What are some cool home projects you can do with magnets?

Great question, Kai. There are loads actually! Magnets are the closest thing to real-life magic you can have.

Here are my three favourite projects that’ll help you understand more about it hands-on.

1. Build a motor – A battery, a nail, a copper wire, and a magnet. That’s it. Stick a small neodymium disc magnet to the flat head of an iron nail, and hang the nail’s point from the negative end of the battery (could be an AA). The magnet holds it there against the battery’s steel end. Now touch a copper wire from the battery’s positive end to the side of the magnet. The nail starts spinning! Current runs down through the nail and out through the magnet, right through the magnet’s own field, and current crossing a magnetic field gets a sideways push called the Lorentz force. It’s the same push that turns every electric motor, just without the gearbox. It all heats up fast (the battery, wire, and magnet all get warm), so keep each spin short. Then flip the magnet over, and guess which way it’ll spin before you look. Here’s a more detailed explanation on how to build the motor.
2. Drop a magnet thru a non-magnetic cylinder – Take a long copper or aluminium pipe and drop a strong cylindrical magnet down it. It drifts down like it’s falling through honey. So what’s happening here? Neither copper nor aluminium is magnetic, so what’s slowing it? As the magnet falls, its field sweeps through the metal, and that changing field sets up swirling currents in the pipe called eddy currents. Those currents make their own magnetic field. And that pushes back against the fall. The pipe, in a sense, hates change, and the faster the magnet moves, the harder it pushes back.
3. Watch an invisible field – Guess you might’ve already tried this, but this was my first ever magnet experiment as a kid. Pour some iron filings into a paper tray or a sealed plastic bag, slide the magnet underneath, and the filings line up along the field lines, like thousands of tiny compass needles. Then you can also try two magnets with their ends facing, first attracting and then repelling, and watch the pattern snap into a completely different shape. Keep the magnet under the container so the filings never touch it. Trust me, you don’t want to spend an evening picking filings off a neodymium magnet.

Neodymium magnets snap together hard enough to pinch skin, and bigger ones can even break a finger. They’re brittle too. So two magnets slamming together can break and chip. So be safe and wear eye protection. If anyone has a pacemaker or an implant around, keep the magnets away from them too.

Have fun with it, and if you build the spinning nail, post a video of it here! Stay curious.