Idea 4of 7Builds onWhere the lines crowdThe flow
Every current wraps a field
A switch closes and a compass twitches. Why?
Today you'll discover
- what a current makes around itself
- why copper can act like a magnet
- the twitch that joined two sciences
Think firstA copper coil, a compass beside it, a switch
The switch closes and current flows in the copper coil. What does the compass do?
Decide first, then press Next. Watch the field appear with the current and vanish without it.
A row of loops of wire across the picture with a wire in at the left and out at the right. After a prediction, arrowheads for the current appear, then straight field lines through the inside of the coil with a north end marked. The last step opens the switch and asks what the compass does.
See the whole ideathe big idea and the key word, in one place
The big idea
Every current wraps itself in a magnetic field.
Compare themCopper is not magnetic. Copper carrying a current is. The field belongs to the moving charge, not the metal.
Key word
- electromagnetism
- the link between electricity and magnetism: every electric current produces a magnetic field around itself
About this modelConventional current, right hand: fingers with the current, thumb along the field inside. Reverse I and N swaps ends.
Conventional current, right hand: fingers with the current, thumb along the field inside. Reverse I and N swaps ends.
Ready to use it?
- Say what a compass does when a current nearby is switched on, off or reversed.