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Everyone’s familiar with magnets. You probably have some on your refrigerator right now. I bet you know the basics: magnets stick to some things and not others, and they can stick to each other, too. But magnets, like so much else in science, are more complicated than they may appear. Today’s activity is a quick experiment with magnets to see what they attract, what they don’t, and try to figure out why. To do so, we’re going to go fishing!
Materials
- A long stick
- Some string
- A magnet
- A bunch of random objects (coins, nuts and bolts, paperclips, bouncy balls, Lego bricks, twigs, tin foil, pens and pencils, etc. just to give a few examples
Process
- First, you need a fishing pole. Tie your magnet to one end of your string, and tie the other end of your string to one end of your stick.
- Now it’s time to make your fishing hole. Put all of your random objects into your clear plastic container. For some extra authenticity, pour some water in on top of them.
- Before you go fishing, make some predictions. Which of your objects do you think you’ll be able to catch with your magnetic fishing pole? Which do you think will remain in the fishing hole because they aren’t attracted to magnets?
- Go fishing! Dip your magnet into your sea of random stuff and try to pick up one or two things at a time. When you get one, pull it out and examine it. What does it look like? What is it made of? What about it do you think made it stick to the magnet?
- When the only things left in your fishing hole are objects that won’t stick to the magnet, make some observations about them. What are they like? How are they different from the objects that did stick to your magnet?
- Dry off all of your random objects. If any have iron in them, they might rust if you leave them wet!
Summary
How did your predictions do? Was there anything that you expected to stick to the magnet that didn’t? Anything you thought wouldn’t stick that did?
If you’re like a lot of people, you might have predicted that all of the metal objects would stick to your magnets, and then discovered that some of them, like coins, didn’t stick at all. This is because only a few metals are actually ferromagnetic, meaning they are attracted to magnets. The “big 4” are iron, nickel, cobalt, and manganese, all of them elements on the periodic table. You can mix these metals with other substances to create alloys, and many of those alloys will also be magnetic. One of the most common ferromagnetic alloys out there is steel, made by mixing iron and carbon.
Other metals are not ferromagnetic. Copper, which is mostly what quarters, nickels, and dimes are made of (even though they look silvery) is not magnetic. Zinc, which is most of what pennies are made of (even though they look coppery) is also not magnetic. This has to do with the atoms that make them up and how their electrons are arranged. Only certain electron arrangements allow a substance to be ferromagnetic.
As a general rule, only metals can be ferromagnetic. The plastic magnets you might have on your refrigerator are actually made of a special plastic mixed with a metal that is then turned into a magnet. Some scientists doing cutting edge research have figured out how to make certain kinds of plastic magnetic, but right now that kind of thing is still being worked on in labs.
Now that you know a big about magnetism, take your fishing pole around the house and see what other ferromagnetic objects you can find!
Want more experiments? See all of our at-home activities on the blog or Pinterest.
