Magnetic Fields
Describe magnetic poles (north and south), explain attraction and repulsion between poles, describe magnetic field lines plotted using a compass, and explain the Earth's magnetic field and its practical uses
What a learner can do afterwards
- States the rule for attraction and repulsion of magnetic poles
- Draws the magnetic field pattern around a bar magnet from memory or compass readings
- Explains why a compass needle points north
- Explains that the Earth has a magnetic field and describes how it is used for navigation
The lesson
You already know that magnets have a north pole and a south pole, and that like poles push apart while unlike poles pull together. That pushing and pulling happens because every magnet is surrounded by an invisible area called a magnetic field.
Field lines show the shape of this invisible area. Each line leaves the north pole, loops around the magnet, and goes back in at the south pole. You can see this pattern for real by moving a small compass around a bar magnet and marking which way the needle points at each spot.
Mia moves a compass step by step around a bar magnet. Close to the poles, the needle swings quickly and the lines she draws are packed tightly together. Further away, the needle turns more slowly and her lines spread out. This tells her the field is strongest near the poles.
The Earth behaves like a giant bar magnet buried inside it. That is why a compass needle always swings around and settles pointing roughly north: it is lining up with the Earth's own magnetic field, just like it lines up near a bar magnet.
A magnet's field lines run from its north pole to its south pole, and Earth's own magnetic field is what makes every compass point north.
Watch it
Where it sits
Learn first
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Where this leads
Jobs that lean on this skill. Follow one to see everything it is built on.
8 questions wait behind this lesson, each with its answer explained. Every answer feeds the sky: stars light as they are learned, and dim when it is time to come back.