# What are waves? a disturbance that transfers energy from place to place. Classified as either 1. Mechanical- require a medium 2. Electromagnetic- do not.

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What are waves? a disturbance that transfers energy from place to place. Classified as either 1. Mechanical- require a medium 2. Electromagnetic- do not require a medium Light, radio, x-rays, and gamma rays are some examples of e/m waves.

Define medium The material through which a wave travels The material through which a wave travels Ex. Gases (air), liquids (water) and solids (rope)

Mechanical Waves Classified as either A wave that moves a medium in a direction parallel to the Longitudinal: A wave that moves a medium in a direction parallel to the direction in which the wave travels. A wave that moves the medium in a direction perpendicular to the direction in which the wave travels. Transverse: A wave that moves the medium in a direction perpendicular to the direction in which the wave travels.

Longitudinal The part of a longitudinal wave where the particles of the medium are far apart are called rarefactions. The part of a longitudinal wave where the particles of the medium are far apart are called rarefactions. The part of a longitudinal wave where the particles of the medium are close together are called compressions. The part of a longitudinal wave where the particles of the medium are close together are called compressions.

Surface Waves

TRANSVERSE WAVES Transverse Waves are waves in which the particles vibrate perpendicularly to the direction the wave is traveling. Transverse waves are made up of crests and troughs. Water waves, waves on a rope, and electromagnetic waves are examples of transverse waves. http://www.acs.psu.edu/drussell/Demos/waves/wave motion.html http://www.acs.psu.edu/drussell/Demos/waves/wave motion.html

Crests and Troughs of Transverse Waves Transverse waves have alternating high points and low points. The high point of a wave is a crest. The low point of a wave is a trough.

Amplitude Amplitude Wavelength Wavelength Frequency Frequency Speed Speed

Amplitude The amplitude of a wave is the maximum distance that the particles of a medium vibrate from their rest position. A wave with a large amplitude carries more energy than a wave with a small amplitude does.

WAVE SPEED Speed - the speed of a wave is how is Speed - the speed of a wave is how far the wave travels in a given length far the wave travels in a given length of time. of time. the speed at which a wave travels. The speed depends on the medium a wave travels through. Waves usually travel faster in liquids and solids than they do in gases. Speed = wavelength x frequency Speed = wavelength x frequency s = x f

Wave Frequency Frequency - the number of complete Frequency - the number of complete waves that pass a given point in a certain amount of time. Frequency can be found by counting the number of crests or troughs that pass a point each second. Frequency is usually expressed in hertz (Hz). One hertz equals one wave per second. High frequency means more waves per second. Low frequency means fewer waves per second.

WAVELENGTH A wavelength is the distance between any point on a wave to an identical point on the next wave.

Energy in Waves Decreased Energy long wavelength small amplitude low frequency Decreased Energy long wavelength small amplitude low frequency Increased Energy short wavelength short wavelength large amplitude large amplitude high frequency high frequency

Wave Demonstrations http://www.acs.psu.edu/drussell/Demos/waves/w avemotion.html http://www.acs.psu.edu/drussell/Demos/waves/w avemotion.html

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