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Drag the items on the right into the middle to match with the items on the left.
echo 
decibels
vibration
ear
hertz
Hz
sound generator
oscilloscope
microphone
vacuum
gas, liquid, solid
sound reflecting off a hard surface
scale of loudness
sound travels in this form
this detects sound
one vibration per second
shorthand for a Hertz
machine that produces sound
machine that shows sound waves
machine that collects sound
sound cannot travel through this
sound travels through this

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