Magnet poles: attract or repel?
Bring the poles of two bar magnets together in different pairs and at different distances, and find the rule for attraction and repulsion.
Core concept
Like poles repel and unlike poles attract; the force gets weaker as the magnets move apart
Topic: Magnetism
Every magnet: An object that pulls iron and steel towards it. All key words has two ends called pole: One of the two ends of a magnet (north and south), where its pull is strongest. All key words, where its pull is strongest: a north-seeking pole (N) and a south-seeking pole (S). A freely hanging magnet turns so that its N pole points north. When two magnets are brought together, unlike poles (N and S) attract each other and like poles (N and N, or S and S) repel. The magnetic force: A push or a pull. Forces can start, stop or turn things. All key words acts without touching, and it gets much weaker as the magnets move further apart. Repulsion is the only sure test that something is a magnet.
What you will learn
- Identify the poles of a magnet.
- State the law of magnetic poles: like poles repel, unlike poles attract.
- Describe how the magnetic force changes with distance.
Before you start
- Know that magnets attract some metals.
Materials
- Two bar magnets with marked poles
Equipment
- Small trolley or a pencil-roller to let one magnet move freely
Procedure
- Put a north pole facing a south pole 2 cm apart and record what happens.
- Turn a magnet round so two north poles face each other, then two south poles.
- Move the magnets from 1 cm to 5 cm apart and compare the force.
How this simulation is simplified
- The force follows a simple inverse-square model, 2 N at 1 cm.