaves as if
there were a giant bar
magnet wrapped in­side its interior, with
one end near the North
Pole, and the other end
near the South Pole.

In reality, of course, it
isn’t really a gigantic
permanent magnet
that produces Earth’s
magnetic field. The
field is actually
caused by powerful
electrical currents
flowing through
Earth’s metallic core.

N

N

S

WHAT’S HAPPENING

If the polystyrene foam floats freely, the nee­dle always points in a north-south direction.

Slender arrows and needles let you detect a

northerly direction more precisely.

Magnetic needle

The bar magnet is only somewhat useful
as a compass, since its shape won’t let
you read the direction very precisely. But
there’s a better option. Try your hand at
making a replica of one of the earliest
compass models — a floating compass.

HERE’S HOW

Fill a bowl with water. Break off a piece of
polystyrene foam, as flat as possible,
from the kit’s parts tray, and let it float in
the bowl.

Once it is floating properly, insert the
magnetized needle from Experiment 
(Birth of a magnet) horizontally through
part of the polystyrene foam piece, and
let it float freely in the middle of the
bowl. What do you notice?

How does your floating compass react
when you bring the ring magnet or bar
magnet close to it?

N



In fact, early compasses really were made

out of a magnetized needle and cork float-

ing in a bowl of water marked with a scale.

S

S

CHECK IT OUT

The word magnet…

…comes from the name of the ancient city of Magnesia in Asia
Minor. That’s where people found chunks of an unusual,
heavy material with a
strange property of attract­ing pieces of metallic iron.
Today we know that this was
the kind of iron ore we call
magnetite.

Compass

Thousands of years ago, people realized that magnets orient
themselves in north-south directions. They took advantage of
this to build compasses — devices that will always show the
direction, even at night or when the sky is overcast. Without a
compass, the great explorers such as Christopher Columbus
and James Cook would never have been able to cross the
world’s oceans, since they never would have been able to find

James Cook

Magnetism

Christopher Columbus

IN EVERYDAY LIFE…

…compasses are incredibly
important, even if you can’t
always see them.

You probably know that
magnetic compasses have
been guiding ships across
the oceans for hundreds of
years.

But there are also electrical
magnets — magnets, in oth­er words, that get their pow­er from electric current. You
can find them inside electric
motors and speakers, in bi­cycle dynamos and in the
gigantic electrical genera­tors in power plants.

As you can tell from these
examples, electricity and
magnetism are very closely
related.

You will be exploring both
domains in the exciting ex­periments in the next
section.

their way across the seemingly endless expanses of water.



Electromagnetism

Are electricity and magnetism related? Or are they completely dif­ferent natural phenomena? In the following experiments, you will
be exploring the strange connections between them, and you will
learn about some of their useful applications.



EXPERIMENT 51

Astonishing
electrical effect

Can electricity influence magnets? Find
out with the help of your hanging magnet
apparatus.

HERE’S HOW

Assemble your hanger device with base,
arm, cord, and the double bar magnet,
and let the magnet come to a resting
position.

Secure the alligator wire clip to one of the
battery case terminals, and then guide the
wire under the hanger base in such a way
that it runs parallel to the lengthwise
direction of the bar magnet. Place the
other alligator clip near the second bat­tery terminal.

Electromagnetism

CAUTION!

You should only tap the clip very briefly on
the battery terminal, one second at most. If
the current were to flower longer, the bat­tery and wire might get too hot, and the bat­tery would quickly get used up!

Tap this other clip briefly against the bat­tery terminal. The magnet will turn a lit­tle. After it has turned a little, it will ori­ent itself at right angles to the wire. Note
the side to which the red end moves.

Unfasten the clip, turn the battery case
around, and attach one of the clips again.
Tap briefly against the free battery termi­nal again. Now the current will be flow­ing in the opposite direction through the
wire. Does that have an effect on the
direction that the magnet turns?

WHAT’S HAPPENING

As you know, magnets will only react to other

magnetic fields. If your bar magnet reacts to

the reversed current by turning in the opposite

direction, that shows that the wire is produc-

ing a magnetic field as the current flows

through it — the wire is becoming a magnet.



