| Term | Definition |
| Waves | a disturbance that moves through matter or space. |
| Transverse Wave | causes particles in matter to move back and forth at right angles to the direction in which the wave travels |
| Compressional Wave | causes particles in matter to move back and forth along the same direction in which the wave travels |
| Wavelength | the nearest point moving with the same speed and direction |
| Frequency | is the number of wavelengths that pass by a point each second |
| Law of Reflection | the angle that the incoming wave makes with the normal equals the angle that the outgoing wave makes with the normal |
| Refraction | is the change in direction of a wave when it changes speed as is it travels from one material to another |
| Diffraction | bending of waves around an object |
| Opaque | Not being able to see through |
| Translucent | Allowing some light through but not detailed images |
| Transparent | Allowing light to pass through, objects can be directly seen |
| Reflect | A throw back without absorbing it |
| Absorb | To take in or absorb by chemical or physical action |
| Transmit | to cause something to pass on from one place or person to another |
| Loudness | Loudness is the way in which we perceive amplitude |
| Pitch | the quality of a sound governed by the rate of vibrations producing it; the degree of highness or lowness of a tone. |
| Echo location | the location of objects by reflected sound, in particular that used by animals such as dolphins and bats |
| Echo | a sound or series of sounds caused by the reflection of sound waves from a surface back to the listener |
| Doppler Affect | increase of sound or frequency |
