Electro Magnetism

An educational product by

Mexus Education Pvt. Ltd.Regd. OfficeNo. 135 / 2 / A, Muktanand MargCHALA, Vapi 396 191 (Gujarat) Mumbai Office612, Midas, Sahar Plaza Complex M V Road, J.B. Nagar, Andheri (E)Mumbai-400 059

For Customer CareContact: +91 922 322 4044 Email: [email protected]

For sales enquiry: [email protected]

learning manualMODELS

189 PIECES 6

Trains moving at a speed of about 470 Km/h, cranes lifting tones of weight to hundreds

of meters of height, all this would just have been a dream if British Electrician, William

Sturgeon wouldn't have taken an initiative for the invention of electromagnet. In the year 1825,

he came up with an electromagnet which was horse shoe shaped. It was after then, when

major changes in the field of science took place. Electromagnet has really proved to be a life

changing invention.

Electromagnetism is an interface between electricity and magnetism. It shows how magnetic

effect is created in a region of electric field and vice-versa. This kit aims at the same concept. It

will let you to get familiar with the concepts of electricity and magnetism individually and then

will introduce you the relation between the both. It will train you from the basics to the

advanced level. It will let you to make combination of batteries in series as well as in parallel

and hence will show you the difference between the two connections. You will be working with

LEDs and will also learn about Earth's magnetism. The activities included will teach you about

circuits, connection of equipments in series and parallel, and also make you familiar with the

working of motor (DC). The activities that are included in the package are as follows:

· Traffic Light

· Crocodile

· Morse code

· Electric Train

· Electromagnetic Crane

· Sea Gull Park

1

RecommendationsChildren can easily learn the concepts of electricity and magnetism in physics through this kit.

It helps children lay the foundation of electricity and develop logical thinking through every attempt inÊthe assembly.

1. Please read these instructions, follow the safety rules and keep them for reference.

We recommend that you make the models in the order that is given. You will then be able to

understand assembly of parts and soon many more different models you wish.

2. This is a toy that has been designed for children over 8 years of age. It is designed to help

children discover what an electric circuit is and what magnetism is, while creating variety of models.

3. Discuss the safety warnings and possible risks involved with the children before allowing

them to build these models.

4. Do not try to plug the wires or accessories into any electrical outlet. This would be

extremely dangerous. Designed for batteries only.

5. CLEANING:

* Before cleaning, take out the batteries.

* Only use a cloth that has been slightly dampened with water.

* Never use a detergent.

INTRODUCTIONCONTENTS

PARTS LIST

HOW TO ASSEMBLE

ELECTRICITY IN REAL LIFE

ABOUT ELECTRIC CURRENT AND THE RELATED EXPERIMENTS

ABOUT MAGNETISM AND THE RELATED EXPERIMENTS

ABOUT ELECTRICITY AND MAGNETISM

ABOUT MOTOR AND THE EXPERIMENTS

ASSEMBLY EXAMPLES

Model 1 Traffic Light

Model 2 Crocodile

Model 3 Morse Code

Model 4 Electric Train

Model 5 Electromagnetic Crane

Model 6 Sea Gull Park

P. 2

P. 3

P. 4-6

P. 7-15

P. 16-19

P. 20-21

P. 22-23

P. 24-36

P. 24-25

P. 26-27

P. 28-29

P. 30-31

P. 32-33

P. 34-36

Warning To ParentsThis toy is not suitable for children under 3 years of age. It contains small parts that a child could swallow.

This toy must be kept out of the reach of very young children.

Safety Guidelines1. The batteries must not be recharged.

2. Only re-chargeable batteries can be charged under the supervision of an adult.

3. Do not mix chargeable and non-chargeable batteries .

4. Only the recommended batteries are to be used.

5. The polarity of the batteries must always be observed.

6. The terminals of a battery must not be short-circuited.

7. The old batteries must be disposed of as hazardous waste.

8. Follow the recycling instructions given on the battery.

Warning 1. Remove the batteries when not planning to use the device for a long period of time.

2. Misuse of batteries can cause them to leak, which damages and corrodes the area around

the battery, creating the danger of fire, explosion and personal injury.

