·Are repeating disturbances or vibrations that transfers or moves energy from place to place. Waves:

·Are created when a source of energy causes a vibration. http://www.dynamicmarching.com/custom/waves.jpg

·Carry energy, but NOT matter. http://millertalbot.files.wordpress.com/2009/07/waves.jpg

Two types of waves longitudinal transverse

LONGITUDINAL WAVES

TRANSVERSE WAVES

by Dr. Michael R. Gallis Penn State Schuylkill click for movie

·Example: sound waves, springs ·a wave in which the particles move parallel to the path of the wave -also called compressional waves ·Example: sound waves, springs longitudinal wave

·When the particles are squished together it is called a compression ·When the particles are spread apart it is called a rarefaction Compression wave parts

PARTS OF A LONGITUDINAL WAVE compression rarefaction wavelength

·particles vibrate with an up-and-down motion. ·Transverse means “moving across” ·The particles move perpendicular to the direction the wave is traveling ·Example: ·Ocean Wave ·Radio Wave Transverse

Transverse Wave Parts ·Crest- top peak ·Trough- bottom ·Wavelength- distance from crest to crest (or trough to trough) ·Amplitude-distance from center line to crest (or trough) crest wavelength amplitude trough

PARTS OF A TRANSVERSE WAVE amplitude crest trough wavelength

·A medium is a material through which waves travel – it can be a solid, liquid, or gas.

Waves are classified as: Mechanical Electromagnetic ·Need to travel through a medium to vibrate in order for energy to be transferred. ·Can be transverse or compressional. ·Examples: sound waves, water, and seismic. ·Can travel through a medium or empty space. ·Are transverse waves only ·Examples: radio waves, microwaves, infrared rays, visible light, ultraviolet waves, and x-rays.

http://blogs.edf.org/climate411/wp-content/files/2007/07/ElectromagneticSpectrum.png

Click on the picture for a short video Electromagnetic spectrum http://www.empiricaltruth.com/discovery/images/ElectromagnaticSpectrum.jpg

Draw a Venn diagram for electromagnetic and mechanical waves.

Properties of Waves ·Frequency · is the number of waves that occur in a given amount of time ·1 wave is measured by 1 wavelength ·Measured in hertz (Hz) ·Higher frequency = more energy

·A higher frequency causes a shorter wavelength and has greater energy. ·A lower frequency has a longer wavelength and has less energy.

Properties of Waves · is the height of a wave ·Amplitude ·Larger amplitude = more energy

Properties of Waves · is the distance between crests or troughs ·In longitudinal waves it is between adjacent compressions or rarefactions ·Wavelength

Wavelength: ·The measure of the distance from crest to crest in a transverse wave.

·measure from rarefaction to rarefaction in a compression wave. wavelength http://images.google.com/imgres?imgurl=http://www.science-class.net/Notes/Images_8th_Notes/Transverse-Wave.png&imgrefurl=http://hassosan.seesaa.net/article/139646418.html&usg=__zavOGdWf6-vsqajJOB35XifeofU=&h=306&w=515&sz=52&hl=en&start=1&itbs=1&tbnid=a1QgZvu1L4meDM:&tbnh=78&tbnw=131&prev=/images%3Fq%3Dmechanical%2Bwaves%26hl%3Den%26gbv%3D2%26ndsp%3D18%26tbs%3Disch:1

Properties of Waves ·Wave speed · is the speed that a wave travels (distance a wave travels divided by time) ·Depends on the medium the wave is traveling through · v = λ X f (v is velocity, λ is wavelength, f is frequency)

http://liology. files. wordpress http://liology.files.wordpress.com/2009/12/waves-patterns-in-space-and-time.jpg ·In a transverse wave, the greater the amplitude, the more energy it has.

·Sound waves with greater amplitudes will be louder. http://stevegarufi.com/manitoucliffdwellings8.jpg

·Light waves with greater amplitude will be brighter.

http://www.lcse.umn.edu/specs/labs/images/sound_tran_long.gif

compression compression wave wavelength transverse wave wavelength rarefaction amplitude crest trough

Write the formula for wave speed:

1) A wave with a frequency of 500 hz has a speed of 200 m/s 1) A wave with a frequency of 500 hz has a speed of 200 m/s. What is the wavelength? 2) A radio wave with a wavelength of 100 m has a frequency of 500 hz. What is its speed?

http://www. science-class. net/Notes/Images_8th_Notes/Transverse-Wave http://www.science-class.net/Notes/Images_8th_Notes/Transverse-Wave.png

http://missionscience.nasa.gov/ems/index.html good web sit for NASA EM site