Lesson 5 Page 2
Discover: Testing For Conductors
Conductors and insulators are both useful in electric devices.
Have you ever looked closely at a power pole or high voltage power line? The wires are not directly attached to the power pole. The wires are attached to the poles with strange-looking glass or ceramic things. Why would the power company go to the extra effort to hang the power lines from these strange glass things?
Those glass "things" are very important. Connecting the wire that carries electricity directly to a power pole is not wise. That would mean electricity could travel down the pole, and if someone touched the pole, he or she could get shocked or worse. For that reason, glass or ceramic insulators are used to keep the power line from touching anything that is a conductor.
When we design and use electric devices, it is very important to know which substances are good conductors and which are good insulators. In this activity, you will test common substances to see if they conduct electricity.
How well do various substances conduct electricity?
- Electricity Kit Items: lamp holder and lamp, battery holder, 3 connecting wires
- 1.5 v battery (2 AA or 1 D cell)
- Common items you find around the home, such as – paper clip, metal foil, small rubber band or thick rubber band, paper, plastic bag, pencil lead, metal and plastic bottle caps, masking tape, plastic straw, wax paper, wood stick, cloth, metal ring etc.
Check Your Answers
Once you have completed this activity, check your answers below.
Conductor Testing Chart |
| Test Item | Results | Is The Item a Conductor?
|
| connecting wires | Lamp glows brightly. | Yes, wire is a good conductor
|
|
Wood Stick
|
Lamp does not glow. | No, wood is not a conductor. |
|
Paper Clip
|
Lamp glows brightly. | Yes, a metal paper clip is a good conductor.
|
| Metal Foil | Lamp glows brightly. | Yes, metal foil is a good conductor. |
| Small Rubber Band
|
Lamp does not glow. | No, rubber is not a conductor.
|
| Paper | Lamp does not glow.
|
No, paper is not a conductor.
|
| Plastic Bag
|
Lamp does not glow.
|
No, plastic is not a conductor.
|
| Cloth
|
Lamp does not glow.
|
No, cloth is not a conductor.
|
| Metal ring
|
Lamp does glow.
|
Yes, metal is a good conductor.
|