Your friend tells you they think it would be cool to have band practice on the moon. Is it possible to hear the band play on the moon? Why or why not?

That wouldn't be possible.

Because the moon has no atmosphere, which means there is no gas, you wouldn't be able to hear it. The reason we hear sound on Earth is that the Earth has an atmosphere so there is gas in which acts as a medium for sound to travel through.

Sound though open space (and other compressible media) is composed of compression waves. Lack of any such media, such as the vacuum of space means the sound waves have nothing to propagate through. So there would be no sound. it's also virtually impossible since there's no electricity