INTRODUCTION P. 1

32

PARTS NAMES

LONG FRAME-YELLOW

FRAME-GRAY

FRAME-BLUE

SQUARE FRAME-GRAY

LONG ROD-YELLOW

ROD-GRAY

ROD-YELLOW

3-HOLE ROD-YELLOW

5-HOLE ROD-GRAY

DUAL ROD-GRAY

BENDED ROD-GRAY

XL DR. AXLE

L DR. AXLE

M DR.AXLE

DRIVE AXLE-GRAY

BAR

DOUBLE-SIDED BASE GRID

L GEAR-YELLOW

M GEAR-YELLOW

S GEAR-RED

20T CHAIN GEAR-YELLOW

L PULLEY-GRAY

M PULLEY-GRAY

PCS

2

2

4

4

2

1

2

6

5

2

4

1

3

1

1

1

4

2

12

7

1

1

1

NONO.NO

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

PARTS NAMES

S PULLEY-GRAY

ROD CONNECTOR

EGG CAM

CRANK WITH FLANGE

AXLE

CAM CONNECTOR

BASE CONNECTOR

PEG

GEAR FIXING

PEG /AXLE REMOVER

WIRE CLIP-RED

WIRE CONNECTOR-RED

WIRE CLIP-BLACK

WIRE CONNECTOR-BLACK

SWITCH

CUBE CONNECTOR

BATTERY HOLDER

BULB HOLDER-GREEN

BULB HOLDER-RED

BULB HOLDER-YELLOW

POWER PACK WITH SPINDLE GEAR

ENGIGONEER-HEAD

ENGIGONEER-BODY

PCS

1

2

1

1

12

1

5

23

3

1

1

3

1

3

3

4

2

1

1

1

1

1

1

NO.

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

PARTS NAMES

ENGIGONEER-HAND

ENGIGONEER-FOOT

HINGE

BUTTON FIXER

TWO-IN-ONE CONVERTER

90 DEGREE CONVERTER L

TAKE-UP ROLLER

HOOK

BELT

STRING-50CM

WORM GEAR

PEG CONDUCTOR

IRON ROD

WINDING REEL

PLASTIC SHEATH WIRE-400CM

ROUND MAGNET

RECTANGLE MAGNET

COMPASS

IRON POWDER PACK

DIE-CUT CARD

PCS

2

2

3

9

4

8

1

1

1

1

1

3

1

1

1

4

1

1

1

1

NO.

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

TOTAL 189

Assembly 1

Assembly 2Connecting Base Grid, Frame And Rod

Connecting Wire Connector And Switch, Bulb Holder Or Motor

Pulling Peg Off

H I

"A"A"A""A

O

LM

N

Changing The Bulb

KJ

F

G1G1 G2G2OFF ON

Fixing Battery

While fixing the "AA" batteries, pay attention that the polarity (+ and -) on battery and battery holder should meet.

Connecting Battery Holders

AB C

WARNING!

1) When battery holders are snapped together as in Fig. A or

B , we call it "BATTERY IN SERIAL".

2) When battery holders are snapped together as in Fig. C ,

we call it "BATTERY IN PARALLEL".

The Following Connections Are Never To Be Made

Connecting Battery Holder, Wire Connector, Cube Connector And Switch

D E

NOT CONDUCT

Note!

Be sure to twist on the bulb tightly so that the electricity is conducted.

The sockets of Cube Connector can conduct electricity

except the one with the logo of GIGO so that it can be

connected to battery holder (as Fig. D shows) or switch (as

Fig. E shows) and used as electricity dispenser.

Use side "A" of Axle/Peg Remover

to pull off the Peg. (as Fig. O shows)

1) Squeeze the cap and pull it off the holder. (as Fig. J shows)

2) Twist off the worn-out bulb and twist on a good one. (as Fig. K shows)

3) Squeeze the cap and put it back to the holder again.

PARTS LIST HOW TO ASSEMBLE

54

Electricity has become indispensable in real life with the development of technology. Do you know how it

comes to our life? What features does it have? What can we expect it to do?

Electricity has always been with us on earth. About 2000 years ago, Greek found that amber would

attract dry leaves, feathers and small rag towards it after it was rubbed. They called amber “elektron” (It

sounds like electricity in English.) and this mysterious attractive power was then described as “electric”

in English-speaking countries. In the18th century, Benjamin Franklin discovered the existence of

electricity and led us to a continuous research into electricity. In 1785, Charles Augustin Coulomb

discovered the interactive relationship between two and brought us new knowledge

about “electricity”.

People thought electricity and magnetism were two irrelevant features in physics until 1802, when Hans

Christian Oersted found out the effects between electric current and magnetism. That is, a magnetic field

will be formed around a current-carrying wire. This magnetic field is the same as that formed by a simple

magnet. Both of them can make the compass needle deflect. This proves that electricity and magnetism

are related to each other and both exist at the same time.

From then on, scientists had been exploring electricity and magnetism for several decades.

Andre Marie Ampere, 1775-1836, devoted himself to the measurement of electricity as a pioneer. The

international unit of electric current, A (Ampere), comes after his name. Carl F. Gauss, 1777-1855,

valued the strength of electric field. George S. Ohm, 1784-1854, discovered voltage and resistance.

