# Waves and Sound

Wave-a disturbance that travels through space and carries energy

Simple harmonic motion-the motion an object experiences when a restoring force is proportional to the displacement from equilibrium

Mechanical wave-a wave that needs a medium to travel

Electromagnetic wave-a wave that does not need a medium to travel

Transverse wave-a wave that travels perpendicular to the medium in which it is traveling

Longitudinal wave-a wave that travels parallel to the medium in which it is traveling

Crest-the highest part of the wave

Trough-the lowest part of the wave

Wavelength-the distance between two adjacent crests of a wave.

Frequency-the number of waves that pass a fixed point per unit time

Amplitude-the height of the wave

Period-the amount of time required for a point on a wave to complete one full cycle

Reflection-occurs when a wave strikes a barrier and bounces off

Refraction-occurs when a wave bends as it moves from one medium into another

Diffraction-occurs when a wave bends as it moves around a barrier or through a slit or edge

Constructive Interference-a superposition of two or more waves that results in the waves adding together to form the resultant wave

Destructive Interference-a superposition of two or more waves that result in the waves subtracting or cancelling to form the resultant wave

Standing waves-form when two waves of the same frequency, wavelength, and amplitude travel in opposite directions and interfere

Compression-the region of a longitudinal wave that is most dense

Rarefaction-the region of a longitudinal wave that is the least dense

Doppler Effect-the change in frequency of a wave as a source approaches or leaves an observer

Intensity-the rate at which energy flows through a unit area of the wave

Decibel-a dimensionless unit that describes the ratio of two intensities of sound

Pitch-a measure of how high or low a sound is perceived to be

Resonance-a phenomenon that occurs when the frequency of a force applied to a system matches the natural frequency of vibration of the system, resulting in a large amplitude of vibration

Fundamental frequency-the lowest frequency of vibration of a standing wave

Harmonic series-a series of frequencies that includes the fundamental frequency and integral multiples of the fundamental frequency

Beats-the periodic variation in the amplitude of a wave

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