# antigravity

You work in a patent office. One day this chap walks in with a rather large box and said he has invented antigravity. He places his box on
your trusted old spring balance and the reading is 30kg. He then presses a button on a remote control, and series of strange noises are heard coming from the box. Lo and behold, the weight has gone down to 29.5kg!
After about 30 seconds he presses his remote control again, and the reading went back to 30kg.
The box is hermetically sealed and your weighing balance is not compromised in anyway.
You said calmly,"We know that the Laws of Gravitation cannot be defied, and neither can the Law of Conversation of Mass. I know wht's going on in the box."
The Question is: What is going on in the box?
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Dear kris:

Could be a whole range of things. What kind of "balance" is it, balance beam or spring-based? How is the "remote" connected?
Saying the balance is not "compromised" means that nothing is connected to the "load".
David A. Smith
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My first guess would be something spinning inside the box.
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I guess the box is allowed to change size. It could become more bouyant. This would be so obvious to you that it would explain your calm and immediate response. the 0.5kg difference is the mass of about half a cubic meter of air, consistent with the box's rather large size.
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Dear vjkemp:

The device inside could be a vacuum pump... the box wouldn't have to change size... only not collapse if the air were pumped out (1.295 kg/m^3 at 0 degC).
David A. Smith
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Then it wouldn't be hermetically sealed. Unless you consider the inside evacuated space to be part of the outside of the box.
N:dlzc D:aol T:com (dlzc) wrote:

size.
change
0
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Dear vjkemp:
[dlzc wrote]

Good point.

Pretty slimy, but possible the *walls* of the box are hermetically sealed, sealed from both the outside, and what would be considered to be "inside" the box. Lawyers can prove nearly anything.
You can't simply compress the air into a tiny tank either, because the mass would still be over the balance pan.
I haven't seen that "kris" has shared with us the rough geometry of the box.
David A. Smith
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There are probably many ways to do this. My way would be to put an air compressor and tank in the box.
Don Kansas City
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actually whats is going on inside of the box is that it had several motors to rotate.3 magnetic rings which are smaller then each other and they rotate and in the middle of them it has a magnet ball of adifferent polarity. there for making it lighter or even heavier
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Sorry kid. Won't work.
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Magnets "attract" and "repel". The repelling action that you imply will have the "weight" of both items and NOT change the weight of the box. For every action there is a reaction. Review your laws of physics. Jim Y

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Dear Jim Y:

The problem with a nice statement like this, is that electrically powered devices, especially with magnetic fields, is that they can involve structures outside the "hermetically sealed" box. Like the balance. Or the Earth's magnetic field. And even motorized (or otherwise vibrating) devices can affect the mechanism of the balance. The "system" now includes the balance, and therefore the indication on the balance cannot be trusted.
The reason we have the concept of "impulse power" (Star Trek), is because some fellow had oscillating electric fields in a capacitor, and noted that the capacitor "weighed less" in one orientation, and "weighed more" in opposite orientation. Put it in a boat, though, and it just sits there making waves in any orientation.
It isn't antigravity, it is just interesting. A waste of time, but interesting.
David A. Smith