Now that you have learned about sound waves and the media through which they travel, can you answer the age-old question: “If a tree falls in the forest and no one is around to hear it, does it make a sound?
If sound is vibrations, then the falling tree certainly does make a sound, because it produces vibrations in the air. ... So if sound is what we hear, and no one is around to hear the tree fall, then it doesn't make a sound!
