... in the forest and there is no one to hear it, does it make a sound?

What is "a sound"?
The falling tree would start a series of pressure waves in the air around it. An ear would interpret those waves as sound.
A microphone would interpret them as vibrations on a pick-up and would convert them to an electrical signal.
A camera is not designed to pick up pressure waves so would "hear" nothing.
But in space no-one can hear you scream...There isn't any sound unless there is someone/something to recieve it.

What is "a sound"?
The falling tree would start a series of pressure waves in the air around it. An ear would interpret those waves as sound.
A microphone would interpret them as vibrations on a pick-up and would convert them to an electrical signal.
A camera is not designed to pick up pressure waves so would "hear" nothing.
Correct. There isn't any sound unless there is someone/something to recieve it.
Without hearing it "sound" is just a pressure wave. It takes an ear/listening device to convert it into sound.