Michael Faraday, 1791-1867, used iron filings to show magnetic lines of force on the magnetic field

formed around the magnet. This was a breakthrough in the traditional knowledge then.

The development of electricity has been going on with many scientists’ endeavor until James Cherk

Maxwell , 1831-1879, integrated the theories of “Gauss”, “Ampere”, and “Faraday” to achieve a common

theory of magnetic field.

Electricity is a kind of energy, a source of power. It exists in the nature of the earth, such as lightning.

1) The development of electricity

electric charges

Fig. Lightening in the sky and the North Pole and the South Pole are

the electricity and magnetism in the Nature.

2) Electricity in real life

There are lots of electrical appliances in our life. They all need electricity to make them work. Where does

electricity come from? Let’s study in the following paragraphs.!

Firstly, we need to know the relationship between electricity and magnetism.

1) Faraday discovered that a coil would get charged with electrified interaction caused by the

change of magnetic field when a magnet is added.

2) The phenomenon that electricity is produced from the change of magnetic field caused by the

movement of magnet is called electromagnetic interaction.

3) The produced electricity is called interacted electricity.

4) The faster the magnet moves to and fro, the faster the magnetic field changes in coil , and

thus the greater the electric current is interacted..

5) The electricity can still be produced by moving the coil towards or away from the magnet

instead.

6) Based on this principle, we can continuously move mechanical device with external force to

change the position of magnetic field or coil so that continuous electric current is created.

Fig. 2 The relationship between magnetism and electricity

Insert the magnet rod Magnet rod stays unmoved Withdraw the magnet rod

Disconnected from earth

Electrostatic induction

C

Connected to earthBA

Remove the charged objectD

S

N S

N

S

N

Fig. 1 The method to charge the conductor by using the principle of electrostatic

induction is called the “electrified interaction”.

a) Insert the magnet rod, the

coil is charged

b) Hold the magnet rod still, no

electric current is produced

in the coil

c) Withdraw the magnet rod, the

coil gets the electricity flowing

in the contrary direction

S

N

N

S

S

N

ELECTRICITY IN REAL LIFE ELECTRICITY IN REAL LIFE

76

In general, generators produce very high-voltage electricity so that it can be transmitted through a

long distance to our houses. But such electricity cannot be used. Normally the electricity

company will build a transformer station close to residential district to adjust the voltage to an

appropriate level before it is distributed to houses.

Power station transforms different kinds of energy into electricity to provide households

demands. The power distributed to our houses is called AC (alternating current), that is, the

electric current that changes it’s direction and amount at regular intervals with time, while dry

batteries or rechargeable batteries are DC (direct current), that is, the electric current won’t

change with time.

Fig. Distribute the electricity to our houses

Thermal power plant

Hydraulic power plantNuclear power plant

Wind power plant

Transformer

station

High-voltage

electricity tower

Deliver-transform system Electricity distribution system

Step-down

substation

Transformer

on pole

Houses

Electric pressure:

a) The electric potential difference between the positive pole and the negative is called the

electric pressure.

b) The unit of electric pressure is voltage (V)

c) The general voltage of a battery is 1.5V, that is, the electric potential of the positive pole is

1.5V higher than that of the negative.

Fig. 1 Comparison between direct current and alternating current

Fig. 2 Structure of the battery

3) The bulb is shining!What kind of toys do you have at home? Do they shine at night, make sounds or move? What

are they made of? What makes them shine or move? Do they all use batteries?

1) dry batteries

a) consist of 2 poles, positive (Symbol: + ) and negative (Symbol: - )

b) supply DC electricity transformed from chemical energy.

c) positive pole has higher electric potential than negative

d) the protruding end of the battery is the positive pole, while the other end is negative.

BAA B

Ele

ctric

curre

nt

Ele

ctric

curre

nt

Time

Direct current (DC)The amount and direction of

the current are fixed

BA

Alternating current (AC)

A B

AB

Ele

ctric

curre

nt

Ele

ctric

curre

nt

Time

The amount and direction

of the current are flexible

Positive pole Symbol: +Carbon rod (positive)

Zinc (negative)

Ammonium chlorideManganese dioxideAmylum compound

Negative pole Symbol: -

ELECTRICITY IN REAL LIFE ELECTRIC CURRENT AND THE RELATED EXPERIMENTS

98

ELECTRIC CURRENT AND THE RELATED EXPERIMENTS ELECTRIC CURRENT AND THE RELATED EXPERIMENTS

2) Battery Holder

When we use battery at home, the positive and negative pole need to be connected to work.

We usually put it in a battery holder so that a wire connector can easily connect them. Be

sure to insert the battery in a correct direction.

