If someone asked you which material magnets are attracted to, you may respond with something like, “metal.” While correct, not all metals are affected by magnets in the same way. Even coins, while in many ways the same, can have very different degrees of response to magnetism. Why do you think some things attract to magnets and others don’t? Are things the way they are forever, or can we change how a material interacts with magnets? Let’s explore these questions and more in this very attractive activity!
While magnetism has been around forever, people only somewhat recently figured out how to harness its power. In the 16th century, Queen Elizabeth tasked her personal scientist William Gilbert with figuring out why her explorers’ compasses were failing in certain areas of the world. They knew that the problem was related to magnetism, but were unsure as to how they could solve the problem. It took significant experimentation by Gilbert to figure that this was due to the influence of Earth’s magnetism. He had to try all sorts of materials to see which were affected by magnets and which were not. Let’s recreate some of that discovery process here today.
Collect 10-15 items from around your home. Try to pick some objects that you think will attract to a magnet, some objects that will not, and some you aren’t sure. Make sure you don’t grab anything electronic. Some things that might be interesting to try are keys, aluminum foil, coins, buttons, wooden blocks, paper clips, stuffed animals, pencils, books, silverware, plastic toys, paper, and socks.
The only objects that attract to your magnet will have some iron, steel (which is mostly made of iron), cobalt, or nickel in them. There might have been some things that were made of metal that didn’t attract to your magnet. That is because they don’t contain iron, cobalt or nickel. Other metals like copper, tin, and aluminum don’t attract to a magnet. Things like wood, cloth, and plastic also do not attract to magnets. This is because of the way the atoms in different materials behave. Everything in the world contains magnetic domains, which determines whether or not something will attract to a magnet. Think of a domain as a mini piece of a magnet inside an object. Every object has lots of domains, and in most things the domains are messy and disorganized, so they cancel each other out, so they don’t act like a magnet. When things are magnetic, the domains are lined up with each other, so they can make a magnetic field. Some special materials like iron, nickel, and cobalt have domains that can switch back and forth from being lined up with a magnetic field, to messy and disorganized so they stop acting like a magnet. This is why only iron, nickel, and cobalt attract to magnets.
Now that you’ve tested objects around the house, if you can get outside, see if you can find objects out there to try this. In particular, if you have access to a yard or a park, that can be a great place to find things in nature to try. How many of the things you find in nature do you think will work? If they do attract or repel, what does that tell you about the object?
A fun thing to do now that you know all this might be to have a magnet with you and check things whenever you think of it. If you come across something you’ve never tested with a magnet before, get out your magnet and see if it attracts or repels or does nothing. Again, try to remember what that tells you about the object you tested. Also, as before, avoid testing objects with electronics since they can sometimes break if they’re too close to magnets. And while they aren’t so common anymore, if you come across a cassette or video tape, keep the magnet away from those as well since those will erase with a magnet.
This experiment was selected for Science at Home because it teaches NGSS Disciplinary Core Ideas, which have broad importance within or across multiple science or engineering disciplines.
Learn more about how this experiment is based in NGSS Disciplinary Core Ideas.