Hi
I suspect the guys in the ISS using one of these three technologies to fake zero G conditions:
I don't. I suspect that would be so horribly hard to fake using that, if not entirely impossible.
1) Diamagnetism : every body containing water is magnetic : it is very light but it's there. So using a very high power magnet, one can levitate living things like frogs and strawberries, and even humans. Faraday was the first to propose such technology back in the day.
Yet the metal objects they use would interact with the magnet in completely different ways.
In fact, just 2 different objects with water would act in a different way.
They would need to set the magnetic field strength such that the force produced by the diamagnetic material just cancels out the force of gravity.
Too little water, you fall and instead it would just be low gravity. Too much, you go flying to the top.
And that applies to the individual things that make up an object.
So no, that wont work.
2) static electricity : you remember the old times of CRT screens? they would attract tiny specks of dust and even light papers. This is supposition number 2 : we are attracted to the ground on the same principle. Atmosphere has difference of potential the higher you get, and it is a good indication that something like that could exist.
No. We are not attracted to the ground based upon static electricity. If that were the case why do we accelerate at the same rate? Why doesn't a capacitor (or charged plates) tilt to or from Earth?
Electrostatic fields do not offer stable levitation.
If you move slightly out of just the right spot, you either fall or fly towards whatever is keeping you up.
3) sound : sound can be used ot levitate anything. Of course we would hear it might you say. well there is two answers to that. First it is possible to remove the sound totally by processing an out-of-phase signal of the sound thus removing only the sound you don't want (for example in audio you can remove the center of the stereo field by just mixing the left and the right (but with the right out of phase). The other answer would be that the sound frequency is so low that human can't hear it and microphones can't process it.
This would act like wind. After all, that is basically what sound is, pulses of wind, moving back and forth (at least in air).
Also, it requires generating a standing wave where the object is trapped in a node.
So they wouldn't be able to move around.
All of these would be much much much harder to pull off than to just go to space.