Using a variety of models, she demonstrates how the melanin pigment in both hair and skin react to light energy, producing the different color changes. This week's technological flops include a gasoline powered commuter scooter and a self guided car. She describes some of the features of this unusual animal and explains that unlike most rodents, cavies are large enough to be hunted for food by the local natives. Anytime something vibrates, it makes a sound. The pitch of the sound produced by a vibrating object depends on its frequency, or speed of vibration.
Frequency is a measure of how many sound waves pass a given point in a second.
When you blow into a tuba it produces a low pitch sound because it vibrates the air slowly. In other words, its frequency is low. If you were to blow into a piccolo instead, you would get a very high pitched sound because there are many more vibrations each second, so the frequency is high. Generally, speaking, the longer the vibrating column of air, the lower the frequency and pitch of the sound. You may have noticed that when you listen to the stereo, every once in a while, the windows in the room buzz.