Magnets and Magnetic Fields
Magnets have two poles; field lines run from north to south.
About this topic
Magnets have north and south poles; like poles repel and unlike attract. Magnetic field lines emerge from north, loop around to south, and are closest together where the field is strongest. Iron, nickel and cobalt are magnetic materials.
Magnets can't be split into single poles: cutting one gives two smaller magnets. A compass needle aligns with a field, and sprinkling iron filings around a bar magnet makes the pattern of lines visible, with the filings crowding near the poles.
Permanent magnets arise from aligned atomic domains, tiny regions in which the magnetic effects of electrons point the same way, and heating or hammering can demagnetise them. Magnets are used in speakers, hard drives, fridge doors, generators and recycling plants that sort steel from other scrap.
A misconception is that magnets attract all metals; aluminium, copper and gold are not attracted. Also, the magnetic pole in the Arctic is actually a south pole of Earth's magnet, which is why a compass needle's north end points there.
Key ideas
- Like poles repel
- Compass needles align with field
- Earth is a giant magnet
Quick check
Use cases: where Magnets and Magnetic Fields helps
- Homework: review the key idea behind Magnets and Magnetic Fields before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Magnets and Magnetic Fields without notes.
- Visual learning: play with the interactive lab to see how Magnets and Magnetic Fields changes when you adjust its inputs.
- Teaching a friend: explain Magnets and Magnetic Fields in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Magnets and Magnetic Fields?
Magnets have two poles; field lines run from north to south.
What will I learn in Magnets and Magnetic Fields?
Like poles repel. Compass needles align with field. Earth is a giant magnet.
Is Magnets and Magnetic Fields part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Magnets and Magnetic Fields lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Magnets and Magnetic Fields?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.