So it’s “settled Science”...?
In this case yes. Laws in physics, are theories that can be proven.
Because the ball as a vessel containing a gas, it is subject to Gay-Lussac's law. The law says that pressure of a gas in an enclosed vessel is directly proportional to it's temperature.
Notice that climate change cites no laws of physics or science in the arguments that it is "settled science". Proponents use computer modeling with arbitrarily assigned values for climate variables instead.