| A | B |
|---|
| absorbed | act of being soaked up; take in without reflection |
| echo | repetition of a sound when sound waves reflect from a distant surface |
| frequency | number of vibrations per second |
| pitch | way a person perceives a sound as high or low |
| reflect | bouncing of a wave off a surface changing its direction |
| ultrasonic | sound waves with frequencies higher than the range of limits of human hearing |
| vibration | back and forth or side to side motion |
| volume | loudness of a sound, determined by the amplitude of a sound wave |
| waves | regular disturbances that carry energy from place to place |
| matter | can be solid, liquid, or gas |
