Science with Rina. Sound Waves. How they are created

Video illustration to Sound Wavelength Calculator. In this video, we are going to look at how sound waves are created. Have you ever wondered how this pretty cardinal sings and how this singing gets from the bird to you? Birds make sound almost as we, humans, do. The only difference is that in birds, the sound is produced by vibrations of the walls of the bird’s vocal organ which is called syrinx and we, humans, use our vocal cords for the same purpose. The vocal cords, which are simply folds of tissue, vibrate when the air passes by them. We can observe these vibrations if we try to make a high-pitched bird call using a piece of grass and blowing air across it. We are making this video in winter; grass is unavailable; therefore, we will use a piece of wax paper instead of grass. The air makes the paper vibrate creating a high-pitch sound, which is similar to sound that some birds make. When the air from the lungs is forced across the vocal cords or a piece of paper, vibrations occur. They create areas of compression and rarefaction (regions where the air is spread out), in other words, longitudinal waves. In longitudinal waves, the particles in the air move parallel to the motion of the wave. They compress in the same direction as they travel. These waves travel from sound sources and transmit the energy of the voice or vibrating paper. Louder sound means more powerful compressions and rarefactions. What is the speed of sound traveling through the air? At 20 °C or 68 °F, the sound is traveling at about 343 meters per second or 1125 feet per second or 1 kilometer per approximately 3 seconds. Picture Credits Vocal Cords: Prejun [CC0], from Wikimedia Commons Avian Cyrinx: TecumsehFitch [CC BY-SA 4.0 (], from Wikimedia Commons Larynx and Nearby Structures: National Cancer Institute (USA) Music from YouTube Free Audio Library “Les Toreadors” from Carmen by Georges Bizet Ersatz Bossa by John Deley and the 41 Players

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