Unit 3: Electricity and Magnetism

Unit 3: Electricity and magnetism

3.3 Electricity

What would your life be like if there was no electricity?

1Use the word bank to complete the sentences below about electricity. Some have more than one correct answer.

aThroughout your house, you will probably find ______where you can plug in different electrical appliances.

bDuring a thunderstorm, huge bolts of electricity called ______shoot down from the sky.

cPortable electrical devices use ______
to provide their electricity.

dElectric motors turn electricity into ______.

eLight bulbs and fluorescent bulbs turn electricity into ______.

fTelephones turn electricity into ______.

gTelevisions turn electricity into ______.

hSpeakers turn electricity into ______.

iToasters and hair dryers turn electricity into ______.

jRadios turn electricity into ______.

kX-ray machines turn electricity into ______.

lElectricity is the flow of tiny particles called ______.

mElectrons are ______charged particles.

nElectrons flow around a ______.

3.4 Circuits

Below is a diagram of a simple electric circuit.

1Write these labels onto the diagram:

• switch

• light bulb

• battery

• positive terminal

• negative terminal

2Will this light bulb be lit up? Why?

______

3Draw a line at the switch to close the circuit – that is, to turn it on.

4Electrons flow in a current from the negative terminal to the positive terminal. Draw arrows on the diagram to show the direction of flow of electric current.

5Use the symbols below to draw your own labelled electric circuit.

3.5 Conductors and insulators

Remember - electricity needs a conductor in order to move.

Conductors allow electricity to flow through them,
while insulators resist the flow of electricity.

In many substances, the electrons are tightly bound
to the atoms. Wood, glass, plastic, ceramic, air and cotton are examples of substances in which electrons stick with their atoms. Because the electrons don’t normally move in these substances, they cannot conduct electricity very well, if at all. Therefore, these materials are electrical insulators.

Most metals have electrons that can detach from their atoms and move around. These are called free electrons. Gold, silver, copper, aluminium and iron have free electrons. These free electrons make it easy for electricity to flow through these materials, so they are known as electrical conductors.

1Use the information above to complete the topic map about
conductors and insulators of electricity.