Unit 7, the white noise machine. And now, ladies and gentlemen, the moment you have all been waiting for. Here's the winner of this year's science contest, Charles Moore. Charles, tell everyone about your invention. Thank you. For the science contest this year, I've invented a white noise machine. Let me explain what that is. Have you ever been kept awake at night because of the sound of traffic or people talking or loud music? These types of noise are sometimes called dark noise. Dark noise is made up of sounds that bother you so much that you can't concentrate on what you are doing. White noise is not exactly noise. In fact, white noise can't be heard at all. White noise is made up of invisible waves of sound that reduce the effects of dark noise by making sounds of the opposite frequency. It's like being in the ocean and seeing a large wave coming toward you. It might knock you down. But if you could send a wave or many small waves toward the big wave, it wouldn't be as powerful because the small waves would hit it and reduce its size. My machine does this with sound. As a sound enters the microphone, the machine determines the sound's frequency. Then it makes a sound in the opposite frequency that cancels out the first sound. I hope my machine will give some peace and quiet to people living in noisy places. Thank you.