Lesson 1 of 14
A wire warms up
Show on a big screenA torch bulb is warm to touch after a while.
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Step 1 of 3
- The loop is closed. Nothing is warm yet.
- The connecting wire warms a little.
- The bulb's thin wire warms far more. It glows.
The rule
Electric current is the flow of electricity in a wire. It warms any ordinary wire it flows through. This is the heating effect of electric current.
Give two wires the same current. The one that is harder to get through warms more. This hardness is its resistance.
A longer or thinner wire is harder to get through. So it has more resistance and warms more.
Nichrome is an alloy, a mixed metal, used in heaters.
Change one thing. Keep everything else the same.
| Change | Warming |
|---|---|
| More current | More |
| More time | More |
| A longer wire | More |
| A thinner wire | More |
| Nichrome instead of copper | More |
Try the lab to finish this lesson.