# Tag Info

47

The balls are entering the water well below the surface. The pressure there is much higher than at the surface. The work needed to push the balls into the water at this depth cancels the work gained when they float back up. We can ignore the gravitational force on the balls since gravity pulls down as much as up as you traverse the loop. Mathematically, ...

21

If gas A and gas B are of different density, then the situation sketched is not in equilibrium: the water level on the side of the light gas will be higher. There, the containers are moving down, and you have to push your containers through this net difference in level. You do need to put in energy here, which is probably the piece that you are trying to ...

20

A simple symmetry argument might help here. Try to abstract everything away from your picture that is just a distraction. In the end it might look like this: Why should this move to the left or to the right? It cannot and therefore adding a person and wheels does not change the problem.

13

The energy needed to submerge a ball is equal to the energy gain from other ball to emerge from the water on the other side, so any waste on friction drives the process impossible.

12

The energy conservation law is compatible with every single observation we have made inside the Milky Way in science, or outside science, so the empirical evidence in favor of it is overwhelming, diverse, and universal. Theoretically, the case is also clear. Emmy Noether demonstrated that conservation laws are linked to symmetries. The validity of the ...

11

"Nature, to be commanded, must be obeyed". If perpetual motion is impossible in principle, no technology, no matter how advanced, will make it possible. By the way, perpetual is longer than any long period of time.

11

Anything can rotate infinitely, if there is no friction. Rotating an object with constant velocity uses no energy to maintain. With friction it will loose energy and eventually stop. If you add a static magnetic field to the object, it will gain some finite potential energy, which in turn can be converted to kinetic energy. Now if you add a changing ...

9

Thermodynamics does not prevent the trapping of heat. Here are limitations that thermodynamics does impose on the energy balance of the Earth: The Earth's surface can not be (passively) warmed hotter than the temperature of the sun The Earth's surface can not be (passively) cooled colder than the temperature of space Those living on the Earth can not get ...

8

The problem is in the seal. The amount of work to move the seal against the water pressure is the same amount of energy that is gained by the balls when they are pushed up by the water. Even if we remove the seal and we imagine a magic "one-way pass-through" wall, the ball would still need to displace the same volume of water as itself in order to get into ...

8

First of all, nantennas in general don't violate the second law of thermodynamics, so they are not perpetual motion machines of second kind. As long as the total entropy goes up, the second law is obeyed. In other variables, it really means that a part of the incoming heat has to heat the nantenna up but there may still be a lot of energy left for energy ...

8

You do not need to invoke friction. The magnetic forces are in equilibrium by themselves so if you place the magnets in that configuration, they will not spontaneously begin to move. The reason is that there is a corresponding force on the magnets when they are vertical that matches the ones you've already drawn. Let me make a simple model. First of all, ...

7

The second law holds on average for systems of any size, large or small. If you have an isolated contraption containing just a few atoms, and you run it through some procedure (maybe as simple as waiting 5 seconds, or maybe more complicated), there is some probability that the atoms will wind up in a lower-entropy configuration at the end of the procedure ...

6

He's basically saying assume you have some complicated system of weights connect by pulleys, and each weight can be in only one of two states: up or down. But you can trade off which ones are up and down, for example you can make 3 light weights go up by having one heavy one go down, and there are many other moves like this you can do. Now his point is ...

6

I can only hypothesize that the extra energy is due to cooling of environment. As there is some input of energy, that would not contradict the second law of thermodynamics.

6

A (non-accelerated) permanent magnet doesn't produce electromagnetic radiation. It is surrounded by a magnetic field (just like a charge is surrounded by an electric field), but it does not radiate. Especially there's no energy leaving the magnet. Note that for energy flow (as in radiation) you need both an electric and magnetic field, because only then ...

5

Coefficient of friction applicability Saying the frictional force is $kMg$, opposite the direction of motion is a particular physical model. This model is not fundamental, and is certainly not 100% true, although it works pretty well for lots of practical situations. It applies for sliding between two surfaces, and it does not apply for a rolling ball. ...

