1. PWV. Waves and Vibrations Benchmark 4 Describe different types of waves and their technological applications.

2. Mechanical Waves depend on some form of matter for their existence. Waves in a slinky, for example (demo) need the slinky to exist. Waves in water need the water to exist. We call this matter the medium of the wave. In addition, the medium determines the speed of the wave. Sound waves can travel through solids, liquids and gasses but go at different speeds in each. Sound travels faster through water than through air; and even faster through steel. Mechanical Wave Examples: Sound (SONAR) UltraSound Waves Seismic Waves (Earth Quakes Waves) As we have seen before, there are tow types of waves: Mechanical and Electromagnetic Key concepts… Types of waves

3. Sonar A ship or a submarine will send out sound waves that bounce off of: The sea floor Rocks Other ships Computers process the reflected sound and give information about: size, distance, speed and composition.

4. http://sln.fi.edu/biosci/TOC.biosci.html Sound Waves are transmitted into the body’s tissue. They reflect differently off different types of tissue (bone, muscle, blood, etc.). The recorded sounds are interpreted by a computer and an image is formed. UltraSound

6. Seismic Waves Seismic Waves are waves from Earth Quakes. They come in two forms: S-Waves http://www.schulphysik.de/suren/Applets/Waves/Twave01/T wave01Applet.html http://www.schulphysik.de/suren/Applets/Waves/Twave01/T wave01Applet.html P-Waves http://www.schulphysik.de/suren/Applets/Waves/Lwave01/L wave01Applet.html http://www.schulphysik.de/suren/Applets/Waves/Lwave01/L wave01Applet.html Scientists use seismic wave detectors called SEISMOGRAPHS to detect these waves and predict EARTHQUAKES and VOLCANIC ERUPTIONS.

8. Electromagnetic Waves DO NOT depend on any medium! Electromagnetic waves are any waves that exist in the Electromagnetic Spectrum. The Electromagnetic Spectrum contains all of the waves that move at the speed of light. As you can see, each wave type has a different wavelength and therefore a different frequency. The larger the wavelength, the lower the frequency.

9. Electromagnetic Waves are used in a variety of technologies in both high and low frequencies.

10. Web Exploration http://www.ndt-ed.org/EducationResources/HighSchool/Sound/ultrasound.htm http://yourmedicalsource.com/library/ultrasound/US_work.html http://www.pbs.org/wgbh/nova/lochness/sonar.html