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The word ______ is used to describe the material a wave passes through.
If a wave is _________, it means it is not absorbed by a surface but bounced off it.
A ________ is the barrier between two materials.
_________ is another word for boundary.
If something ________, it means it soaked up.
If energy is ___________, it means it is moved.
_______________ waves are transverse waves that transfer energy.
If something is a ______, it means it is empty of all materials.
A _________ wave changes direction when it hits a boundary.
__________ refers to sound waves with a frequency that's too high to be perceived by the human ear.
_______ is the ratio of mass to volume.