Today I attended the Day of Scholarship. On my drive to school I was telling my best friend about it and she seemed very excited as well. She was telling me about how one of her friends from her singing group was presenting his project that he had been working on for a long time and that it had turned into this very big and complicated thing. Then she tried to explain it to me and with the lack of her science background, it turned out to be a really funny and confusing explanation. But she raised some interesting points that I had to go find out what this was all about.
The name of the project was Investigating Underwater Acoustics and it was about how sound could travel faster in water because the molecules are closer to each other and therefore sound can bounce off of them at a faster rate and travel faster. The presenter was explaining how that’s why in the old times when people wanted to hear when their enemies were coming in a war, they would put their ears on the ground because sound travels even faster through a solid material whose molecules are even closer and therefore the generals would be able to tell how far away the enemy is and how fast they are approaching. I thought that was really interesting.
Then he went on and talked about how at a certain frequency the wavelength of a wave is as long as the length between our two ears. At this frequency then, we have a hard time locating where the sound is coming from. In other frequencies, the wave lengths differ and we hear the sound faster in one ear than the other because there is a distance difference and so the waves reach one ear slightly faster than the other ear. This small fraction of time difference helps us locate sound and tell where they are coming from. But when the wavelength is as big as our face, then we get confused because whether the sound came from left or right, we heard it in both ears at the same time so we don’t know which way it actually came from.