Fig. 1 Electric potential difference produces voltage and current.

Fig. 2 Insert the battery in a correct direction

1.5V

Water at higher

location

Water at lower location

Our bulb holder contains 2 copper plates which lead two poles of the bulb separately to itÕs two

holes where the copper plates come through so that they can be conducted through the wire

connectors which are inserted into the holes. This plug-in design is very convenient for us to

build a circuit.

Fig.Ê1 Wire connector, no matter it is red or black, can conduct electricity from one end to the other.Ê

Fig. 2 Tungsten filament can change the energy released by electric current into light and heat.

Tungsten double spiral filament

Power wires

Filament

3) Wire connector

Wire connector it with helps to conduct electricity. It is made of copper, a metal, wrapped with

plastic cover to protect them from being touched each other or by people to cause short

circuit or electric shock.

4) Bulb Holder

Bulb can produce light for people when it is dark. It produces light by heating up the filament.

But how does it work? When electric current flows through the filament it releases energy and

thus produces heat . In 1879, Edison used coal as the material for the which in turn heats the filament

filament. Although coal has a very high melting point ( ) it's easy to be consumed and 3550¢J

last only a short time and needs to be insulated from air (otherwise it will burn in the air).

We are using tungsten filament with melting point at . It has longer life but still burn in 3410¢J

the air. Therefore the light bulb needs to be a vacuum. If you find your light bulb does not

work, check if the filament is broken first. The bulb can be easily changed if needed.

Electric current:

a) Electric current is the flow of electric charge flowing in the conductor

b) With the potential difference, plus a conducting wire from positive to negative, the electric

current happens.

c) The direction where electricity flows is from high to low potential

d) The strength of the electric current depends on it’s amount. It is measured by Ampere (A).

The speed of the electric current is the same as that of light, About 3 x meter/second.10 8

1110

1) Dry battery provides electric current and voltage which a circuit needs.

We call it power source.

2) Light bulb is the electrical device in a circuit

3) The power source and the electrical device are connected with wire connectors.

4) Connect the battery holder, bulb holder with red and black wire connectors.

5) Does the bulb shine?

6) Use your hand to touch the bulb to see if the temperature is increased.

Attention: Don’t touch the light bulb used at home to avoid a burn.

Because the high voltage it uses, it may become very hot!

Fig. 1 The bulb is shining

1.5V

+

-battery battery

1.5V

+

-battery

switch

bulb

Fig. 2 Circuit

Fig. a When switch is turned off, the circuit is disconnected.

Fig. b When switch is turned on, the circuit is connected.


1) Let the bulb shine

a) Bulb is shining

Let’s build a basic circuit including battery holder, bulb holder and wire connectors.

2) Use the switch to turn on or off the bulb.

Connect the battery holder, switch and bulb holder with wire connectors.

1) When the switch is turned on, it allows the current to go through. In this case, the switch

is said to be in a closed position.

2) When the switch is turned off, it doesn’t allow the current to go through. In this case, the

switch is said to be in an open position.

3) The circuit is shown below:

Chapter 1: Experiments on conductors

Try to see if the following objects can conduct

electricity when they are put on the position of

the question mark on Fig. 1.

Please tick the boxes with the right answers

behind them.

Spoon

¡¼Can

¡¼Can not

Coin

¡¼Can

¡¼Can not

Pencil

¡¼Can

¡¼Can not

Key

¡¼Can

¡¼Can not

Cube connector

¡¼Can

¡¼Can not

Belt

¡¼Can

¡¼Can not

Getting to know conductors and insulators:

Objects that allow electricity to go through are called conductors; objects that does not allow

electricity to go through are called insulators. The reason that conductors can conduct is

because they contain negative free electrons which flow around under the effect of battery to

cause electric current, whereas insulators do not contain any free electrons and thus they

cannot allow electricity to go through.

1312

Chapter 2: Batteries in Series and Batteries in Parallel

There are copper plates coming through on all sides of the battery holder ends except the

bottom. When two battery holders are connected together the batteries are connected through

these copper plates, too.

1. How to make Batteries in series

So the higher the voltage received from the batteries is, the brighter the light bulb will be.

Chapter 3: Bulbs in series and Bulbs in parallel

A bulb is structured by putting a tungsten filament in a vacuum glass cover where the electricity

flows through to burn filament to release light and heat. There is no distinction between the

poles of bulb. The bulb can be lighted only if the current goes through two poles of it. The bulb

can be connected in serial or in parallel, too.

Batteries in series is to link batteries together in a line with positive and negative poles

connecting each other. The more batteries, the greater voltage there is in the circuit. For

example, the voltage for one battery is 1.5V, two batteries in series will have 3V, 3 batteries in

series will have 4.5V, and so on. However, the amount of the current stays the same no matter

how many batteries are in series in the circuit.

