| A | B |
|---|
| frequency | determines the pitch of a sound |
| vibrations | the rapid back and forth movement of matter |
| amplitude | determines the loudness of a wave |
| sound | a form of energy that travels as waves through the air and some solids and liquids |
| hertz | a unit of frequency measured in cycles per second |
| reflection | the bouncing back or change in direction of a wave after it strikes a barrier or an object-also known as an echo |
| trough | the low point of a sound wave where the lowest air pressure occurs |
| pitch | a measure of the highness or lowness of a sound |
| decibel | the unit used to express loudness |
| waves | the form in which sound energy moves from one place to another |
| sonic boom | a large bang caused by an aircraft flying at or faster than the speed of sound |
| echolocation | the process of using reflected sound waves to find objects. Bats, dolphins, and some other animals use this to find food and avoid danger |
