☯ Concept Cartoons ☯
Table of Contents
1 Chemistry Option A Magnets 12 - What are magnetic field lines?
Have you talked about your ideas? Do you agree with any of the characters or do you think something different? Do you all have the same ideas? Here are some ways of finding out more. Get some iron filings in a clear plastic envelope and shake them around a magnet. Discuss what patterns you can see. Check what you see on the internet or in a textbook. Put two magnets close together and shake iron filings around them. What happens when the magnetism from the two magnets meet? How is magnetism different from a force like friction? What other field forces can you find out about? Safety note: Don't use loose iron filings - they can cause serious damage if they get into your eyes. Only use them when they are sealed in a container or packet.
Here’s what a scientist might say. Did you find any evidence to support or justify these ideas? Are there any questions that you still need to answer? There is an invisible magnetic field around any magnet. The strength of the field depends on the distance from the magnet. Scientists use magnetic field lines to show how strong the field is, but they don’t really exist. The field lines are drawn close together to show where the field is strong, and far apart where the field is weak. They are like contour lines on a map, that show how high something is but don’t exist in real life. The magnetic force is everywhere around the magnet, not just where the lines are drawn. Iron filings in the magnetic field act like little magnets. When they can move a bit they are attracted to the other filings and line up like a string of tiny magnets, but they are not following any real lines. Sometimes the Earth is said to be like a giant magnet. Draw a picture to show what the Earth’s magnetic field is like, and create a list of reasons why this is important to us. Write a newspaper report about what might happen if this magnetic field disappears.