Frequency is measured in .......

A sound is produced when a substance vibrates. As a signal perceived by one of the major senses, sound is used by many species for detecting danger, navigation, predation and communication. The energy from the vibration travels in waves - when these waves travel to your ears and then to your brain, you hear the sound. When someone plays a guitar, you can see the vibrating strings and hear the sounds they produce - low, medium and high pitch. It's not just air that can carry sound waves - in fact, solids are the best medium for transmitting sound and liquids are also better at it than air is.... Show more

A sound is produced when a substance vibrates. As a signal perceived by one of the major senses, sound is used by many species for detecting danger, navigation, predation and communication. The energy from the vibration travels in waves - when these waves travel to your ears and then to your brain, you hear the sound. When someone plays a guitar, you can see the vibrating strings and hear the sounds they produce - low, medium and high pitch. It's not just air that can carry sound waves - in fact, solids are the best medium for transmitting sound and liquids are also better at it than air is. Sound can also bounce off solids - when this happens we hear an echo. An echo is a reflection of a sound wave.

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