Sat, Jan 17, 2009 - Page 13 News List

WEEKEND SCIENCE: When opposites attract 異性相吸

Welcome to Weekend Science! Every Saturday we’re going to guide you through some cool experiments that you can do at home. It’s a good idea for you to keep a record of what you do in a Science Journal. That way you can record what you learn, compare results and maybe use them to design new experiments! Remember to always ask a grown-up’s permission before trying out an experiment.



The Ancient Greeks and Chinese were the first civilizations to discover that they could make a compass from magnets. Since then, mankind has been discovering more practical uses of magnetism, and today you will find magnets in many household objects, such as headphones, refrigerators and TVs.

All magnets have two poles, north and south. When suspended by a string, the north pole will align itself with the earth’s North Pole, and the south pole will point to the South Pole.

In today’s experiment you will harness the power of magnetic repulsion to make a magnet levitate.

What you will need: two bar magnets with the poles marked, two ring magnets, a pencil, some polystyrene and a notebook.(JOHN PHILLIPS, STAFF WRITER)






Step 1: Find out what makes a magnet attract or repel. Take the two magnets and bring the two north poles together. Make a note of what happens. Now do the same thing with the two south poles.

Step 2: Reverse one of the magnets and bring two opposite poles together, ie north and south. You should now know what causes the magnets to attract and repel.





Step 1: Now we’re going to show you how to make your magnets levitate. Take one of your ring magnets and put it on a table. Bring the north pole of your bar magnet close to the surface of the ring magnet. If they attract, this is the south pole of the ring magnet. If not, it’s the north pole. Do the same with the other ring magnet.


1. magnetism n.

磁力 (ci2 li4)

2. pole n.

磁極 (ci2 ji2)

3. repulsion n.

排斥作用 (pai2 chi4 zuo4 yong4)

4. levitate v.i./v.t.

使飄浮 (shi3 piao1 fu2)

5. surface n.

表面 (biao3 mian4)

6. flux n.

通量 (tong1 liang4)

Step 2: Now get your pencil and stick it in the polystyrene block so it’s vertical. Slide a ring magnet to the bottom. Identify the opposite pole of the other ring magnet, then slide it onto the pencil. If you identified the poles correctly, the magnet should levitate a few centimeters above the other one. Show your friends your cool trick!





Around any magnetic object there are lines of magnetic flux flowing from the north and re-entering in the south. If the lines of flux are flowing in the same direction, they will link up and the magnets will attract.




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