The big idea driving this unit
At a junkyard, a giant crane swings over a pile of scrap cars, lowers a massive disc, and lifts an entire car body straight up without any claws, hooks, or straps. Then, with a flip of a switch, the crane operator lets the car drop exactly where they want it. How can a machine grab heavy metal without touching it, and then let go on command?
Chapters in this unit
- 1 MagnetismHow can a refrigerator magnet grab a metal spoon from an inch away, and why does a compass needle always swing around to point north no matter where you are on Earth?
- 2 Electromagnetic FieldsHow can a giant crane at a junkyard lift an entire car with a magnet one second, then drop it exactly where it wants a moment later? The secret is that electricity can create magnetism you can switch on and off.