Which things carry current?
Metals make the lamp glow. Others do not.
The electrician
An electrician's screwdriver has a plastic handle, and the electrician wears rubber gloves and shoes at work.
Why do you think the handle and the gloves are not made of metal?
What this lesson covers
The idea
Materials that let electricity flow through them easily are good conductors and those that block its flow are poor conductors; metals are good conductors of electricity, while sulfur, coal and wood are poor conductors.
The electrician
An electrician's screwdriver has a plastic handle, and the electrician wears rubber gloves and shoes at work.
Why do you think the handle and the gloves are not made of metal?
- Metal would let current pass through to the electrician
- Metal is too heavy
- Rubber looks nicer
Does the lamp glow?
Put each material in the gap of the circuit. First guess: will the lamp glow? Then look.
Good and poor conductors
Materials that allow electricity to flow through them easily are good conductors of electricity. Materials that do not allow it to pass are poor conductors. Metals are good conductors; sulfur, coal and wood are poor conductors.
All the materials that made the lamp glow were metals. The plastic on a screwdriver and the rubber of gloves are poor conductors, so they protect the electrician from an electric shock.
- Lamp | Material | So it is a...
- glows | aluminium, iron, copper | good conductor of electricity
- stays dark | sulfur, coal, wood, stone, eraser, nylon rope | poor conductor of electricity
Notes
Metals are good conductors of electricity. Sulfur, coal and wood are poor conductors, as are stone, eraser and nylon rope.
Check yourself
Which group makes the lamp glow?
Rubber gloves protect an electrician because rubber is a...
A material that allows electricity to flow through it easily is a...
All the materials that made the lamp glow were...
- Sulfur, coal, wood. These are poor conductors. The lamp stays dark.
- Aluminium, iron, copper — correct. Yes! These are metals, good conductors.
- Stone, eraser, nylon rope. These are poor conductors. The lamp stays dark.
- good conductor of electricity. A good conductor would let the current reach the electrician.
- poor conductor of electricity — correct. Yes! Current cannot pass through it easily.
- metal. Rubber is not a metal.
- good conductor — correct. Yes!
- poor conductor. A poor conductor does not let it pass easily.
- brittle material. Brittle describes how a material breaks, not how it carries current.
- metals — correct. Yes! Metals are good conductors of electricity.
- wooden things. Wood is a poor conductor.
- soft things. Softness has nothing to do with it.