2. How to make Batteries in parallel

Batteries in parallel is to link batteries together side by side with same polarity ends

connecting each other. In this case, the voltage remains the same. However the total amount of

electric current become greater and thus the batteries in parallel can last longer.

Attention: Batteries need to be removed from battery holders when they are in series or

in parallel to avoid electricity being consumed when they are not to be used.


1.5V

1.5V+1.5V=3V

+

-

+

-

1.5V

+

-

battery

battery

1.5V 1.5V

+

-

+

-

1.5V

I I+I

I

+

-

battery battery

I

Which bulb is brighter in the following circuits? Please tick the box before the right answer.

¡¼Batteries in series ¡¼Batteries in parallel

When bulbs are in series, the input voltage will be

shared among the batteries. For example, if the input

voltage is 3V for 2 bulbs in series, each bulb can

share 1.5V.

If the input voltage is 3V for 3 bulbs in series, each

bulb can share 1V only.

Therefore the brightness of bulb will come down with

the bulbs increased in a series.

When bulbs are in parallel, the input voltage won’t be

shared among the bulbs.

And thus, the brightness of the bulbs would stay the

same even the bulbs are increased

in a parallel.

1) Bulbs in series

Fig. 1

Bulbs in series is very similar to batteries in series.

They are connected together in a line in the circuit.

2) Bulbs in parallel

Fig. 2

Bulb in parallel is very similar to batteries in

parallel. They are connected together side by side

in the circuit.

1514

3) Experiments on bulbs in series and bulbs in parallel

Try to see which bulbs in the following connections are shining brighter and tick the box

with the right answer after it.

The input voltage is 3V. If the bulbs are in series, each bulb can share 1.5V only. If bulbs are in

parallel, each bulb can get all 3V. The greater the voltage shared by each bulb is, the brighter

the bulbs will become. Could you see this principle from the experiments you made?

Chapter 4: Experiments on series and parallel

Experiment 1:

Is there any difference in the brightness of the bulbs between the following two connecting

ways?

And what about difference in the circuits?

Experiment 2:

When the switch is turned on and off, is there any change happening to the brightness of the

green bulb? Why?

¡¼Bulbs in series ¡¼Bulbs in parallel

Experiment 3:

Compare the following two connections to see if the brightness of the bulbs are the same?

Why?

Experiment 4:

When the circuit is completed, please turn on and off the switch to see if the green bulb and

the yellow bulb make any change?

1.5V

+

-

1.5V

+

-

switch on switch off

switch off

green bulb

green bulb

switch on


1716

ABOUT MAGNETISM AND THE RELATED EXPERIMENTS ABOUT MAGNETISM AND THE RELATED EXPERIMENTS

Magnetism is everywhere in real life, such as the magnet on the message board, the lock of a

pencil case, a motor's rotation or a crane in recycling field. Even the earth itself is also a big

magnet. That's why we can use compass to guide direction.

A magnet must have north pole and south pole. They always come in a party and can not be

alone. That is, nothing with one polarity can exist. Even if a magnet breaks into halves, the new

north pole or south pole will be developed from the broken part.

When two magnets come close to each other, the phenomenon of attraction or repellence will

happen. That is, when the north pole of Magnet A comes close to the south pole of

Magnet B, they will attract each other and connect together. On the other hand, if the north pole

of Magnet A comes close to the north pole of Magnet B, they will repel each other and be away

from each other.

S

NS

S

N

N

S

S

S

S

N

N

N

N

SN

SS

N

N

S

S

S

N

N

S

N

S

N

Different poles attract each other. Same poles repel each other. Same poles repel each other.

1) Magnet and compassThe compass needle is actually a magnet. The needle head is north pole and the needle end,

south pole. So when we take a magnet close to the compass, it is visible that the compass

needle will deflect. The is the principle of "Opposite poles attract, like poles repel."

The Earth itself is a magnet. We call it terrestrial magnetism. It maintains a very good

relationship between the rotation of the earth, the sun and the moon and enables us to stand

steadily on the ground, unlike astronauts in space station floating in the air. The Arctic of the

earth is actually the south pole of the terrestrial magnetic pole and the Antarctic of the earth is

the north pole of the terrestrial magnetic pole.

Since the needle head of the compass is the north pole of the magnet, it is attracted by the

south pole of the

terrestrial magnetic pole, the north pole of the earth. This makes the needle of the compass

always point to the north of the earth and makes compass a good tool for guiding the direction.

