a reflective surface that curves outward and forms a reduced, upright, virtual image; usually used in combination with other lenses

unit for sound intensity

Material that transmits almost all the light striking it so that objects can be clearly seen through it

amount of energy that flows through a certain area in a specific amount of time

change in pitch or frequency that occurs when a source of a sound is moving relative to the listener

reflective surface that curves inward and can magnify objects or create beams of light

Material that transmits some light but not enough to see objects clearly

Colored material that is used to change the color of other substances

human perception of sound intensity

How high or low a sound seems;

lens that is thicker in the middle than at the edges and can form real or virtual images

type of scattering that occurs when light waves are traveling in one direction and are made to travel in many different direction

reflection of light waves off of a smooth surface.

Sound waves with frequency above 20,000 Hz

Sound waves with a speed greater than that of sound.

Sound waves with a speed less than that of sound.

Sound waves with frequency less than 20 Hz