1. WAVES

2. What are waves? Have you ever ridden a wave in the ocean? Ocean waves travel on the surface of the water. You can see them and you can feel them. As you swim through the water, you can even make your own waves.

3. TSUNAMI Raging Planet: Tsunami =30 meters high

4. Height increases as depth decreases

5. Despite a lag of up to several hours between the earthquake and the impact of the tsunami, nearly all of the victims were taken completely by surprise. There were no tsunami warning systems in the Indian Ocean to detect tsunamis or to warn the general populace living around the ocean. Tsunami detection is not easy because while a tsunami is in deep water it has little height and a network of sensors is needed to detect it. Setting up the communications infrastructure to issue timely warnings is an even bigger problem, particularly in a relatively poor part of the world.tsunami warning systems

6. WHAT IS A WAVE? A disturbance that transfers energy progressively from point to point in a medium The wave is the disturbance (people jumping up and sitting back down), and it travels around the stadium.

7. Longitudinal Waves Longitudinal sound waves in air behave in much the same way. As the wave passes through, the particles in the air oscillate back and forth about their equilibrium positions but it is the disturbance which travels, not the individual particles in the medium. www.kettering.edu

8. Longitudinal wave

9. Transverse Wave Transverse waves on a string are another example. The string is displaced up and down as the wave travels from left to right, but the string itself does not experience any net motion.

10. The same direction and right angle

11. WATER WAVES

12. WATCH THE CIRCLE Watch the water droplet move in a vertical circle as the wave passes. The droplet moves forward with the wave's crest and backward with the trough.*

13. Parts of a Wave

14. CREST, TROUGHS, AND WAVELENGTHS The crest is the highest point on a wave, while the trough, or valley between two waves, is the lowest point. Wavelength is the horizontal distance, either between the crests or troughs of two consecutive waves.

15. AMPLITUDE

16. WAVELENGTH

17. Wavelength and Amplitude Wavelength is the distance between two peaks of a sound wave. It is related to frequency because the lower the frequency of the wave, the longer the wavelength. Amplitude describes the height of the sound pressure wave or the “loudness” of a sound and is often measured using the decibel (dB) scale.

18. FREQUENCY.Frequency refers to how many waves are made per time interval. This is usually described as how many waves are made per second, or as cycles per second. Unit of measurement= Hertz Hz

19. Wavelength and Frequency

20. Doppler Effect Heard an ambulance go by recently? Remember how the siren's pitch changed as the vehicle raced towards, then away from you? First the pitch became higher, then lower. Originally discovered by the Austrian mathematician and physicist, Christian Doppler (1803-53), this change in pitch results from a shift in the frequency of the sound waves, as illustrated in the following picture.

21. CHRISTIAN DOPPLER As the ambulance approaches, the sound waves from its siren are compressed towards the observer. The intervals between waves diminish, which translates into an increase in frequency or pitch. As the ambulance recedes, the sound waves are stretched relative to the observer, causing the siren's pitch to decrease. By the change in pitch of the siren, you can determine if the ambulance is coming nearer or speeding away. If you could measure the rate of change of pitch, you could also estimate the ambulance's speed.

22. Doppler Effect A listener will hear a higher frequency when the source of sound is moving towards them. An observer would hear a higher pitch as it approaches and a lower pitch as it goes away. Approaching = compressed Leaving= stretched out A passenger on a train or ambulance would not hear the Doppler effect because he and the sound are moving together.

23. http://library.thinkquest.org/19537/j ava/Doppler.html

24. Interference- interaction of two or more waves at one point Constructive Two or more waves add together Crest A + crest B= A + B= 2x Higher amplitude when they meet Once they pass through each other, they are unchanged. They retain the amplitude they had before the meeting. Destructive A crest and a trough destroy each other Crest A + trough B- = 0 Lower amplitude = 0 For a brief moment there is no disturbance ____________________ Once they pass through each other, they are unchanged.

25. WAVE INTERFERENCE http://id.mind.net/~zona/mstm/physics/wav es/interference/constructiveInterference/Int erferenceExplanation2.htmlhttp://id.mind.net/~zona/mstm/physics/wav es/interference/constructiveInterference/Int erferenceExplanation2.html http://www.colorado.edu/physics/2000/sch roedinger/index.htmlhttp://www.colorado.edu/physics/2000/sch roedinger/index.html