SN

S

S

N

S

N

N

S

N

N

S

S

N

1918

S N S N

Experiment 1: Car racing with the principle of magnet’s attraction and repellence

Make a comparison. Which car runs faster?

2) Magnetic lines of forceMagnetism of the magnet does not need any medium to expand its area. Objects within its

magnetic field will be affected. We call this unseen force ‘magnetic lines of force’. Magnetic

lines of force has its direction. It goes from the north pole outward to the south pole and from

the south pole inward to the north pole. It forms smooth curve closed lines which never meet

one another. The magnetic lines of force are the densest at two poles and the magnetic force

is the strongest in these areas. That means the strength of the magnetic force depends on

how dense the magnetic lines of force are.

Experiment 2: The observation of magnetic lines of force

Use iron powder pack to show the magnetic lines of force around a magnet and answer the

following questions.

1) Are the magnetic lines of force at two poles denser than those in other areas?

2) Are the magnetic lines of force getting thinner when they are farther from two poles?

3) Does the distribution of the magnetic lines of force maintain when the magnet moves?

Do you think the magnetic lines of force is three-dimensional?

3) MagnetizationMagnet can magnetize a paper clip or a nail. So the nail attracted to the magnet can attract

another nail and more. We call this phenomenon

magnetization. This phenomenon is only temporary. Once the magnet is moved away from

the metals the magnetism will disappear.

The magnets that we usually use are the permanent magnet, of which the magnetism will

always exist. However, if the temperature of the magnet increases

the magnetism will decreases.

Experiment 3: Magnet and paper clips

Make a comparison to see whose magnet can attract the most paper clips

Attract the paper clips one by one to see

whose magnet can attract the most.

The needle head (North Pole) of a compass would point the same direction as the magnetic

lines of force go. That is, the direction of the needle will be parallel to the magnetic lines of

force.

Place the magnet under the iron powder

pack and knock it couple times to see

magnetic lines of force.

ABOUT MAGNETISM AND THE RELATED EXPERIMENTS ABOUT MAGNETISM AND THE RELATED EXPERIMENTS

2120

ELECTRICITY & MAGNETISM ELECTRICITY & MAGNETISM

In the early days, people believed there was no relationship between electricity and

magnetism. But in 1820, a Danish scientist Orsted discovered that

when copper wires were connected with electricity, one end with postive, the other end with

negative to create a current flow therein ,

and moved close to the compass, the needle of the compass would be deflected. This proves

that a magnetic field will be produced around the current-carrying wires. This magnetic field

has the same feature as that produced by a magnet.

1) Magnetic effect of electric currentAny current-carrying wire can produce a magnetic field around it. This phenomenon is

called magnetic effect of electric current.

In the early 18th century, a French scientist Ampere made a deeper investigation on

magnetic fields and magnetic lines of force. He discovered

the magnetic lines of force of the magnetic field produced by the current-carrying wire was in

closed concentric circles,

and the direction of the circulation was perpendicular to the current-carrying wire.

According to the phenomenon Ampere discovered, the Empere's right hand rule can be

used:

1) To give the direction relationship between the current-carrying wire and the produced

magnetic field.

2) If the thumb of the right-hand points along the direction of the current, then the other four

fingers of the right hand circulate in the same sense as the magnetic lines of force.Ê

2) ElectromagnetIf we wind up a conducting wire and allow current to flow through, the produced magnetic

field is stronger than that from a straight wire. The more circles

we wind the wire the stronger the magnetic field becomes. Using Empere's right hand rule we

can then judge the features of the magnetic field.

The way is -

a) Circulate the four fingers along with the direction of the current on the wound up wire

as Fig. 1 shows.

b) Then the thumb is pointing to the north pole of the magnetic field, and the other end is the

south pole.

c) The N and S poles then form an electromagnet. However, if there is no current flowing

through the wound up wire is only a regular wire, without any magnetism.

When an iron bar is placed inside this current-carrying wound up wire, the produced

magnetism will come to this iron bar. Then the iron bar can attract metal. The iron bar

becomes a magnet in this way and so it is called an electromagnet. We can know the

polarity of the electromagnet with the right hand rule described above.

The strength of the electromagnet is defined by the strength of the current or the amount of

the conducting wire loops. Moreover, the direction of the electromagnetic field can also be

altered by the direction of the electric current. The most common appliances of

electromagnets are telephone receiver and speaker. It can also be seen on the arm of the

crane to attract metal in a large recycle factory or a construction site.

3) Overall, the thumb points to the direction of the current of current-carry wire, and the

fingers circulate in the same direction as the magnetic lines of force.

If a compass is placed in the circular magnetic field, the north pole of the compass will

move along the direction of the magnetic lines of force and point to the direction of the

section line against the magnetic field.

