SOUND AND LIGHT VOCAB QUIZ

Acoustics The study of sound.

Beats A periodic variation in the loudness of sound caused by interference when two tones of slightly different frequencies are sounded together.

Decibel A unit for sound intensity; abbreviated dB.

Dispersion The separation of light into colors arranged according to their frequency, by interaction with a prism or diffraction grating, for example.

Doppler Effect A change in frequency that occurs when a source is moving relative to an observer.

Echolocation A process by which objects are located by emitting sounds and interpreting the sound waves that are reflected from those objects.

Electromagnetic Spectrum The range of electromagnetic waves extending from radio waves to gamma rays.

Electromagnetic Wave A wave created by vibrating electric charges, consists of vibrating electric and magnetic fields, and can travel through a vacuum or through matter.

Forced Vibration The vibration of an object that is made to vibrate by another vibrating object that is nearby. The sounding board in a musical instrument amplifies the sound through forced vibration.

Infrasonic Term applied to sound pitch too low to be heard by the human ear, that is, below 20 hertz.

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

Law of Reflection The angle of incidence for a wave that strikes a surface is equal to the angle of reflection. This is true for both partially and totally reflected waves.

Loudness Human perception of sound volume, depends primarily on intensity.

Music A collection of sounds deliberately used in a regular pattern.

Natural Frequency A frequency at which an elastic object, once energized, will vibrate. Minimum energy is required to continue vibration at that frequency. Also called resonant frequency.

Opaque A material that absorbs or reflects all light and does not transmit any light.

Photon A massless energy-containing particle that electromagnetic waves sometimes behave like; the frequency of the electromagnetic wave increases with the energy of the particle.

Pitch Perception of how high or low a sound is; related to the frequency of the sound waves.

Reflection The bouncing back of a particle or wave that strikes the boundary between two media.

Refraction The bending of a wave by a change in its speed as it travels from one medium to another.

Resonance The process by which an object is made to vibrate by absorbing energy at its natural frequency.

Reverberation Persistence of a sound, as in an echo, due to multiple reflections.

Sonar A system that uses the reflection of sound waves to detect objects underwater.

Sound Quality Result of the differences between sounds having the same pitch and loudness.

Ultrasonic Term applied to sound frequencies above 20,000 hertz, the normal upper limit of human hearing.

Translucent A material that transmits and scatters light so that objects viewed through it appear blurry.

Transparent A material that transmits light without scattering so that objects are clearly visible through it.