Science●●●●●Difficulty 3 of 5

How did Faraday turn a moving magnet into electric current?

A magnet sitting next to a coil does nothing. Move it, and current flows. That one detail powers every generator.

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You move a magnet through a coil of wire. The moving magnet changes the magnetic field through the coil, and that change pushes a current through the wire. This is electromagnetic induction, discovered by Michael Faraday in 1831, and the same principle sits inside every power station's generator.

The surprising part is the word moving. Early experiments had found that a static magnetic field has no effect on a nearby circuit: a magnet placed near a wire loop produces no current at all. The breakthrough came when Faraday showed that a changing magnetic field can induce a current. His first demonstration, on 29 August 1831, wrapped two wires around opposite sides of an iron ring. When he connected one wire to a battery, a brief current flickered in the other, and another flicker when he disconnected it. He called it a wave of electricity. Nothing flowed while the battery was steadily connected, only at the moments of change.

Faraday's iron ring, 1831
  1. Step 1: Two wires on opposite sides of an iron ring

  2. Step 2: Connect one wire to a battery

    A brief current flickers in the other wire

  3. Step 3: Battery stays connected

    No current

  4. Step 4: Disconnect the battery

    Another brief current

The man who found this had a remarkable start. Faraday became a bookbinder's apprentice at 14. With only the most basic school education, he had to educate himself. In 1813, Humphry Davy, who had damaged his eyesight in an accident, hired him as an assistant.

He found more ways to do it: slide a bar magnet in and out of a coil and a current flickers. Spin a copper disk near a magnet and it makes a steady current. Motion plus magnetism makes electricity, for as long as the machine keeps turning.

Quiz me

0/3

  1. 1.In Faraday's iron ring experiment, when did a current flicker in the second wire?
  2. 2.Why did earlier attempts with a magnet next to a wire loop fail?
  3. 3.What does Lenz's law say?

Recap

A changing magnetic field pushes a current through a circuit, and the push grows with how fast the field changes.

💡 A trick to remember it · No wiggle, no current: electricity comes from magnets that move or change.

Surprising fact · A magnet that just sits near a coil makes no current at all; only a changing field does.

Sources (4)

No source, no claim. Every fact in this lesson (17 claims) cites at least one of these.

  1. [1]Michael Faraday · Wikipedia
  2. [2]Faraday's law of induction · Wikipedia
  3. [3]Electromagnetic induction · Wikipedia
  4. [4]Maxwell's equations · Wikipedia
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