EXPERIMENT 52

Intensified electrical effect

Do you think you might be able to intensify the effect on the bar mag­net by using more than one wire? Or maybe it will work to coil a sin­gle wire multiple times to form a spool.

HERE’S HOW

Wind the red plug wire around your finger to form a coil, and secure
the coil in place with some tape.

Connect the wire to one of the battery case prongs via an X-connec­tor. Connect the other end to an I-connector via an alligator clip.
Place one of the blue alligator wire’s clips on the other side of the
I-connector.

Hold the spool two to three centimeters away from the red end of the
bar magnet, and briefly touch the alligator clip at the free end of the
blue wire against the free battery terminal. The red end of the bar
magnet will turn toward or away from the spool.

Reverse the direction of current flow and repeat the experiment. In
what direction does the magnet turn now?

WHAT’S HAPPENING

The spool is acting like a bar magnet with a north and a south

pole. If you switch the direction of current, the poles will also

switch, and the magnet will turn in the exact opposite direc-

tion from before.

Of course, the spool is only magnetic while current is flow­ing through it. So it’s an electromagnet — unlike bar or ring

magnets, which retain their magnetic power permanently

and are therefore known as permanent magnets.



TIP!

Only let the current flow
very briefly (a few sec­onds), or the battery will
quickly get used up.

EXPERIMENT 53

Even stronger
electrical effect

A permanent magnet can make iron mag­netic. Can an electromagnet do that too?

HERE’S HOW

Use a nut to connect two screws together
(figure ).

Wind the red alligator wire onto the
screws to form a spool (which it would be
good to tape in place as in figure ).

Connect the alligator wire to the plug
wire as you did in the last experiment, and
the blue alligator wire to the battery.





Electromagnetism

Strength from electricity

Electromagnets have two other distinct
advantages over permanent magnets.
First: You can turn them on or off when­ever you like. Second: You can construct
them in such a way that they can handle
very strong electrical currents. These
currents can, in turn, produce magnetic
fields that are much more powerful than
anything a permanent magnet can
achieve.

Repeat the “intensified electrical effect”
experiment, but this time with the iron
piece inside the spool. What do you
notice?

WHAT’S HAPPENING

The spool’s power is noticeably

stronger, since the iron increases

the power of the electromagnet

quite a bit. It seems to concentrate

the power inside itself. So power-

ful electromagnets always have

an iron core.

TIP!

Only let the current flow
very briefly (a few sec­onds), or the battery will
quickly get used up.



EXPERIMENT 54

Electromagnets love iron too

The horseshoe-shaped electromagnet in the kit is even stronger than your
homemade electromagnet. But the construction is very similar: two
spools mounted on a U-shaped iron core. See how it works!

HERE’S HOW

Connect the horseshoe electromagnet to the battery via the push button
switch and two plug wires (figure ). Before turning it on, hold a few
pieces of iron (screws or a nut, for example) in front of the bare metal
prongs. You won’t feel any pull at all.

Now press briefly on the button to make current flow through the horse­shoe. The pieces of iron will be attracted to it.

What happens to the iron pieces sticking to the magnet when you switch
the current off?

Test the strength of the magnet. How close do the iron pieces have to get
for them to react? Are both poles equally strong?

Try carrying out the experiment using the colorful disks (figure ).





WHAT’S HAPPENING

The horseshoe electromagnet real-

ly does turn into a magnet — an

electromagnet — when current

flows through it. Then it attracts

iron just like a permanent magnet.

But it only does so while the cur-

rent is flowing. Turn it off, and the

electromagnet loses its power.



EXPERIMENT 55

Iron arches

If the horseshoe electromagnet really is
turning into a magnet, you should be able
to make its magnetic lines of force visible.
Try it!

Electromagnetism



The names of

HERE’S HOW

Connect the electromagnet to the battery
via the push button, two plug wires, and
five X-connectors (figure ).

Spread the iron powder out into a fairly
even layer on the floor of the box.

Switch on the electromagnet and hold the
box with the iron powder a few millime-
ters above it. Tap gently on the box sev-
eral times. What do you see?

WHAT’S HAPPENING

When the magnet is switched on —

and only then — you will see the

typical pattern, familiar from the

bar magnet, form at the poles. The

lines arching from one pole to the

other should show up particularly

clearly once you tap on the box a

few times (figure ).



the poles

You may be wondering
why the poles of a mag­net are called the north
and the south pole.
There are historical rea­sons for it:

In earlier times, people
were familiar with com­passes, but didn’t know
anything else about
magnetic forces.

