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Water Doesn’t Destroy Magnets — But They Can Be Demagnetized
It’s no surprise that Donald Trump just says stuff to try and make a point. For him, it doesn’t matter if it’s true or not but just that it fits with his current theme. In this case, the idea was that the military was wasting money on new technology. In particular, the Electromagnetic Aircraft Launch System (EMALS). This is a new way to push aircraft on a carrier to get them up to flying speed. It replaces the previous method using a giant steam-powered piston.
Instead of steam, the EMALS uses a linear induction motor. This is basically the same as a normal electric motor except that it just pushes things instead of making a shaft rotate. It’s possible to build a linear induction motor that doesn’t even use magnets — and I’m not completely sure how the EMALS works. Let’s just assume that there are coils of wire that produce large magnetic fields to pull a permanent magnet.
One of the nice things about the EMALS is that it’s easier to adjust the force from the catapult. This means that it can be “dialed down” with lower power and allow it to launch lower mass aircraft (like drones).
But let’s not focus on the electromagnetic launcher. Instead let’s talk about magnets and Trump. Here’s the argument he made about why the EMALS is terrible. This is the fun part though:
“Now all I know about magnets is this. Give me a glass of water. Let me drop it on the magnets. That’s the end of the magnets.”
Honestly, I don’t think he thinks water destroys magnets. I mean, why would anyone think that? I suspect he’s just on his normal rant and believes that water will destroy electric stuff and magnets and electricity are the same thing (I mean, that’s sort of true).
Anyway, there’s a bunch of stuff to address. So, let’s get to it.
How do you make a magnet?
If you want to make a magnetic field, there are two main ways you could do that. It’s possible to run electric currents through a wire — this will produce a magnetic field. We call these electromagnets. It’s nice because you can turn this magnetic field on and off. Here’s an example.
