Can you hear sound in space? In this video I put a speaker in my vacuum chamber along with a diaphragm with vibrating salt to see what happens when I suck all the air out of the vacuum chamber. The pressure waves vibrate the salt when there is air in the chamber, but once it is mostly gone the diaphragm stops vibrating even though the speaker is still playing! I play a sine wave at 800 Hz to get the salt vibrating. At full vacuum I didn't see any salt vibrating at all. This is a good example of why you
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