What is a Wave?What is a Wave?Sound and Light are forms of energy that travel in Sound and Light are forms of energy that travel in waveswaves

A A wavewave is a repeating disturbance or movement that is a repeating disturbance or movement that transfers energy through matter or spacetransfers energy through matter or space

All waves are produced by something that vibratesAll waves are produced by something that vibrates

Waves carry and transfer energy from one place to Waves carry and transfer energy from one place to anotheranother

Some waves need a medium to travel through, while Some waves need a medium to travel through, while others can move through others can move through empty space, known as a empty space, known as a vacuumvacuum..

A A mediummedium is a material through which a wave travels is a material through which a wave travels (solid, liquid, or gas)(solid, liquid, or gas)

Types of WavesTypes of WavesMechanical WavesMechanical Waves are waves that travel only are waves that travel only through matterthrough matter– TransverseTransverse wave wave – – a wave in which particles of the medium a wave in which particles of the medium

move up and down at right anglesmove up and down at right angles to the direction that the to the direction that the wave travels wave travels

Ex. Water wavesEx. Water waves– Compressional Compressional wavewave – – a wave in which particles of the a wave in which particles of the

medium medium move back and forthmove back and forth in the direction of the wave in the direction of the wave motion in the same direction that the wave travelsmotion in the same direction that the wave travels

In this wave, the particles compress and then spread In this wave, the particles compress and then spread apart as a way to pass on energy (also called longitudinal apart as a way to pass on energy (also called longitudinal waves)waves)Examples : Sound waves, slinkiesExamples : Sound waves, slinkies

Electromagnetic WavesElectromagnetic Waves – are waves made by vibrating – are waves made by vibrating electric charges and can travel through spaceelectric charges and can travel through space

Examples: Visible light, radio waves, UV rays, InfraredExamples: Visible light, radio waves, UV rays, Infrared

Mechanical WavesMechanical WavesCompressional Wave Transverse Wave

Compression – part of a medium where particles are close togetherRarefaction –part of a medium where particles are far apart

Electromagnetic WavesElectromagnetic Waves

The electric field is perpendicular to the magnetic field

Parts of a WaveParts of a Wave

Crest

Wavelength

WavelengthTrough

Normal Rest Position

Frequency = 2 waves per second

What are the parts of the wave?What are the parts of the wave?CrestCrest – – highesthighest point of a wave point of a waveTroughTrough - - lowestlowest point of a wave point of a waveWavelengthWavelength – the distance between – the distance between two creststwo crests or or two two troughstroughsFrequencyFrequency – how many – how many wavelengthswavelengths pass a fixed pass a fixed point each secondpoint each second– Expressed in Hertz (Hz)Expressed in Hertz (Hz)– As frequency increases, wavelength decreasesAs frequency increases, wavelength decreases

Amplitude Amplitude – h– heighteight of a wave, or the amount of of a wave, or the amount of energy energy in a wavein a waveRest position (equilibrium) –Rest position (equilibrium) – describes a wave at describes a wave at restrest, , not passing on energynot passing on energyhttp://www.ngsir.netfirms.com/englishhtm/TwaveA.htmhttp://www.ngsir.netfirms.com/englishhtm/TwaveA.htm

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