Idea 2of 7Builds onTwo ends, never one
The invisible map
A compass turns near a magnet. What is it reading?
Today you'll discover
- what fills the space around a magnet
- why a compass turns with nothing touching it
- a direction at every point
Think firstA bar magnet. A compass nearby turns
A compass held near a magnet turns, though nothing touches it. What is in the space between?
Decide first, then press Next. Watch the needle settle, then move the compass.
A bar magnet with its north end shaded. After a prediction, a small compass appears near it with its needle settled in one direction, then the compass is moved beside the pole and points a different definite way. The last step asks which way a compass beside the north pole points.
See the whole ideathe big idea and the key word, in one place
The big idea
A magnetic field fills the space around a magnet.
Easy to get wrongPoles are not charges. A north pole does not shed anything; the field is a pattern in the space, not stuff flowing out of the metal.
Key word
- magnetic field
- the region around a magnet or a moving charge where a magnetic force is felt; it has a direction and a strength at every point
About this modelField lines are closed loops that never cross; a compass needle lies along the line where it sits.
Field lines are closed loops that never cross; a compass needle lies along the line where it sits.
Ready to use it?
- Say which way a compass points at a described spot near a magnet, and why.