Real-Life Communication
Ted is fascinated by buttons, switches and cords. He works all day
maintaining electronic systems, but when he comes home, he enjoys tinkering
with and creating electric systems in his garage.
This evening you stop
by Ted's garage for a visit, and he shows you how to create a circuit using
a switch, a bulb and a D cell. (This is what we call a regular battery. Technically,
however, a battery is two cells connected together.)
This is what the
circuit will look like:
(From: Experimenting
with Electricity and Magnetism by Ovid K. Wong, A Venture Book, New York,
1993)
Ted will need to make holders for the bulb, the cell and the
switch before he begins. Here are his instructions:
Cell Holder
Put
a paper clip on either end of the cell. Make sure the clip contacts the ends
of the cell. Tape the paper clips by wrapping masking tape lengthwise around
the cell. Put the cell in the groove of a ruler to stop it from rolling.
Bulb
Holder
Push a thumbtack into a small board. Wrap wire around the
tack, making sure to leave extra wire. Hammer the tack into the board. Use
a clothespin to hold the flashlight bulb above the tack. Hammer a small nail
through the hole in the clothespin and tape the clothespin to the block. Wrap
another wire around the metal base of the bulb and extend the wire from the
bulb.
Switch
Push two thumbtacks into a board. Wrap wire
around one of the tacks. Put a paper clip and the end of another length of
wire under the second tack. When the paper clip is turned, it should touch
the other tack because the paper clip is the bridge that will turn the circuit
on or off. Hammer the tacks into the board.
Ted has completed the circuit,
and you watch as the light bulb flashes on and off. "How did he do that?"
you wonder.
You can either try this experiment at home to answer the
following questions, or use the diagram and explanation:
Questions
- What is the key factor to consider when putting the bulb, the cell and
the switch together to create a circuit?
- Connect the paper clip of the D cell to one end of the wire of the bulb
holder. Connect the second end of the wire from the bulb holder to one wire
of the switch. Connect the second wire of the switch to the other clip on
the D cell. Do you have a complete circuit? Why or why not?
- Turn the paper clip to bridge the two thumbtacks. Is the circuit open
or closed? How can you tell?
- At home in your garage, you recreate Ted's circuit. You're intrigued and
want to take the experiment a step further. You want to know what materials
are insulators (won't conduct electricity) and which are conductors (materials
that will conduct electricity).
These are the materials you use in your circuit:
- Paper clip
- Eraser
- Paper
- Glass
You place each object between a contact point in the circuit.
Which
materials are conductors? How can you tell?
Want to learn more? Check
out this URL:
Online Tutorial
Internethttp://www.electronics-tutorials.com/