Amazing Magnets
FoundationMagnets attract iron objects; a magnet has two poles — like poles repel and unlike poles attract; a compass needle points north and south.
- Magnets attract objects made of iron.
- Not every metal is attracted to magnets.
- A magnet has two poles: north and south.
文體小知識：說明文把知識講得清清楚楚。這一篇帶你玩磁鐵：它吸什麼、兩端有什麼祕密，還有指南針怎樣指南北。
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1Why does the little magnet on the fridge never fall off? Because there is a magnet behind it. A magnet has an invisible power — magnetism — that attracts certain things across space. Move a magnet slowly towards a paper clip: before they even touch, the clip jumps up and sticks on. How interesting!
2Do magnets attract all metals? No. Magnets attract iron-type metals, such as iron nails, paper clips and staples; a plastic ruler, a silver spoon and a wooden pencil are not iron, so magnets cannot hold them; metals like copper and aluminium are not attracted either. So being metal and being attracted to a magnet are not the same thing.
3The two ends of a magnet are strongest — they are called the poles: the end pointing north is the north pole, the end pointing south is the south pole. Play with two magnets: north pole to north pole pushes them apart — like poles repel; north pole to south pole snaps them together — unlike poles attract. Through thin paper or a thin wooden board, the magnet still holds the paper clip, so magnetic force can pass through objects.
4Inside a compass is a tiny magnetic needle — really a small magnet. Lay the compass flat and let the needle settle: the red end always points north and the other end south. In ancient times people found their bearings with compasses, so ships and travellers never got lost; today compasses are still useful for camping and hiking.
5Many everyday things use magnets: the door stopper behind the door, fridge magnets, magnetic toys, the clasp of a pencil case, magnetic buckles on schoolbags. Try a magnet safely at home and see what sticks; keep magnets away from TVs, phones, computers and bank cards, and never put small magnets in your mouth — be a safe little magnet scientist.
1Summary 重點摘要
Magnets attract iron objects; a magnet has two poles — like poles repel and unlike poles attract; a compass needle points north and south.
2Vocabulary cards Vocabulary
An object with magnetism that attracts iron things.
The power of a magnet to attract iron objects.
To pull something close and hold it, like a magnet holding a nail.
To push something away, like two like poles pushing apart.
The two strongest ends of a magnet: north pole and south pole.
A tool with a tiny magnetic needle that shows north and south.
A metal attracted by magnets, like an iron nail.
Hard, shiny material, such as iron, copper, aluminium and silver.
A small wire loop for holding paper; magnets attract it.
The way things point, such as east, south, west and north.
3Step by step Steps
- Step 1: Meet magnets and magnetismMagnets come in many shapes: bars, horseshoes and rounds — inside a fridge magnet hides a flat one. Magnets have an invisible power called magnetism, drawing certain objects towards them across a distance. Move a magnet slowly towards a paper clip and you will see it grabbed before they touch. That invisible pull is magnetic force; it passes through air, and also through thin paper and thin wood, so a paper clip can be lifted even with a sheet in between.
- Step 2: Test what a magnet attractsGather a few objects: an iron nail, a paper clip, a plastic ruler, a silver spoon, a copper coin and a wooden pencil, and test them one by one. The nail and the clip stick firmly — they are iron; the plastic ruler is plastic, not metal at all; the spoon is metal but silver is not iron; the copper coin and aluminium can are not attracted either. Conclusion: magnets attract only iron-type objects, not every metal. Chart your results and you have a fine experiment record.
- Step 3: Know the two polesDip a magnet into a pile of staples and lift: most staples cling to the two ends, fewer to the middle. The two ends of a magnet are the strongest — they are the poles. Hang a magnet from a string and let it turn freely: when it stops, one end points north and the other south; the north-pointing end is the north pole, often painted red, and the south-pointing end is the south pole. Every magnet has two poles — cut one in two and each piece still has both.
- Step 4: Like poles repel, unlike poles attractTake two bar magnets or magnetic toys: bring north pole to north pole and your hand feels a push as they shove each other away — like poles repel. Bring north pole to south pole and they snap together before touching — unlike poles attract. The same happens through a sheet of paper. Try it with the hanging magnet from the last step: bring another magnet's north pole close to the hanging north pole, and the hanging magnet swings away — proof that like poles really repel.
- Step 5: Learn to use a compassThe tiny needle in a compass is really a small magnet. Pulled by the Earth's magnetic force, it rests pointing one end north, the other south. How to use it: lay the compass flat on your palm or a table, away from phones and iron objects, wait until the needle stops completely — the red end points north. Once you know north, your back is south, your left is west and your right is east. Ancient Chinese people invented the compass to steer ships across the sea; hikers and campers still use it today.
- Step 6: Find magnets in daily lifeMagnets are everywhere: the door stopper that holds the door so it does not slam; fridge magnets and message-board magnets; the magnetic clasp of a pencil case; magnetic catches on handbags; magnetic toys and board magnets. Hunt at home and count how many magnetic items you find. Remember the safety rules: keep magnets away from TVs, computers, phones and bank cards, because magnetic force disturbs them; never put small magnets in your mouth or nose, and tidy them away after play.
5Worked example Example
Example: on the table are an iron nail, a plastic ruler, a silver spoon and a paper clip. Which will the magnet attract, and why?
- Test one by one: move the magnet slowly towards each object and watch which one is pulled over.
- The nail and the paper clip are attracted: both are made of iron, and magnets attract iron-type objects.
- The ruler and the spoon stay still: the ruler is plastic, not metal; the spoon is metal but silver is not iron, so it is not attracted.
- Conclusion: magnets attract only iron-type things; also remember the two poles — like poles repel, unlike poles attract.
- Answer: The magnet attracts the iron nail and the paper clip because they are iron. The plastic ruler is not metal, and the silver spoon's metal is not iron, so neither is attracted. Move the magnet slowly towards each object — only magnetic objects will be pulled over.
6Common mistakes Mistakes
7Quick check Quick check
Q1Can a magnet attract an iron nail?
Q2Can a magnet attract a silver spoon?
Q3Where is a magnet strongest?
Q4What happens when two north poles meet?
Q5What is a compass for?
8Recap Recap
- Magnets attract objects made of iron.
- Not every metal is attracted to magnets.
- A magnet has two poles: north and south.
- Like poles repel; unlike poles attract.
- A compass needle shows north and south.