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How do waves move?

How do waves move?. Compare solid liquid & gas Solid faster than liquid faster than gas (needs medium) More dense – faster What about light? Fastest in vacuum (no medium) More dense - slower.

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How do waves move?

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  1. How do waves move? • Compare solid liquid & gas • Solid faster than liquid faster than gas (needs medium) • More dense – faster • What about light? • Fastest in vacuum (no medium) • More dense - slower

  2. Sounds that are too high in frequency for humans to hear are called ultrasound. Normally, these sounds are above 20,000 Hz. Sounds that are too low in frequency for humans to hear are called infrasound. Normally, these sounds are below 20 Hz. Sound Wave

  3. Doppler effect • Apparent change in pitch of a sound caused by the motion of object making sound

  4. Infrasound Infrasound is sound with a frequency too low to be heard by the human ear. The study of such sound waves covers sounds beneath the lowest limits of human hearing (20 hertz). Many animals, including whales, elephants, rhinoceros, giraffes, okapi, and alligators, communicate using infrasound.Used in movies to give a feeling of unease; can vibrate your whole body

  5. INTERFERENCE When two or more waves come together, they “superimpose” or add together. The total amplitude is simply the sum (positive & negative!) of all the individual amplitudes. The extremes of what can happen are called constructive interference and destructive interference

  6. What is this called? Constructive interference Destructive interference

  7. What is this called? Destructive interference

  8. Standing Wave waves generated when a series of wave pulses are sent through a medium and then reflected back upon themselves. Nodes – distructive interference Antinodes – constructive interference

  9. Refraction • Occurs as waves move from one medium into another or within a medium, like air, that varies  in density or temperature

  10. Spearfishing

  11. Refraction Incedent ray ϴi ϴi ϴr Emergent ray ϴr

  12. Reflection from Plane Mirror

  13. Problems • v = d / t speed = distance / time The unit for speed (or velocity) (v) is meter/second.The unit for distance (d) is meter.The unit for time (t) is second. v = 331 m/sec + (0.6 m/s/C)  Tspeed of sound in air = 331 m/sec + (0.6)(room temperature)The unit for speed (or velocity) (v) is meter / second. • The unit for room temperature (T) is degrees Celsius. • v = f  • speed = frequency times wavelength • The unit for speed (or velocity) (v) is meter/second. The unit for frequency (f) is Hertz (Hz). • The unit for wavelength () is the meter.

  14. Calculate the speed of sound for the following temperatures. • 0 C (cold day) • 35 C (hot day) • 100C

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