5

If you need to produce the antimatter from (e.g. electric) energy – e.g. antiprotons may be produced from collisions of proton pairs at the LHC (most of the initial, "invested" energy is the kinetic energy of the protons there) – then you're obviously not getting an economic source of energy because you're converting energy to mass and back which would be ...

5

I was surprised to see an effect that's actually real, and not a hidden motor or something like that. I believe this experiment can feasibly be repeated. The principles behind it make sense. The driving force comes from the density difference in the cup versus in the pipes. The cup has very few bubbles in it compared to the pipe. Why? Because: The ...

5

What a beautiful machine! It is obviously radiating away energy, because it is loud. I actually have a similar machine at my house. It is also a high-Q mechanical resonator with a very narrow frequency acceptance; I have compared it to standard frequency references and I believe its stability is $\Delta f/f \approx 1\times 10^{-4}$. Here's a photo of it: ...

5

The speed of any object is constant if there are no forces acting on the object. This applies to light and all other matter. Without forces (e.g. friction), an object that is moving will never stop moving. By "perpetual motion" people usually mean a machine that can produce more work than the work required to run it. It's hard to think of an everyday ...

5

See Anand's answer: I'm not sure whether this one is simply misguided or instead subtle fraud (as calls for money to fund research are involved). Actually the claims made in the article are true in one sense, which gives the idea the whiff of sophisticated fraud. In the linked article, it is claimed that the device is powered by a 1kW source and then ...

5

In addition to Bernhard's answer, just because three gases (Gas A,B and air - which is itself a mixture of nitrogen, oxygen, and other gases) have different densities, it does not mean they will remain seperated when in a container. In fact, as entropy of the system increases over time, Gas A, B and air will make an even (if heterogeneous) mixture.

4

The main point is that Newtonian gravity fields are conservative. What that means is that it is impossible to have a configuration like the one you drew without there being gravitational fields pointing to the left and to the right in the regions where you want to do the 'horizontal' transfer. For example, you might try to achieve this on Earth by taking ...

4

It doesn't appear to be fraud (as suggested on Skeptics), but rather a good joke. The YouTube video ultimately links to this disclaimer for a great little website. Apologies if I ruined the joke.

4

There is no such thing as a physical quantity that is small or large in an absolute sense. Quantities can only be small or large compared to other quantities. Furthermore, comparisons must be between quantities with the same physical dimensions (which can be unitless). For example, sometimes a velocity is much less than the speed of light: $v \ll c$, or ...

4

I'm afraid to say that unless we're considering incredibly cold superconductors (which have been known to sustain currents for years), none of these devices work. The first video offers instruction on building all manner of green devices including solar power generators and I'm not sure If it even claims to be a perpetual motion machine. I mention the other ...

4

This is because how much ever force the magnet is applying on the IRON (not any metal) is opposed by an equal force applied by the iron on the magnet! And since the magnet is a part of the vehicle, this force will cancel out the force on iron by the magnet. Magnetic force occurs both ways! Therefore, there is no NET force on the whole vehicle, which is why ...

4

If the magnet is strong enough to pull the ball up the bottom slope, it will be too strong to let the ball fall. Even worse, as you have drawn the diagram the magnet is pulling the ball down the lower slope when it is toward the left end. Anywhere to the left of where the perpendicular from the magnet to the ramp, the magnet is pulling more right than up. ...

4

The key here is the antimagnetic strip, quite aside from whether or not such a device can be built. When you insert the anti-magnetic strip, you must change the shape of the magnetic field. You must force the magnetic field to "leave" the high permeability ball. The same magnetic induction $|\vec{B}|$ in a high permeability $\mu$ material represents a lower ...

3

You might be able to get it to work for quite a while, depending on your skill as an engineer. But there is a critical difference between a well-engineered machine that runs for a while, and a perpetual motion machine that runs forever without input. The latter is impossible.

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