Carrying warmth, and carrying the loop
A steel spoon gets hot. A wooden spoon stays cool. Why?
Step 1 of 3
- A steel rod, flame at one end. A circuit with a pencil core.
- Warmth moves along the rod, bit by bit.
- The handle warms. The bulb lights through graphite too.
Steel carries heat along easily. Dry wood carries very little.
Here, warmth means heat. The loop means an electric circuit.
The rule
Metals carry warmth and the loop well. Graphite carries the loop too.
Dry wood carries neither well. That is why a pan may have a wooden handle.
A material that lets warmth or the loop pass is a conductor. Metals are good conductors.
The pencil core
The circuit's grey core is graphite. Graphite is not a metal, yet it carries the loop.
Now try it. Put each material in the gap. Does the bulb light?
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