Doppler Effect Flashcards
(8 cards)
Consider the diagram below with a fire truck with the sirens on that is NOT MOVING and person standing some distance away, who is also not moving.
What do the green circles in this diagram represent? What do they show?
The green circles represent the wave fronts from the siren’s sound waves.
They show the person is hearing the same frequency as the sound when it was emitted from the truck. (The waves are the same everywhere).
When an emergency vehicle with its siren blaring drives by, the tone that you hear changes in pitch as it travels along. What is this effect called?
Doppler shift
True or Fale: The Doppler shift is associated with ALL waves types.
True
Consider the diagram below with a fire truck with the sirens on that IS MOVING and person standing some distance away, who is also not moving.
What do the green circles represent? What do they show. What will the person hear?
The green circles represent the wave fronts being emitted from the fire truck.
They show that the sound waves are BUNCHING UP as the firetruck catches up with its own sound waves.
The person in this diagram will perceive an INCREASED FREQUENCY (higher tone) than the sound emitted from the truck.
What if someone was standing on the other side of this diagram? What would they hear? Why?
If the observer was instead standing behind the fire truck and it was moving away from the observer, then the sound waves would be hitting the observers eardrums at a decreased frequency and the observer would hear a lower tone.
When the frequency of sound wave changes, what do we hear?
We hear a change in PITCH
Each musical note represents a specific pitch, with higher notes having higher frequencies and lower notes having lower frequencies
When the frequency of a sound wave decreases, what happens to the pitch?
It decreases
What happens to the frequency of a sound wave when the pitch increases?
The frequency increases
