Elenco Upgrade Kit SC500 to SC750 - Manual (Page 11)

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OBJECTIVE: To make your own resistors.
You need some more parts to do this experiment, so you’re going to
draw them. Take a pencil (No. 2 lead is best but other types will also
work), SHARPEN IT, and fill in the 4 rectangles you see below. You
will get better results if you place a hard, flat surface between this
page and the rest of this booklet while you are drawing. Press hard
(but don’t rip the paper) and fill in each several times to be sure you
have a thick, even layer of pencil lead and try to avoid going out of
the boundaries.
Actually, your pencils aren’t made out of lead anymore (although we
still call them “lead pencils”). The “lead” in your pencils is really a form
of carbon, the same material that resistors are made of. So the
drawings you just made should act just like the resistors in Snap
Circuits
® .
Build the circuit shown, it is the same basic oscillator circuit you have
been using. Touch the the loose ends of the jumper wires to opposite
ends of the rectangles you drew, you should hear a sound like an
alarm. Note: You may get better electrical contact between the wires
and the drawings if you wet the metal with a few drops of water or
saliva.
Making the drawn resistors longer should increase the resistance
while making them wider should reduce the resistance. So all 4
rectangles should produce the same sound, though you will see
variations due to how thick and evenly you filled in the rectangles, and
exactly where you touch the wires. If your 4 shapes don’t sound
similar then try improving your drawings.
Be sure to wash your hands after this project.
Shapes to be drawn.
Use a SHARP No. 2 pencil, draw on
a hard surface, press hard and fill in
several times for best results.
Project #516 Drawing Resistors