Superposition of Waves it is very important

It is very important to study

2. Your first experiment will show what happens
when two waves are occupying the same region of a
medium at the same time.
When this happens the waves interfere with each
other and the combined waves take on a new
shape.
You will learn how to determine that shape.
the material or
substance that
propagates a
disturbance or wave

3. First let’s review the basic
parameters of a transverse wave.

4. Crest
Equilibrium
position
Trough
Wavelength
Amplitude
Transverse Wave

5. Next let’s look at the superposition
of some simple combinations of two
waves.

6. The first addition of waves that will
be described involves two waves that
are in phase.
This is referred to as
constructive interference.
A crest of one wave is
positioned with the
crest of the other
wave. The same can be
said for troughs.

7. This represents the displacement
by the white wave alone.
This represents the displacement
by the orange wave alone.
Since they are both displacements
on the same side of the baseline,
they add together.
Just repeat this step for several
points along the waves.

8. The next addition of waves that will
be described involves two waves that
are out of phase.
This is referred to as
destructive interference.
A crest of one wave is
positioned with a trough
of the other wave.

9. This represents the displacement by the white wave alone.
This represents the displacement by the orange wave alone.
Since the two displacements are on opposite sides of the baseline,
the top one should be considered positive and the bottom one negative.
Just add the positive and negatives together like this.
Repeat this step for several points along the waves.

10. Finally we observe two waves that are
partially in phase.
A similar method of adding the waves
will be demonstrated.

11. By overlaying the constructive interference curve
from a previous slide you can tell that the curve of
this slide is not fully constructive interference.
From the baseline measure to the “white” wave.
Then add this to the “orange” wave. See animation.
Note the white arrow would
be zero in length here.
So zero added to the
“orange” wave would give
Zero white arrows added to
“orange” wave occur at these
other locations.
Continuing on with this
process gives

12. Your worksheet
Read the directions –how many
squares does the wave move each
second?
Notice how many seconds pass on
each graph, especially on the back
side!
You need 3 colors –2 for the
original and 1 for the result.

13. Interference Animation

14. The frequencyof a wave is the number of
waves passing a stationary point per
second. It is sometimes expressed as so
many waves per second, so many cycles per
second, or so many oscillations per seconds
The periodof a wave is the time required
for one vibration. It is also the time for a
wave to travel one wavelength.
Period (T) and frequency (f) are inversely
related.

15. f 1 T  In symbolic form
or

16. For a wave, if the distance traveled is a
wavelength(l), then the time to travel
this distance is the period(T).
Since the average speed is defined as a
distance divided by time then

17. l
T
1
v T
v
l
 orlfv
Thereforef
T
1

Remember that