PASCO WA-9899 Ripple Tank System - Manual (Page 23)

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M o d e l N o . W A - 9 8 9 9 E x p e r i m e n t 4 : I n t e r f e r e n c e
23
Question
1. How does the pattern of interference from two point sources compare to the pat-
tern of interference from the two slits?
Extensions
Three Point Sources Raise the ripple generator, remove the two standard dip-
pers, and attach the plane wave dipper to the ripple arms. Put three standard dippers
into the clips on the plane wave dipper so that the three dippers are evenly spaced.
Adjust the ripple generator so that the three standard dippers barely touch the surface
of the water.
Set the ripple generator frequency to 20 Hz, and repeat the procedure as you did for
two point sources. Adjust the amplitude as needed to make a clear pattern.
Sketch the wave pattern formed as the wave fronts from the three point sources inter-
fere with each other.
Five Point Sources Put two more standard dippers
into the clips on the plane wave dipper so that all five dip-
pers are evenly spaced (see Figure 4.4). Repeat the proce-
dure as for three point sources.
Sketch the wave pattern formed as the wave fronts from
the five point sources interfere with each other.
Actuators Raise the ripple generator and remove the
plane wave dipper. Attach a dipper adapter to each of the
two small actuators, and put the dipper adapters into the
clips on the ripple arms (see Figure 4.5). Adjust the ripple generator so that the two
small actuators barely touch the surface of the water. Repeat the procedure as for the
two point sources. Adjust the amplitude as needed to make a clear pattern.
Sketch the wave pattern formed as the wave fronts from
the two small actuators interfere with each other.
Replace the two small actuators with the two large actua-
tors and repeat the procedure.
Figure 4.4: Multiple Dippers
Figure 4.5: Small Actuators