For the kid expecting a Lionel model train set under the Christmas tree, unwrapping a pack of copper wire, a couple of magnets and a battery is sure to disappoint.
But show them how to make a train out of those items, and you just might spark their curiosity and instill a love of science. Now that’s a gift — here’s how it works.
When you “build” the train, you are actually building an electromagnet. The locomotive — a battery with magnets on either end — moves because of a current generated by the coil pushing against the magnets. The magnets are drawing energy from inside the battery.
You might not be completely off the hook if you bestow this inexpensive DIY present upon an unsuspecting kid. But this curiously simple setup, as seen 4.6 million times on the Amazing Science YouTube channel, ought to at least distract the recipient for a while.