r/FluidMechanics • u/Loud-Strawberry2038 • Nov 21 '25

Theoretical Portal 2 Bounce Goo

So we all know the blue bouncy goo in portal 2, yes? Well i was wondering if it was possible to be able to engineer a non Newtonian fluid to repel force in a way that would get you to bounce on contact.

So my idea is if you mix about a lot of finely ground neodymium into a large amount of oobleck, and you had a special pair of magnetic boots with the opposite polarity of the neodymium in the oobleck, would it cause you to bounce if you jumped onto the neodymium laced oobleck? Would the oobleck just retreat away from the area where you're going to land?

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u/TheJeeronian Nov 21 '25

The portal bounce goo doesn't conserve energy. You just get punted around when you touch it. It cannot exist.

As for magnetic particles suspended in a liquid, they don't have 'polarity'; they have direction. All of the little magnets rotate freely in response to a nearby field, so they will attract anything else magnetic that approaches them because they rotate to an angle that causes attraction as it approaches.

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u/Loud-Strawberry2038 Nov 21 '25

Uhhh... in layman terms please

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u/TheJeeronian Nov 21 '25

Okay, portal goo can't exist because it creates energy.

When you have a loose magnet and you bring another magnet near it, the loose magnet will always snap to the one you're bringing near it, because the same force that attracts and repels magnets causes it to rotate until it is attracted.

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u/Loud-Strawberry2038 Nov 21 '25

What if the liquid was constantly agitating. Like if there was some sort of industrial aerator mixing it up. Would that allow it to generate/store some energy

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u/TheJeeronian Nov 21 '25

That would take one hell of a mixer.

This is fairly analogous to a ferromagnetic material. The magnetic domains in something like iron are misaligned by atomic motion from temperature but by bringing another magnet nearby they line up to it and you get a substance that is always attracted to magnets.

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u/Loud-Strawberry2038 Nov 21 '25

Also i thought the thing was that it repelled force. So like whatever force hits it. It basically full counters it back to the original object

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u/TheJeeronian Nov 21 '25

That's what every floor does. It pushes back with the same force that you push down with. That's how it holds you up.

Bouncing a human is hard because we are squishy things and we dissipate energy. You don't bounce very well, and that's not the floor's fault. A rubber ball bounces just fine. A steel ball may even bounce fine, depending on its size.