Just a thought but as pressure reduces perhaps sound can move more easily but has less ability to travel from vacuum through density(jar) and is reflected instead .
Has an experiment been done with a mic in the jar with the bell ?
ok, now think differential pressures and the miniscus between pressure differentials(eg waters miniscus). Similar found in double glazing.
Sound moves in water but it cannot break the miniscus , the pressure differential is too high.
The sealed airspace in double glazing acts as a miniscus to sound.
The function of the metronome proves sound is being generated in the vacuum , we just cant detect it yet.
If we see the bell oscillating and reproduce the frequency you could say sound travelled at the speed of light.
Has an experiment been done with a mic in the jar with the bell ?
ok, now think differential pressures and the miniscus between pressure differentials(eg waters miniscus). Similar found in double glazing.
Sound moves in water but it cannot break the miniscus , the pressure differential is too high.
The sealed airspace in double glazing acts as a miniscus to sound.
The function of the metronome proves sound is being generated in the vacuum , we just cant detect it yet.
If we see the bell oscillating and reproduce the frequency you could say sound travelled at the speed of light.