1. What is it?

2. the __________ of the pulse
E. The Doppler Effect
A bug jumps
once on a pond,
creating a pulse.
(top view)
bug
_____________ :
 all points drawn are
the __________ of the pulse
all points have ___________________________
the shape is __________________
wavefront
peak
the same phase
a circle

3. l l A bug jumps at a ___________, constant f creating waves. side view
newest wavefront
A bug jumps
at a ___________,
creating waves. v
constant f l
bug
side view
of waves l
oldest wavefront
What would a diagram of the troughs look like?
perpendicular
The wave v's are ______________________ to the wavefronts.

4. spheres
In 3-dimensions, the wavefronts are _________________.

5. Far away from the wave source, the wavefronts become
_________________ and more like _________________.
less spherical
plane waves
wavefronts = surfaces
with ____________________
wave source
equal phase
spherical waves
nearly plane waves
Far away, the wave velocity vectors become ____________
parallel

6. Now bug moves left while jumping at a constant frequency l shorter l
higher 4 3 2 1
_________ l
_________ f
longer
lower
old wavefront is
__________________
newer wavefront
_________________
centered on 1
centered on 2

7. It doesn't matter whether the source is moving…
observer:
Observer measures:
wave source: v
_________ l
_________ f
shorter
v =0
higher v
_________ l
_________ f
longer
v =0
lower
…or if the observer is moving with the source at rest:
Observer measures:
v =0 v
_________ l
_________ f
shorter
higher
v =0 v
_________ l
_________ f
longer
lower

8. The Doppler Effect – a shift in the ____________________
of a wave caused by _________________________between a
____________ and __________________.
observed frequency
relative motion
source
an observer
1. Is true ______________________________ waves.
for sound, light, water, etc.
2. The __________ f of the source ______________________ .
actual
does NOT change
3. The f is ____________ and the l is ___________ if the
distance between observer and source is ____________
and ______________________ .
higher
shorter
decreasing
vice versa
The speed of the wave itself is _____________________
________________________ .
the same on both
sides of the source

9. 5. If a sound source is approaching you, you will
hear a sound with a __________________________ .
If it is receding from you, you will hear a sound that
is _________________ .
higher pitch
lower in pitch
6. __________ light has a shorter l than ________ light.
Light sources that are approaching an observer will
have ____________ l and _____________ f . This is called
a __________ shift.
Light sources that are receding from an observer
will have ____________ l and _____________ f. This is
called a __________ shift.
Blue
red
shorter
higher
blue
longer
lower
red
7. The faster the speed of the source or the observer, the _______the shift in l and f.
more

11. Applications of the Doppler Effect:
1. radar: return time  ______________________
Doppler radar  ______________________
 ______________________
2. measure ____________________________ speeds
3. monitor _________________________
4. aid in diagnosis of ____________________________
5. red shift/blue shift of _____________________
6. measuring rotation of _______________________
7. ______________________________________________
distance to storm
speed of storm
approaching or receding
car or baseball
blood flow
deep-vein thrombosis
galaxies
the Sun or a galaxy
motion detectors—security systems

12. receding from
Earth  red
shifted
approaching
Earth  blue
shifted

13. at rest with respect to Earth
red shifted  galaxy is moving
away (receding)

15. Using the Doppler
Effect, Hubble found
that the farther a
galaxy was, the faster
it was moving.
A modern
Hubble Diagram:

16. Stationary Sound Source

17. Source moving with vsource < vsound
( Mach 0.7 )

18. Source moving with vsource = vsound
( Mach 1 - breaking the sound barrier )

19. Source moving with vsource > vsound
(Mach supersonic)

21. Sonic booms – occur when _____________________
exceeds the ________________________ in the medium.
The wavefronts _______________ in a _________________
that is dragged behind the ________________________ .
The wavefronts _____________________ to produce a
large ________________________________________.
The same thing happens when a ____________ travels
faster than the speed of _____________________ and
leaves behind a _______________________ .
speed of a source
speed of waves
pile up
cone shape
wave source
add together
amplitude shock wave
boat
water waves
large wake