STANDING WAVES, RESONANCE, BEATS, & DOPPLER EFFECT

1. Nick Cavalieri & Joe Spinelli STANDING WAVES, RESONANCE, BEATS, & DOPPLER EFFECT http://techtv.mit.edu/videos/2964-breaking-glass-with-sound

2. What is a wave? • a disturbance or variation that transfers energy progressively from point to point in a medium and that may take the form of an elastic deformation or of a variation of pressure, electric or magnetic intensity, electric potential, or temperature. • There are many different kinds of waves including Standing Waves

3. Waves

4. Standing Waves • The reflected wave, however, would be traveling in the opposite direction from the initial wave, and would result in a standing wave.

5. Waves in Pro Tools

7. Resonance • increased amplitude of oscillation of a mechanical system when it is subjected to vibration from another source at or near its own natural frequency

8. Example of Resonance • What happens to a wave in a medium, for example a violin string, that is tied at two ends? • Suppose the string has tension given . When the string is plucked, the string will vibrate, and a standing wave will be created in the string.

9. Resonance Video • http://vimeo.com/7695319

10. Beats (Beating) • As waves evolve, they move slightly in and out of phase with each other. The resulting constructive and destructive interference produce a pulsation of amplitude. This pulsation is known as beating. • An example of beating can be found here: • http://www.indiana.edu/~emusic/acoustics/phase.htm

11. Visual Example of Beating

12. Christian Doppler • Proposed the idea of “the Doppler effect” in 1842. • The Doppler effect is the change in frequency of a wave for an observer moving relative to the source of the wave. • An example of this is a police siren. • The sound changes as the vehicle moves farther away.

13. Doppler Effect Visuals

14. Bibliography • http://vimeo.com/7695319 • http://www.indiana.edu/~emusic/acoustics/phase.htm • http://hyperphysics.phy-astr.gsu.edu/hbase/Waves/standw.html

15. Quiz son. • The reflected wave, when traveling in the opposite direction from the initial wave, would result in a _____ • Who Proposed the Doppler Effect? • What is a disturbance or variation that transfers energy progressively from point to point? • increased amplitude of oscillation of a mechanical system is ___________ • As waves evolve, they move slightly in and out of phase with each other. The resulting constructive and destructive interference produce a pulsation of amplitude. This pulsation is known as ________

16. BONUS SON. • WHAT KIND OF BIRD WAS ON THE FIRST SLIDE…..?

17. By: Kathryn Haughney And James Hebert Standing Waves, Resonance Beats, and the Doppler Effect

18. Resonance • Resonance – Building up of energy by adding small amounts of energy in time with the natural frequency of an object If you rock back and forth in a rhythm that matches the natural frequency of a swing, you will build up more and more energy.

19. Resonance Frequency – natural frequency that an object vibrates when disturbed

20. Resonance http://techtv.mit.edu/videos/2964 http://recipes.howstuffworks.com/food-facts/wine/question603.htm

21. Standing Waves • A wave pattern is only produced when one end of something is vibrated at just the right frequency. When the proper frequency is used, the interference of the incident wave and the reflected wave occur in such a manner that there are specific points along the medium which appear to be standing still. Because the observed wave pattern is characterized by points which appear to be standing still, the pattern is often called a standing wave pattern.

22. Nodes • A standing wave pattern is a pattern which results from the interference of two or more waves along the same medium. All standing wave patterns are characterized by positions along the medium which are standing still. • Such positions are referred to as nodal positions or nodes. Nodes occur at locations where two waves interfere such that one wave is displaced upward the same amount that a second wave is displaced downward. This form of interference is known as destructive interference and leads to a point of "no displacement." • A node is a point of nodisplacement.

23. More Nodes!

24. The Doppler Effect • http://www.stmary.ws/highschool/physics/home/animations3/waves/DopplerEffectTrain.html • variation in the observed frequency of a wave when there is relative motion between the source of the wave and the receiver • http://www.stmary.ws/highschool/physics/home/videos/waves/F-18.mpg

25. Which way is the ambulance moving?

26. Doppler Effect!!! • http://www.stmary.ws/highschool/physics/home/review/outsideContent/modernPhysics/DopplerEffect.htm • http://www.stmary.ws/highschool/physics/home/animations3/waves/dopplerMouse.swf • http://www.stmary.ws/highschool/physics/home/animations3/waves/doppler.html

27. Which way is the source of this wave moving?

28. TEST! • Resonance - • Doppler Effect- • Nodes- • Standing waves- • Draw a wave source moving to the left.