PASCO WA-9899 Ripple Tank System User Manual
Page 9
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A b o u t t h e E q u i p m e n t
9
Amplitude Adjustment
The Amplitude knob adjusts the ripple arm amplitude.
As you turn the knob clockwise, the amplitude increases. Turning the knob counter-clock-
wise (right-to-left) decreases the amplitude.
As a general rule, adjust the amplitude in all experiments to get a clear wave patter without
distortions.
Frequency Adjustment
The Frequency knob adjusts the ripple arm frequency.
The Frequency display shows the frequency in 0.1 Hz increments. The range is from 1.0 to
50.0 Hz. When the ripple generator is first turned on, the default frequency is 20.0 Hz, a
good starting frequency for the experiments described later. Turn the knob clockwise to
increase the frequency or counter-clockwise to decrease the frequency.
Phase Switch
The Phase switch at the upper right of the ripple generator changes
the phase of the two rippler arms from zero degrees (‘in phase’) to 180 degrees (‘out of
phase’). The switch can be used while the ripple generator is in operation.
Light Source Control
The Light Source can be used as a strobe or as a steady
source. The controls for the light source consist of a three-position Mode switch for select-
ing ‘STEADY’, ‘OFF’, and ‘STROBE’, and a ‘DELTA’ knob that adjusts the frequency of
the light source when it is in the strobe mode.
DELTA Feature
Normally the frequency of the light source in the strobe mode is
the same as the frequency of the ripple generator. When the frequency of the light source
is 5.0 Hz or more, you can use the ‘DELTA’ knob to increase or decrease the frequency of
the light independently of the frequency of the ripple arms. (When the generator frequency
is less than 5.0 Hz, the ‘DELTA’ knob will not change the light source frequency.) Turn the
‘DELTA’ knob clockwise to increase the light source frequency or counter-clockwise
(right-to-left) to decrease the frequency. Each ‘click’ of the ‘DELTA’ knob changes the
frequency of the light source by 0.8 Hz. The Frequency display on the top of the ripple
generator will show the ‘DELTA’ increment (e.g., 1.0, 2.0, 3.0, 4.0, or 5.0 if the ‘DELTA’
knob is turned clockwise, or -1.0, -2.0, etc., if the knob is turned counter-clockwise) for a
few moments and then change back to show the ripple generator frequency. For example,
if the Frequency display shows ‘20.0’ Hz, and you turn the ‘DELTA’ knob one ‘click’
clockwise, the Frequency display shows ‘1.0’ momentarily, and the light source frequency
becomes 20.8 Hz. Note that the ripple generator will continue to oscillate at 20.0 Hz.
This feature of the light source allows the wave pattern to ‘appear to move’ at a constant,
predictable speed when the light source is in the strobe mode and the light source fre-
quency is slightly higher or lower than the ripple generator frequency.
Frequency
display
DELTA
knob
Mode
switch