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12

The boiling water is converting liquid water to gas. Unless this gas is continually removed by the pump, it quickly increases the pressure inside the vessel. This increased pressure will stop the boiling. Setting a lid on the jar gives it a one-way valve. Gas can still escape. If you instead put on a full seal so that gas cannot escape, then it will ...


6

Ever since Newton and the use of mathematics in physics, physics can be defined as a discipline where nature is modeled by mathematics. One should have clear in mind what nature means and what mathematics is. Nature we know by measurements and observations. Mathematics is a self consistent discipline with axioms, theorems and statements having absolute ...


5

Internal friction in the metal of the bell eventually will bring the ringing vibrations to an end. The bell vibrates when it rings, making its molecules more energetic and creating heat. Bonding between the molecules of the bell resist the vibrations, and eventually the strength of the molecular bonds will create enough friction to bring the vibrations ...


4

Anything that "suspends" the bell - whether it be a bolt, a piece of string, or a magnetic field - is applying a force. When the bell vibrates, this vibration will be transmitted. This is because the force of a magnet is a function of position - you can only get magnetic attraction because of a divergence of the field, so if you move, the force changes and ...


4

The conductivity of the vacuum is not a very trivial issue. In fact, depending on how you look at it, it behaves in two different ways. Firstly, there is no retarding force on any charged particle with constant velocity in vacuum. To this extent, no extra work is required in maintaining a constant current through any surface in vacuum. In stark contrast ...


4

Yes, the vacuum energy of a spacetime lattice with finite spacing and periodic boundary conditions within a box of finite size is finite. One would not call this "quantizing", though, rather discretizing because we are not carrying out any "quantization procedure" in the sense of going from a classical to a quantum system. In this approach, the finite size ...


4

if space has an edge, there are many ways in which you can put boundary conditions. For instance, if you make it perfectly reflective, the universe will conserve energy but not linear momentum. You can also make objects disappear at the edge so no quantities are conserved. Or you can make the objects or particles to reappear at the opposite side of the ...


2

To understand this one shall take in quantum-mechanical approximation method namely perturbation theory into account. In perturbation theory, systems can go through intermediate virtual states which often have energies different from that of the initial and final states. This is because of time energy uncertainty principle. Consider an intermediate state ...


2

No, in the very basic sense it is not a good conductor, because very high voltages are required to shoot them through. But yes it still is a conductor, because it allows the flow of current. Compare this to a diode, which similarly only allows current (in the same very basic sense) to flow if a certain voltage is applied. Such non linear behaviour exceeds ...


2

Usually we think of space as not having a boundary. Either because it is infinite, or because it is a compact surface (such as a three sphere). I rather think GR will not work on manifolds with boundaries. Furthermore, the concept of "nether" is a physical concept not known to me.


1

You correctly assumed that sound in space does not propagate ( the density of gas molecules is between 1 per cubic meter and 1 per cubic centimeter, too low to efficiently propagate sounds ). But the Camera is mechanically attached to the space suit, which contains various mechanical parts, like a thermal control system to manage the temperature inside the ...


1

I know this question is technically already answered, but there were several things missing from the answers that I thought should be mentioned (I am writing a review paper comparing different regions of space so I had these numbers at hand already as well). The speed of sound in space has multiple meanings because space is not a vacuum (though the number ...



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