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Physical Science CPName: Gizmo - Doppler ShiftDate: 2-12-20Per:2 Vocabulary:Doppler shift, frequency, pitch, sonic boom, sound waves, wavelength Highlight your answers in either GREEN / BLUE / OR YELLOW Prior Knowledge Questions (Do these BEFORE using the Gizmo.)Have you ever heard a siren on a moving ambulance, fire truck, or police car? If so, what happens to the sound as the vehicle passes by? . Gizmo Warm-upThe Doppler Shift Gizmo illustrates why the Doppler shift occurs. The Gizmo shows a vehicle that emits sound wavesand an observer who will hear the sounds. 1.Click the PLAY SAMPLE button (). (Check that the Gizmo’s sound and your computer’s speakers are on.) What do you hear? 2.Click Play() and observe the sound waves emitted from the moving car. Click Pause() and compare the sound waves in front of and behind the car. What do you notice?3.Use the Rulerto measure the wavelength, or the distance between the lines, of the waves in front of and behind the car. (Note: The red circles represent every thousandth wave.) Why do you think the waves in front of the car have a shorter wavelength than the waves behind the Introduction: The pitchof a sound, or how shrill or deep it is, is related to the frequencyof the sound waves. The greater the number of sound waves passing by a point each second is, the higher the frequency and the pitch will be. The unit of frequency is the hertz(Hz). Activity A: The Doppler shift Get the Gizmo ready: ●Click Reset(). ●Check that fsourceis set to 500 Hz and vsoundis set to 340 m/s, close to the actual speed of sound. ●Set vsourceto 0 m/s.