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Science - Coggle Diagram
Science
Waves
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Sound waves
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Hard surfaces reflect sound well, so it makes an echo.
Soft surfaces, like curtains and carpets, reflect very little sound. They absorb sound instead, resulting in no echoes.
Pressure waves
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Sound with a frequency more than 20,000 Hz is called an ultra sound
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Ultrasound has many applications in medicine, including ultrasound scans to check on the health of unborn babies.
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Detecting sounds
Microphones
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These devices contain a diaphragm, which does a similar job to the eardrum.
The vibrations in the air make the diaphragm vibrate, and these vibrations are changed to electrical pulses.
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An ear has an eardum inside, connected to three small bones.
The vibrations in the air make the eardrum vibrate, and these vibrations are passed through the three small bones to the cochlea.
Signals are passed from the cochlea to the brain through the auditory nerve, and our brain interprets these signals to sound.
Sound frequency (pitch) is measured in hertz, and humans have an auditory range from 20 Hz to 20,000 Hz.
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