P3 Magnets (Concept Map)
Primary 3 Science — Concept Map
Created by Miss Clarissa Ng · www.clartutors.com
A magnet pushes or pulls
What magnets do, how to tell one from an ordinary metal, and how to make one
A magnet can push or pull, is made of iron or steel, and a freely suspended magnet rests north-south.
Unlike poles attract, like poles repel — and only a magnet can repel another magnet.
Magnets attract magnetic materials (iron, steel) but not wood, plastic, glass, aluminium or copper.
Magnetic strength is greatest at the poles, and is compared by counting what a magnet picks up — not by its size.
Make a magnet by stroking it with a magnet, or by passing a current through a coil around it.
What a magnet is
Iron or steelmagnets can be made of iron or steel, in shapes such as bars and rings
Naturally occurringa naturally occurring magnet is called a lodestone
What it attracts
Magnetic materialsmagnets attract objects made of iron or steel
Not magneticwood, plastic, glass, aluminium and copper are not attracted to magnets
Poles and direction
Two polesevery magnet has a north-seeking pole and a south-seeking pole
Which way it restsa freely suspended magnet comes to rest pointing north-south
Where the poles arethe poles of a bar magnet are at its ends, and they are its strongest part
Attract or repel
Unlike poles attractwhen unlike poles face each other (N-S), the magnets attract
Like poles repelwhen like poles face each other (N-N or S-S), they repel
Testing a metal barif one end is pushed away by a magnet, the bar is itself a magnet
Comparing strength
Count what it picks upthe more objects a magnet can attract, the stronger it is
Size does not matterthe size of a magnet does not decide its magnetic strength
Making a magnet
Stroke methodstroke a piece of iron or steel in one direction with a permanent magnet
Electrical methodiron or steel becomes a magnet when current flows through a coil around it
What makes it strongermore coils of wire, or more batteries, make this magnet stronger
Losing magnetism
How it is losta magnet loses strength when heated strongly, dropped repeatedly or hammered