#Rossing science of sound pdf viewer series#

Frequency is the scientific measure of pitch. Pitch is related to frequency, but they are not exactly the same. The number of vibrations per second is referred to as an objectвЂ™s frequency, measured in Hertz (Hz). Cats can hear even higher pitches than dogs, and porpoises can hear the fastest vibrations of all (up to 150,000 times per second!). The fastest vibration we can hear is 20,000 vibrations per second, which would be a very high-pitched sound. The slowest vibration human ears can hear is 20 vibrationsВ perВ second. For example, we would not be able to hear the slow vibrations that are made by waving our hands in the air. However, the vibrations need to be at a certain speed in order for usВ to hear them. If your ear is within range of suchВ vibrations, you hear the sound. As it is disturbed, each molecule just moves away from a resting pointВ but then eventually returns to it.

#Rossing science of sound pdf viewer series#

As a result, there is a series of molecularВ collisions as the sound wave passes through the air, but the air molecules themselves donвЂ™t travel with the wave. This вЂњchain reactionвЂќВ movement, called sound waves, keeps going until the molecules run out of energy. These molecules bump into the molecules close to them, causing them to vibrate as well.В ThisВ makes them bump into more nearby air molecules. When an object vibrates, it causes movement in surroundingВ air molecules.

Sound is a type of energy made by vibrations.

Understand how our inner ear contributes to hearing.Дescribe what pitch is and how it varies.