14-3-doppler-effect-and-sonic-booms_summary

The Doppler Effect of Sound Waves refers to a change in the perceived pitch of a sound due to the relative motion between the source and the observer. This effect occurs when the distance between the compressions (crests) of the sound waves changes due to motion, causing a change in the wavelength and frequency that the observer hears. In the case of a moving source, the sound waves become closer together as the source approaches the observer and farther apart as it moves away, resulting in an increase or decrease in the perceived frequency respectively. On the other hand, if the observer is moving, the perceived frequency will change as they pass through more or fewer wave crests, depending on whether they are moving toward or away from the source. The formula for calculating the observed frequency (fobs) for a moving source is given by: f\_obs = fs \* (v\_w \+/- vs) / v\_w In this formula, fs is the frequency of sound from a source, vs is the speed of the source along a line joining the source and observer, and vw is the speed of sound. The plus sign is used for motion toward the observer and the minus sign for motion away from the observer. A sonic boom is created when a moving object, such as an aircraft or a space shuttle, approaches or exceeds the speed of sound. The approaching aircraft creates a shock wave as it moves through the air, compressing and rarefying it. When this shock wave reaches the ground, it creates a loud, thunderous sound known as a sonic boom. A sonic boom is a constructive interference of sound created by the superposition of shock waves generated by an object moving faster than sound. It creates a shock wave that propagates at the speed of sound and is heard as a sudden, loud, and long-lasting noise. The sonic boom consists of two waves, one originating from the nose of the aircraft and the other from the tail, creating two separate booms that are often heard separated by the time it would take the aircraft to pass by a point. When the aircraft leaves supersonic speeds, the sonic boom fades away, returning to normal sound levels. Doppler Effect and Sonic Booms Learning Objectives: 1. Students will be able to explain the Doppler effect of sound waves, including examples of motion of the source and observer that produce the effect. 2. Students will be able to use the Doppler shift formula to calculate the frequency shift and speed of an object based on the observed frequency, speed of sound, and object velocity. 3. Students will be able to explain the concept of a sonic boom, describe its cause and characteristics, and understand how it is related to the Doppler effect.