Elenco Circuit Maker Sound Plus 200 - Manual (Page 55)

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Project #126 Sound Wave Magic
Paper tray
Salt
Sample Cut-out Pattern
(fold)
(fold)
(fold) (fold)
Project 128
Photo Pitch
Project #127 Pitch
Replace the 5.1KW resistor (R3) with the
photoresistor (RP). Wave your hand up
and down over the photoresistor to
change the sound. Changing the light on
the photoresistor changes the circuit
resistance just like varying the adjustable
resistance does. Note: If you have the
adjustable resistor (RV) set to the right
and light shining on the photoresistor,
then you may not get any sound because
the total resistance is too low for the
circuit to operate.
Build the circuit on the left,
turn it on, and vary the
adjustable resistor (RV). The
frequency or pitch of the
sound is changed. Pitch is
the musical profession’s
word for frequency. If you’ve
had music lessons, you may
remember the music scale
using chords such as A3, F5,
and D2 to express the pitch
of a sound. Electronics
prefers the term frequency,
as in when you adjust the
frequency on your radio.
Build the circuit shown on the left and connect the
speaker (SP2) using the two (2) jumper wires. Then,
lay the speaker on a flat hard surface.
Setup: Use some paper and scissors to cut out a
rectangular pattern. Use the one shown below as a
guide. Use colored paper if available. Fold at the
points shown. Scotch tape the corners so the tray has
no cracks at the corners. Place the tray over the
speaker and sprinkle a small amount of white table salt
in the tray. There should be enough salt to cover the
bottom with a little space between each salt grain.
Sound Magic: Turn on the circuit by turning on the
slide switch (S1). Adjust the adjustable resistor (RV)
for different pitches and watch the salt particles.
Particles that bounce high are directly over the
vibrating paper and ones that do not move are in the
nodes where the paper is not vibrating. Eventually, all
the salt will move to the areas that have no vibration,
and stay there.
Change the position of the tray and the material used
to create different patterns due to the sound. Try sugar
and coffee creamer, for example, to see if they move
differently due to the sound waves.
CM-200_Manual_031914.qxp_CM-200_Manual_031914 4/2/14 12:04 PM Page 55