@honeste_vivere OK, thanks for your explanations, much appreciated.

I want to measure carbon, hydrogen, and oxygen. Preferably without altering the gas. The problem with sparks is that it causes oxidation. Can you excite a gas without raising the temperature?

@honeste_vivere it's not much current though. I believe neon sign transformers are limited to around 20ma. Andi t was definitely hot, if I put a stick in the middle it incinerated instantly.

I've been able to melt metals using the arc from a neon tube power supply. It is current limited but the arc is still really hot.

Thank you, this is very interesting. Although, you made the assumption that radiative transfer is negligible. Is that really so? Maybe the radiation is sufficient to even out the temperature inside?

@Chemomechanics Say it's a 1cm thick foam wall.

it doesn't matter if it's basic or not, there is no need to condescend.

What is a principal axis? How is the principal axis determined and enforced?

Isn't there some sort of kinetic energy associated with momentum though?

If the rotational impulses add up to the angular momentum, when and how does it decide to convert angular momentum to another type of energy and vice versa?

Thank you for this detailed answer. May I ask about the formula in part 2 linking velocity to temperature; what is this equation called? It looks like it's saying kinetic energy is equal to a constant of temperature, but I don't understand where the pressure inside the container fits in. Or is this v the velocity of each individual atom doing its Brownian motion?