Lesson · Grade 7 · Science
A Moving Magnet Makes a Current
- Grade 7
- Science
- 1 min 12 s
- British Columbia
- BC7-SC-24
A coil of wire is joined to a meter, and a bar magnet with its field is pushed into the coil, held still, pulled out and then moved faster, while the needle swings one way, sits on zero, swings the other way and swings further. Four short notes build up on the right, the generator link is mentioned, and the video ends on the recap that a moving magnet makes a current and a still magnet makes none.
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In one sentence
The question this lesson answers
Can a magnet make an electric current? Let us try it with a coil of wire.
The two ends of the coil are joined to a meter. Its needle shows any current.
Transcript
What the lesson says
Can a magnet make an electric current? Let us try it with a coil of wire.
The two ends of the coil are joined to a meter. Its needle shows any current.
Here is a bar magnet. All around it is its magnetic field.
Right now the magnet is still, and the needle sits on zero. No current flows.
Now push the magnet into the coil. Watch the needle.
The needle moves. A current is flowing through the coil.
Hold the magnet still inside the coil. The needle drops back to zero. The current stops.
Pull the magnet out again. Now the needle swings the other way. The current flows backwards.
A current flows only while the magnetic field through the coil is changing.
Move the magnet faster, and the needle swings further. A faster change makes a bigger current.
This is how a generator makes electricity. Magnets and coils keep moving past each other.
So remember: a moving magnet makes a current. A still magnet makes none.
Curriculum
Where this fits
- British Columbia, Grade 7
Science, Physics: electromagnetismBC7-SC-24
Previous: A current makes a magnet: the electromagnetNext: How a Generator Works
The outcomes and strands follow the British Columbia curriculum.
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