What it shows
When a coil turns in a magnetic field, the changing magnetic field through it induces a current (Faraday’s law). The current reverses every half turn, which is alternating current.
This idea has a short entry only. For the science behind it, read the sentence above with your textbook and ask your teacher to explain the law or idea it shows, so you can describe it in your own words.
Materials
- Enamelled copper wire for the coil
- Strong magnets
- A wooden or plastic frame and an axle
- Slip rings and brushes
- A sensitive galvanometer, or a multimeter on a low AC voltage range (an LED needs a much faster spin to light)
Safety
For this project: Strong magnets snap together and can pinch fingers, and they can damage phones and bank cards. Keep fingers clear of the turning coil.
Never use mains electricity: power models with cells, batteries or a low-voltage adapter. Sharp and hot tools, flames and lab chemicals need an adult or your teacher beside you. Keep magnets, button cells and small parts away from young children, and wash your hands after making.
How to go about it
Numbered steps have not been written for this idea yet. Plan it with your teacher: sketch the design with measurements, build one part at a time, test each part, and write every observation with the date. The free ebooks below have step-by-step projects of the same kind.
Free ebooks for this project
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Physics Working Models Explained
Twenty classic models, how each works and how to make it
Find out more about physics
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