People thought it was
Earth’s poles, or gigantic
magnetic mountains
near them, that were
attracting the compass’s
needle. The ends of the
compass needle that
were pointing in those
directions were thus
given matching names.



EXPERIMENT 57EXPERIMENT 56

Polarity tester Switching poles

Do you think an electromagnet also has a north and a south pole? You can’t tell
by touching it with the bar magnet, since the bar magnet will react to the iron
inside the electromagnet. But maybe you can use your sensitive hanging magnet
tester.

HERE’S HOW

Connect the electromagnet to
the battery via the push button,
two plug wires, and five
X-connectors.

Set it next to the hanger device
with one of its poles a few
centimeters away from the
bar magnet.

Switch on the electro­magnet for a few sec­onds. What happens?

Now push the other pole
closer to the bar magnet and
briefly switch on the current
again. What do you notice? Test
the needle again. What does it
show?

WHAT’S HAPPENING

The bar magnet reveals that when

the current is switched on, one of

the arms of the electromagnet be-

comes the north pole, while the

other becomes the south pole.



When you switched the connections to
the battery terminals, your homemade
electromagnet changed its poles. Do
you think that will happen with the
horseshoe electromagnet?

HERE’S HOW

Place the horseshoe electromagnet next to the hanger
device with its left pole considerably closer to the bar
magnet than the right pole.

Briefly switch on the current. Note the color of the bar
magnet pole that turns toward the horseshoe magnet
pole.

Now reverse the connections at the battery case and
switch on the current again. Which one of its poles does
the bar magnet now turn toward the horseshoe pole?

WHAT’S HAPPENING

In fact, reversing the current

really does reverse the elec-

tromagnet’s poles as well

— the north pole becomes

the south pole and

vice-versa.

EXPERIMENT 58

Electromagnet’s
penetrating force

The magnetic powers of your permanent
magnets were able to penetrate all kinds
of materials, with the exception of iron. Is
that true for the powers of the electro­magnet as well?

HERE’S HOW

Assemble your hanger device and the
horseshoe electromagnet, and place the
two a few centimeters apart. The distance
should be small enough to make the bar
magnet react noticeably when you switch
on the current.

Electromagnetism

Now try holding objects made from a
variety of materials — such as glass, por­celain, wood, paper, cardboard, textiles,
plastic, your hand, an aluminum pot, an
iron baking sheet — between the horse­shoe electromagnet and the bar magnet.

Which materials will the magnetic force
penetrate, and which materials block it?

WHAT’S HAPPENING

The electromagnet behaves exactly

like a permanent magnet: Its mag-

netic force penetrates all the ma-

terials except iron.



EXPERIMENT 59

Electromagnet

INSIDE AN
ELECTRIC MOTOR

Equal magnetic poles re­pel each other, while op­posite ones attract. That is
the basic principle behind
an electric motor.

An electric motor consists
of a rotor, electromagnets
mounted in such a way
that they can spin and
turn one of their poles out­ward, where they will face
the poles of fixed electro­magnets forming the other
part of the motor, called
the stator.

For the motor to run, some
of the rotor magnets’
poles have to be attracted
by the adjacent stator
poles and turn in their
direction.

At just the right moment,
by switching the flow of
current, the stator poles
are then repulsed by their
neighbors, keeping the ro­tor turning continuously.

Stator

Rotor

Stator

N

N

S

S

  

N

S

N

S

N

dance class

In Experiment  (Dancing magnets), you
were able to send the bar magnet into a
rapid spinning motion through skilful
manipulation of the ring magnet.

The same idea can work even better with
the electromagnet, since all you have to
do in this case is turn the current on or off
at just the right moment.

HERE’S HOW

Place the horseshoe electromagnet a few
centimeters in front of the bar magnet
and briefly switch on the current.

When the bar magnet turns, switch off the
current again, then switch it back on, and
so on.