Resistance

Table top

Switch

Standing support

Batte

ry u

nit

S

S

S

S

NN

N

N

S

S

S

S

NN

N

N

Fig. 1

and moved close to the compass, the needle of the compass would be deflected.

2322

ABOUT MOTOR AND THE EXPERIMENTS ABOUT MOTOR AND THE EXPERIMENTS

Rotation of the motorThe concept of motor’s rotation is to change electric energy into

magnetic energy and then into kinetic energy to activate the

motor. The motor rotates to drive gears and create many movable

toys.

1) Structure of motor

a) A motor is made of loops of wires with 2 separate ends

connecting to the power source.

There are normally millions of loops in the motor.

But, for the convenience of explanation we use only one

loop .

b) The current comes from the positive end of the power

source and flows through the electric brushes and electric

loops to the negative end of the power source (battery).

c) There is only a slight contact between two electric brushes

and commutator

2) The concept of motor’s rotation

a) Magnetic force is produced when the current flows through

the wire loops. This force interacts with the North Pole and

the South Pole of the magnet to make the left side of the

loops goes up and right side of the loops goes down. The

magnetic forces from both side makes the loops rotate.

b) When the loops turn 90 , electric brushes degrees

disconnected from commulator, no current can flow through

and thus no magnetic forces are produced, but due to the

inertia of the rotation, it ll still rotate clockwise.

c) After the loops turn over 180 degrees, electric brushes

connected with commulator again, the current continues to

flow through but in different direction so that the loops still

rotate clockwise.

Experiment 2: Voltage and motor’s rotating speed

Compare with Experiment 1, which motor rotates faster? Why?

Building electric circuits Build the actual electric circuits according to the following circuit diagrams and observe their

operation.

Experiment 1: direction of the current and direction of the motor’s rotation

d) The function of the electric brushes and commulator is to change the direction of the

current whenever the loops turn 180 . This makes the loops rotate continuously.degrees

e) Therefore, when the polarity of power source changes, the direction of the current

changes and so does the direction of rotation.

SN

F

BI

SN

SN

F

B

I

wire loops

electric brushes

batterycommutator

Direction of motor’s rotation

¡¼clockwise ¡¼counter-clockwise

Direction of motor’s rotation

¡¼clockwise ¡¼counter-clockwise

1.5V

+

-

1.5V

+

-

1.5V

+

-

1.5V

+

-

switch switch

cube connector

cube connector

bulb(red)

bulb(yellow)

battery

motor

battery

Experiment 1 Experiment 2

1.5V

+

-

1.5V

+

-

switch

cube connector

cube connector

battery

battery

bulb(green)bulb(red)

motor

switch

battery

battery

motor

ASSEMBLY EXAMPLES ASSEMBLY EXAMPLES

2524

Model 1 T raffic Light ---

1.5V

+

-

1.5V

+

-

PARTS NEEDED

17

39

49 5850

4041 42 43 45

46

1 2 3

4 5

6 7 8

47 48

31

30 35 37

38

58 9

10 11

x1

x1 x1

x1

x1x1

x1 x1

x1

x2

x2

x2

x6

x2

x2 x2

x3

x3x3

x3x3x2

x2

9 10 11

12

Completed

1413

15


26

Model 2 Crocodile ---

PARTS NEEDED

1.5V

+

-

1.5V

+

-

1

17

49 575850 51 52 55

40

44

20

22 31

32

26

2830

35 37 38

3 4 56 7

9

11

12 13

x1x1

x1x1

x1

x1

x1x1

x1x1 x1

x8

x9

x1

x5

x5

x2

x7x10

x3

x3x2

x2

x2

x2

x4x4

x4

x4

x8

27

Completed

1 2 3

4 5

6 7 8

9 10

11 12

13

14


28

Model 3 Morse code ---

PARTS NEEDED

1.5V

+

-

1.5V

+

-

17

39

50

4041

42

31

30 34 35

36 37

2

x2

x5

x4

x4

x2

x2

x3

x1

x1

x1

x1

x2

x8

1 2 3

4 5

10

6 7

8 9

29

Completed

What do all those dots and dashes mean? The invention of the telegraph was followed by the invention of the Morse code. Referred to in the Navy as the dot-dash system, each letter and number is represented by a particular arrangement of dots and dashes. Morse code is usable in sound signaling (radio, sound and whistle) and visual signaling (lights and flags).

Want to really have some fun? Try out this Morse code translator.


