iStarSign inScience 4 · Unit 6: Electricity · Cambridge Primary Science Stage 4
6.3 Using conductors and insulators in electrical appliances
15 questions · e.g. Why are handles made of plastic?
Questions
1. A kettle, a hairdryer and an electric mixer use which strength of electricity?
Check2. What material is used for the part of a hairdryer you hold?
Check3. Is the plastic on a hairdryer handle a conductor or an insulator?
Check4. Why does a plastic handle make an appliance safe to use?
- It stops electricity flowing into your hand.
- It conducts electricity away from you.
- It makes the appliance lighter.
- It makes the appliance work faster.
5. Where are the electrical conductors in these appliances?
- in the plastic handle
- in the metal wires inside the cable and the plug pins
- on the outside of the case
- in the plastic cover of the cable
6. Why is the cable of an appliance covered in plastic?
- The plastic insulates the metal wires, so you don't get a shock.
- Plastic is used only for colour.
- Plastic makes the cable conduct better.
- Plastic makes the electricity flow faster.
7. A kettle cable near the sink has worn insulation. Why is this dangerous?
- The bare metal conducts, and water nearby could give someone an electric shock.
- The kettle will boil too slowly.
- The plastic will melt the water.
- The kettle will stop working at once.
8. Why is it dangerous to touch a plug or switch with wet hands?
- Water is an insulator.
- Water with salts in it conducts, so electricity could flow into you.
- Your hands would get too cold.
- The plug would get rusty.
9. The pylons that hold up electricity cables are made of ...
Check10. Why must the cables on a pylon be kept apart?
- so the wind can cool them
- so electricity does not pass from one cable to another
- so the cables look tidy
- so birds can fly between them
- Check
12. Why are the cables on pylons made of metal?
- Metal conducts electricity.
- Metal keeps the cables cool.
- Metal is cheap and soft.
- Metal is an insulator.
13. What metal do you think the cables are made from?
Check14. Why are the separators on pylons made of ceramic?
- Ceramic is an insulator, so it keeps the electricity in the cables.
- Ceramic is a good conductor.
- Ceramic is very heavy.
- Ceramic makes the cables brighter.
- No, the cables carry very strong electricity that could kill them.
- Yes, if they wear rubber gloves.
- Yes, the pylon is made of metal so it is easy to climb.
- Yes, if it is not raining.