Science at Home Videos

Announcer: Frostbite Theater presents... Cold Cuts! No baloney!

Joanna and Steve: Just science!

Joanna: Hi! I'm Joanna!

Steve: And I'm Steve!

Joanna: And this is a 'Science at Home' edition of Frostbite Theater that you can do along with us! Just download the worksheet from our website or you can record your data on a piece of paper!

Today, we're going to do an experiment with magnets!

Steve: They're two basic types of magnets: permanent magnets and electromagnets.

Joanna: Now, you're probably already familiar with permanent magnets. They're the ones that you find on your refrigerator. They act like magnets all the time, which is nice when you want to stick something on your refrigerator. But, it isn't easy to change how strong they are. With permanent magnets, you pretty much get what you get.

Electromagnets are different. They need electricity in order to work. This can be nice because, if you want it to stop being a magnet, you can just turn it off.

Today, we're going to see if we can change how strong an electromagnet is by changing how much electricity it receives.

Steve: So that we aren't counting paperclips all day, we'll make a smaller magnet for our experiment. If you'd like to make one at home, you'll need a piece of iron, like a nail, and some insulated wire. Wrap the wire around the nail a bunch of times and... that's about it.

Joanna: We'll power the magnet with some alkaline flashlight batteries and we'll measure how strong the magnet is by how many paperclips it picks up.

Steve: Each battery can provide one and a half volts, and we'll add batteries in series, so we'll eventually test the magnet with one and a half volts, three volts, four and a half volts and six volts. And, we'll test each setting twice.

Joanna: Now, if you know a little bit about batteries and electricity, you might be saying "Wait! You're doing this wrong! It's the current that matters. You should be measuring that. And, you're trusting that the batteries are providing what's printed on the label. At the very least, you should be measuring the voltage when the batteries are hooked-up to the magnet."

Steve: And, you're right. Unfortunately, we don't currently have access to all of our equipment. We have to make do with we have on hand. But, let us know in the comments if you would like us to revisit this experiment once we regain access to all of our toys.

Joanna: But, for now, if you're ready, let's start counting paperclips!

So, how did it go?

If all went well, your graph should show that the average number of paperclips picked up increases as the voltage increases.

Steve: And, assuming we can trust the voltages, we can use the graph to predict how many volts we should use if we wanted to pick up a specific number of paperclips.

Joanna: Being able to control the strength of electromagnets is important for us at Jefferson Lab. For those of you who don't know, at Jefferson Lab we have an electron accelerator that's used to study inside of atoms. Our accelerator is shaped like a race track and we use electromagnets to steer the electrons around the arcs.

Can you guess why different sized magnets are used on different pipes? Tell us what you think in the comments!

Steve: If you'd like to expand on this experiment, say, for a science fair project, they're a number of different things you could try.

First, like we already mentioned, you could properly measure the current or the voltage rather than taking the battery's word for it. You could try changing the number of coils you wrap around the nail. You could see if reversing the connection to the batteries makes a difference. How about the size of the nail? Does it matter if you use a thin nail or a thick nail? There's actually quite a bit you could do with this relatively simple set-up.

Joanna: Thanks for watching! I hope you join us again soon for another experiment!

Steve: Hey! Check it out!

Like poles repel!

Joanna: Okay! But don't get it too close to th-th-th-th...

Steve: Whoops!

Yeah...