Try to find the right switching rhythm to
match the rotation speed of the bar

N

S

S

WHAT’S HAPPENING

What you’ve built here is a very

primitive electric motor. It works

on the same principle as the small

motor in this kit, as well as the huge

engines that drive electric trains

and all-electric cars.

magnet.

With a little practice, you will be able to
send the bar magnet into a rapid spinning
motion just by switching the current on
and off.



EXPERIMENT 60

Electromagnetism

WHAT’S HAPPENING

Speaker

An electromagnet, with its magnetic force
able to be turned on or off at will, can be
used to make some very interesting appli­ances — a very simple speaker, for
example.

HERE’S HOW

Tape a sheet of paper over the lid of a
cardboard box. Tape an iron disk from the
small parts pouch to the center of the paper.

Connect one of the horseshoe electro­magnet’s prongs to one of the battery
terminals with one of the plug wires. Clamp
the red alligator wire to the magnet’s second
prong.

Place the horseshoe electromagnet on a
short stack of books, with one of its arms
just far enough away from the iron disk that
they will not touch when the current is
flowing. Secure it in the desired position with
a little tape.

As soon as the coin or the file slides

across the battery terminal, it rap-

idly closes and opens the electrical

contact — a lot faster than you

could do by hand. So the electro­magnet becomes magnetic and

non-magnetic in quick succession.

These oscillations are transferred

to the disk on the sheet of paper,

and from there into the air, which
you hear as sound — the coin

makes the paper crackle, and the

file makes it hum.

Permanent magnet

Wire spool

Attach the free clip of the alligator wire to a
coin with ribbed edges. Rub the coin several
times back and forth across the free battery
terminal. What do you hear?

Attach a file to the red alligator clip and
move it gently across the battery terminal.
What kind of noise comes from the paper?

SPEAKER

A speaker also contains a cardboard mem­brane and two magnets. Usually, a tiny spool
of wire will be attached to the cardboard
membrane, into which the oscillations of elec­trical current will be fed. In this way, the spool
is turned into an electromagnet. This spool is

surrounded by the magnetic field of a strong
permanent magnet. The fluctuations of mag­netic force mean that it is more or less strongly
attracted by this permanent magnet. It moves
in rhythm with the fluctuations in current, and
passes these movements on to the membrane.



EXPERIMENT 61

Remote
control

If an electromagnet can attract
iron, it can also open and close
an electrical contact. This kind
of arrangement is known as a
“relay.” Relays have many uses
in electrical engineering.

HERE’S HOW

Remove the metal prong fastener strip from a
folder, and use a piece of sandpaper to roughen
up its surface to about three centimeters from
both ends. Attach the fastener strip to the hang­er device by partly wrapping the strip around it
and then securing it with tape. Its end should be
about three centimeters above the table surface
when the hanger is standing upright.

Connect the horseshoe electromagnet to the
battery case via switch, plug wire, and X- and
L-connectors.

Assemble a second circuit with light, I-connec­tors, and both alligator wires. One of the alli­gator wires will lead from the light to one of
the bare poles of the horseshoe electromagnet.
Clamp one end of the other wire to the battery’s
second terminal and the other end to the metal
fastener strip, near where you attached it.

Arrange the horseshoe electromagnet and the
hanger in such a way that the magnetic poles
and the strip are at the same height. Place a
book under the horseshoe electromagnet if
necessary.



WHAT’S HAPPENING

The electromagnet attracts the met-

al strip to touch its pole. When that

happens, the electric circuit is

closed and the light shines. When

you break the circuit, the light

turns off and the strip springs back.

The magnet should only touch the metal strip
when it is switched on. When that happens, one
of the two bare arms of the horseshoe electro­magnet should touch a part of the metal strip
that you rubbed bare.

Now, when you send current through the elec­tromagnet, the bulb will light up. What do you
see when you switch the current off?

EXPERIMENT 62

Morse telegraph

Before the internet or telephone, people
sent messages by Morse code through
wires running between cities and conti­nents. After radio technology was invented
those message were sent wirelessly around
the world.

Would you like to build a Morse telegraph
to render dots and dashes audible? With a
little dexterity, you can certainly build this
kind of device. You already know the Morse
code symbols from page .

HERE’S HOW

Electromagnetism



TIP!

If you can get a few
meters of dual-cable wire
from an electronics or
hardware store, you may
be able to figure out how
to install this system
between two different
rooms in your house.

