Question

Sam's father and mother are astronauts. Last month they returned from a tour to the moon. Sam's father told him that they had an air-filled helmet and it also had a microphone, which they used for talking to each other. But his mother was not able to listen to him when they opened their helmets. (Assume they were wearing oxygen masks when they opened their helmets). What is the reason?

Answer 1

Explanation:

1. Sound waves, unlike electromagnetic waves, require a medium to propagate. They cannot travel in vacuum.
2. Here, on Earth, we are able to hear sounds clearly because of the air. Sound waves travel through the vibration of air particles.
3. Even when you are inside water, you can hear the sound because water acts as a medium for sound waves to travel.
4. But the moon has no atmospheric pressure. There is no medium for sound to travel on the moon.
5. When they use the air-filled helmets attached with a microphone, they can hear each other because the air inside the helmets provides sound waves as a medium to travel.

Hence, his mother was not able to listen to his father when they opened their helmets.