Successfully reported this slideshow.
Upcoming SlideShare
×

# The Doppler Effect

• Full Name
Comment goes here.

Are you sure you want to Yes No
• Be the first to comment

### The Doppler Effect

1. 1. The Doppler Effect Victoria Nguyen LO5
2. 2. Daily life scenario  You’re sitting in the car when suddenly you hear a distant siren from behind you. As the ambulance approaches your car, the sound of its siren gets louder and louder. But once the ambulance passes your car, the sound of its siren gets softer. Why?  Well, its because of the Doppler effect!
3. 3. Doppler effect  The Doppler effect is a phenomenon that states that an approaching source of sound will generate a high frequency and switch to lower frequency as it passes by due to the compression and expansion of the sound waves’ wavelength
4. 4. Scenarios of the Doppler effect 1) If the source and the receiver are both stationary, then the frequencies will remain the same. 2) However, if either the source (S) or the receiver (R) are moving, then the frequency at the receiver end compared to the source will be different. Let’s focus on the receiver’s end:  If both source and receiver are approaching each other = higher freq at R’s end  If both source and receiver are moving apart = lower freq at R’s end This also explains why approaching sirens will sound high pitch while a receding siren will sound low pitch!
5. 5. The Doppler effect equation Now that we know the concept of the Doppler effect, we can actually calculate the frequency at the receiver’s end using this equation! Frequency measured at receiver’s end Velocity of sound traveling in air (~343 m/s) Velocity of source Velocity of receiver Frequency measured at source’s end
6. 6. But what do these signs mean??? No need to panic! These signs just represent different scenarios of the movement of the source and the receiver!
7. 7. An end moving TOWARDS a stationary end When either the source or the receiver is moving TOWARDS the stationary end, use the + sign on top and – sign on the bottom. This makes sense because by doing so, we are increasing the numerator and decreasing the denominator, which will give us a higher R frequency, supporting the Doppler effect.
8. 8. An end moving AWAY from a stationary end However, when either the source or the receiver is moving AWAY from the stationary end, change the – sign at the bottom and change it to a + sign. This makes sense because it will decrease the numerator and increase the denominator, which will result in a lower R frequency, supporting the Doppler effect.
9. 9. Now let’s answer the most important question ever!!  What costume is Sheldon (the character from Big Bang Theory) wearing in this picture?
10. 10. The Doppler effect!
11. 11. Hope you enjoyed this presentation. Now you know what the Doppler effect is about!