1There's all kinds of fun things you can do with a couple of magnets.
2Like the kind you might see on a fridge.
3For example, here's something I've always liked to do since I was a kid.
4You can put one magnet on a tabletop and one underneath the table
5to make, kind of like, a magnetic race car that appears to move on its own.
6That's just one of the incredible properties of magnets.
7The invisible pulling force between two magnets
8can go right through the material the table is made of.
9So it almost looks like magic.
10Have you ever played with magnets?
11What did you do and what interesting things have you noticed about magnets?
12If you've not played with magnets much before I hope you'll try.
13There's so many things you can notice when you do.
14For example, one thing you can experiment with
15is to find out what kinds of materials magnets attract or pull.
16They definitely don't attract everything.
17They do attract other magnets of course.
18And given that they stick to refrigerators,
19they definitely attract the metal that refrigerator doors are made of.
20But do they attract every kind of metal?
21Copper is an orangish, pink color metal.
22Try holding a magnet up to a piece of copper metal
23or you might've noticed that magnets come in different strengths.
24There's the really thin refrigerator magnets which can lift up like maybe a paperclip
25but there's much stronger magnets than that too that can lift some pretty heavy weight.
26Some in fact are strong enough that you have to be a little careful.
27You don't want to get your fingers pinched when it pulls something toward it.
28And you might have noticed that if you take two magnets and turn them just the right way,
29magnets don't just pull but can push each other apart.
30Instead of attracting, they repel, which feels so cool.
31With donut-shaped magnets, try putting them on a pencil.
32If you get them to repel, you can make them hover.
33So magnets are amazing, no doubt about that
34but how do we even get magnets in the first place?
35Where do they come from?
36How are they made?
37Well, it used to be that magnets weren't made at all.
38The very first magnets that anyone knew about were natural magnets called lodestone or magnetite.
39It's a rare type of rock found only in a few places on earth.
40It looks like a rock
41but it has the ability to invisibly pull or attract other lodestone to it
42as well as certain kinds of metal.
43The thing is, these natural magnets tend to be fairly weak
44but before long people notice that the invisible force of a lodestone
45can be transferred from a lodestone to a piece of iron or steel,
46making the iron or steel itself into a magnet.
47This is something you can try on your own using magnets you have.
48Simply take a steel paperclip and rub it across the surface of a magnet a few times.
49Before long, the paperclip itself becomes a magnet.
50One fun thing to try is to make a chain of paperclips connecting to each other magnetically
51and see how long the chain gets before the magnetic force becomes too weak.
52When you make a magnet this way,
53this magnetic force still tends to be pretty weak
54but eventually it was discovered that it's possible to make even stronger magnets by using electricity.
55About 200 years ago scientists discovered that there's a strange connection between electricity and magnetism.
56That's something you'll learn more about in middle school and high school.
57But by learning more about this connection between electricity and magnetism,
58that's one reason we've been able to figure out how to make magnets
59and how to make strong magnets too.
60This is actual video footage of real magnets being made today.
61The process starts by mixing together certain combinations of metals
62which have been discovered to work really well like a mix of iron metal
63plus other metals like a metal called nickel and a metal called cobalt.
64In factories, they mix these metals up by first heating them to be molten, almost like lava.
65Then pouring the molten metal into the shape that they want.
66Then once the molten metal mixture cools and becomes hard,
67they put it in the presence of a strong electrical current.
68This is the part that makes the metal mixture become magnetic.
69Now they've just made a strong magnet.
70It may seem like a lot of trouble to go through just for some magnets to put on your refrigerator.
71But while magnets are fun to play with,
72they don't just make them for hanging things on your refrigerator.
73There's all kinds of things we use magnets for.
74Magnets used in door and cupboard latches to make a door or a cupboard close shut.
75Giant magnets used in junkyards to help pick up old cars or any heavy objects made of steel.
76There's even some trains like this one called a Maglev train
77which is short form of magnetic levitation.
78There's a set of powerful magnets in the track that push the train up
79so that it's actually floating above the track.
80Then there's a second set of magnets that makes the train move forward.
81And when a Maglev train is running,
82watch what happens if you line up paperclips up on the floor of the train,
83whoa, you see it really is running on magnetic force.
84Magnets like the kind used in Maglev trains and the ones used in junkyards
85are a special kind of powerful magnet called an electromagnet,
86they're magnets that can actually be turned on and off using electricity.
87What other useful things could you do with a strong magnet that could be turned on or off?
88I'll leave you with that to think about.