30

Model 4 Electric T rain ---

PARTS NEEDED

x2 x2

x1

x1x1

x1

x1x1

x1x1

x1

x2

x2

x12x12 x23

x1

x1

x1

x2

x6

x2 x2

x4

x4

x41.5V

+

-

1.5V

+

-

57 58 62

5540 44 49

18 1920

2231 32

28

35 3738

23 4

7

8 9

10

14

13

1 2 3 4

6

7

8 9 10 11

12 13

1415

16

31

Completed

N

NN

5N


32

Model 5 Electromagnetic Crane ---

PARTS NEEDED

1.5V

+

-

1.5V

+

-

1 17

57 59 60 61

50 53 54

56

40 47

2021

31

32

2425

27 28

30

34 35 36 38

45 7

8

15

1613

x1

x1

x1x1

x9x1

x1x1x1

x1x1

x1

x1x1

x1x1x1x1x1

x1x3x2

x2

x2 x2

x2

x2

x2x2

x2x2

x2

1 23

4 5 6

7 8

910

11 12

13

plastic sheath wire

cotton stringScratch the paint off the reserved

plastic sheath wire to make it

conductive before it is clipped.

plastic sheath wire

cotton string 50cm

Wind up 100 times.

Reserve 15cm

long at both ends.

Push the gear to fix with the axle and make it not rotatable.

33

Completed

See if it can attract paper-clips.

Crank to make the mechanical arm rise and down.

Pull out the gear to be away from the axle and make it rotatable.


3534

Model 6 Sea Gull Park ---

PARTS NEEDED

1 2 3

4 5

7 8

17

39

57 58

50

55

40 4344

19

20

23

31

3225

29

30

35 3738

23

45

6 8 9

10

12 13

x1 x1

x1

x1

x1

x1

x1x1

x1x1

x4

x14

x2x5

x5

x2x4

x2 x2

x2

x2

x2x2

x2

x2

x2x2

x2x2

x2

6

9 10 11

12 13

14 15

ASSEMBLY EXAMPLES QUIZ

1.

2.

3. as

4.

5.

6.

Static electricity occurs when:

a. two metals are connected to a battery

b. different insulators are rubbed together

c. the weather is very humid

Two particles with the same charge

a. will repel from each other

b. will attract each other

c. None of the above

Materials that allow electricity to flow through them easily such as copper are called

a. Semiconductors

b. Insulators

c. Conductors

d. Inverter

Which among this is a not form of energy?

a. Heat

b. Electricity

c. Solar

d. Water

What is the advantage of using renewable energy?

a. They are eco-friendly

b. They don't produce harmful gas

c. We won't run out of them

d. All of the above

the force with which an electromagnet attracts a magnetic material towards itself

depends upon

a. the strength of current flowing.

b. The length of the conductor

c. The shape of the coil

d. All of the above

36

Pay attention to the arrow refers to the axle not interfere the rod.

Completed

37

11.

12.

13.

14.

Maglev trains work on the principle of:

a. Ohm's law

b. Electromagnetism

c. Hall effect

d. Newton's law

“The EMF produced around a closed path is proportional to the rate of change of

magnetic flux through any surface bounded by that path”. This statement is known as:

a. Fleming's law

b. Faraday's law

c. Hall's law

d. Lenz's law

When a current is induced in a body due to change in magnetic flux, that current:

a. Supports the cause of its production

b. Oppose the cause of its production

c. Flows in the direction of the magnetic field

d. None of the above

Two kinds of forces are associated with electricity; they are electric and magnetic

force. The connection between these forces was been demonstrated by:

a. Nikola Tesla

b. Joule

c. James Clark Maxwell

d. Michael Faraday

7.

8.

9.

10.

Two equal charges of opposite polarity separated by a distance compose a

a. Couple

b. Dipole

c. Electromagnet

d. None of the above

When a current carrying conductor is placed in a magnetic field, it experiences a force

which is given by:

a. Fleming's right hand rule

b. Ohm's law

c. Fleming's left hand rule

d. Boyle's law

The appearance of a voltage across a current carrying conductor when it is placed in

a magnetic field is known as:

a. Hall's effect

b. Magnetic effect

c. Ohm's effect

d. Faraday's law

Fleming's right hand rule:

a. Provides the direction of magnetic field when direction of flowing current and applied

force are known

b. Provides the direction of current when direction of magnetic field and direction of force

are known

c. Provides the direction of force when direction of magnetic field and the direction of

current are known.

d. Provides the polarity of appearance of voltage in a current carrying conductor placed

in magnetic field.

QUIZ QUIZ

3938

http://en.wikipedia.org/wiki/Electromagnetism

http://www.howmagnetswork.com/Electromagnetism.html

http://www.howstuffworks.com/electromagnet.htm

http://www.school-for-champions.com/science/electromagnetism.htm

http://www.youtube.com/watch?v=HQdLFEiVeCA

REFERENCES

40 41

Documents

Electro Magnetism