WavesWaves

• Traveling Traveling disturbance disturbance that carries that carries energyenergy from from one place to one place to another.another.

• Do Do notnot carry carry matter!matter!

Click here for a wave animation

[http://www.catie.org.uk/facesofscience/images/waves_wavelength.jpg]

WavesWaves

• MediumMedium – The matter that the – The matter that the wave travels through.wave travels through.– This determines the speed of a This determines the speed of a

wave!!!wave!!!

Medium & WavesMedium & Waves

• Mechanical WavesMechanical Waves – these – these require a medium to travel require a medium to travel through.through.

• Example: Sound WavesExample: Sound Waves

Click here for a mechanical wave video

Medium & WavesMedium & Waves

• Electromagnetic WavesElectromagnetic Waves – do – do notnot need a medium to travel need a medium to travel through.through.

[http://www.nasa.gov/centers/langley/images/content/114284main_EM_Spectrum500.jpg]

Shapes of WavesShapes of Waves

• Transverse WavesTransverse Waves• The medium moves at right angles The medium moves at right angles

to the direction of the wave.to the direction of the wave.

[http://library.thinkquest.org/15433/unit5/transv1.gif]

Transverse wave demo

Shapes of WavesShapes of Waves

•Crests or Crests or peaks (high peaks (high points) and points) and troughs (low troughs (low points) are points) are created.created.

[http://imagers.gsfc.nasa.gov/ems/wave_crest.gif]

Shapes of WavesShapes of Waves

• Compressional Compressional WavesWaves

• The medium The medium moves back moves back and forth in the and forth in the same direction same direction as the wave.as the wave.

• Also known as Also known as longitudinal.longitudinal.

[http://ffden-2.phys.uaf.edu/211.fall2000.web.projects/p%20marvin%20and%20r%20gray/longwave.jpg]

Shapes of WavesShapes of Waves

•These have These have compressioncompressions and s and rarefactions.rarefactions.

Click here for compressional demo #1Click here for compressional demo #2

Water WavesWater Waves

• Surface moves Surface moves up and down, up and down, but also but also slightlyslightly back back and forth.and forth.

• Only move Only move “matter” near “matter” near shoreline!shoreline!

Water wave demo

[http://www.seafriends.org.nz/oceano/ocean05.gif]