Page 104 - Physics_Form_2

Physics for Secondary Schools

3. Gently push one end of the magnet so that it slowly spins and comes to rest.
Note the direction in which the magnet’s north pole is pointing.
4. Push the magnet again and wait for it to come to rest.
5. Place a block of wood in a pan of water and lay the bar magnet on top as shown
in Figure 3.8. Note what happens.

FOR ONLINE READING ONLY
Bar magnet
Wood

Water

Figure 3.8
Questions
(a) Did the iron filings stick to the magnet while picking up more filings?
(b) Did the magnet always point in the same direction?
(c) Compare the direction of the suspended magnet with that of a compass needle.
Does the magnet line up with the compass needle?
(d) Describe your observations.

Some of the properties of magnets and magnetism include:
1. All magnets have two poles, the north and south poles.
2. Magnets exert a force on some materials and do not on others.
3. Magnets attract ferromagnetic materials such as iron, nickel and cobalt.
4. The magnetic force is an action-at-a-distance force.
5. In a bar magnet, more iron filings stick to the poles, meaning that the magnetic
force is the strongest near the poles of a magnet, and that the poles have equal
strength.
6. When two magnets are brought together, like poles repel each other while unlike
poles attract, as shown in Figure 3.9. This is the basic law of magnetism.

Repulsion

Attraction

Repulsion Attraction
Repulsion

Attraction

Figure 3.9: Attraction and repulsion of magnetic poles

98
Student’s Book Form Two

Physics Form 2 Final.indd 98 25/10/2025 10:26