Assemble two circuits supplied with elec­tricity from the battery case. One, shown in
figure , will power the motor and contain
the two-way switch and two I-connectors.
The other will supply current to the horse­shoe electromagnet, and it will have a
push button so you can switch the current
on and off.

Again, attach the metal prong fastener
strip to the hanger device so that it can
swing freely, but without slipping, at a
height of about three centimeters (figure ).

Tape the horseshoe electromagnet to the
battery case so it’s at just the right height
(figure ).

Continued on the next page…







EXPERIMENT 62

 



HERE’S HOW IT CONTINUES

Attach a piece of tape to each of the bare sur­faces of the horseshoe electromagnet poles (fig­ure ). This will prevent the metal strip from
sticking to them after you switch off the current.

Now mount the hanger base on the cardboard
such that the metal strip swings a few millime­ters in front of the poles of the horseshoe elec­tromagnet, as shown in figure . Test to see if the
strip moves toward the magnet when you press
the push button, and that it swings back again
when you let go.

Secure the motor with its two I-connectors to the
cardboard near the end of the metal strip (figure
). Tape a narrow strip of paper to the end of the
metal strip, so that it just barely touches the yel­low propeller when attracted by the magnet.

Now switch on the motor and push the button in
Morse-code rhythm. What do you hear?



WHAT’S HAPPENING

The heart of this system is the electromagnet,

which attracts the metal strip when the current is

flowing. But because that would be hard to hear,

the paper contacts the rotating propeller to pro-

duce a humming sound. So you hear the dots

and dashes as short and long voice-like noises.

Of course, you shouldn’t operate this Morse

code system too long, since the motor would
soon use up the battery.

CHECK IT OUT

Electromagnetism

How is electricity produced
on a large scale?

A little history

Almost  years ago, the Danish physicist

Hans Christian Oersted discovered that

electrical current and magnetism are
closely related. His experiment with a
compass and a wire with current flowing
through it opened the way to countless
important practical applications.

In action

Electromagnets are found in electric
motors, in relays, in electrical gener­ators at power plants, and in power
network transformers. They are also
used in radios and televisions, record
players, microphones, telephones, and
speakers, in modern medical exam
machinery, as well as in the particle accelerators that physi­cists are using to explore the world of subatomic building
blocks. Without risk of exaggeration, you can truly say that
our world would be a very different place without
electromagnets.

If you wanted to use batteries to power subways, streetlights,
electric ovens, or the electric engines in factories, you wouldn’t
get very far. Fortunately, people discovered another way to pro­duce electricity over  years ago — by using an alternating
magnetic field to generate electricity in a spool.

That is what a bicycle dynamo uses, and on a much larger scale
it is also how large electrical generators work, by rapidly rotat­ing electromagnets past spools. The generators in power plants
are driven by turbines whose blades are in turn driven by falling
water (in hydroelectric plants) or by hot steam (in coal, oil, and
nuclear power plants). In wind power plants, the wind turbine
propeller drives the generator directly.



CHECK IT OUT

Notes on environmental protection

European wall outlet

How does electricity
get to your wall outlet?

Different kinds of power plants produce elec­tricity that feeds into your wall outlet through a gi­gantic network of wires, including those huge power
line towers you sometimes see in open areas. This net­work distributes the electricity over large areas of the
country and ultimately guides it to your house. More
wires lead from the house connection all the way to
each of the wall outlets.

Solar cells

A small portion of the electrici­ty produced today comes from

U.S. wall outlet

None of the electrical or electronic components in this
kit should be disposed of in the regular household
trash when you have finished using them. Instead,
they must be delivered to a collection location for the
recycling of electrical and electronic devices. The
symbol on the product, instructions for use, or pack­aging indicates this.

The materials are reusable in accordance with their
designation. By reusing or recycling used devices, you
are making an important contribution to the protec­tion of the environment.

Please consult your local authorities for the appropri­ate disposal location.

the blue or black solar cells
like the ones you may have
seen on roofs. They convert the
light of the sun directly into
electricity — as long as the
sun is shining, of course.



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Kosmos experiment kits are designed by
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While the majority of our products are
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regardless of origin, follow the same
rigid quality standards.

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