Material:
|
One tri-colored diode (can be
purchased from Radio Shack), One grounded plug assembly, and One step-down transformer
(can be purchased from Radio Shack). NOTE: You will need to construct the
demonstrator by connecting the step-down transformer and the diode in series (using the
grounded plug assembly). If you do not have any experience with electricity, do NOT
attempt to construct this on your own!! |
| Directions: |
Plug the completed demonstrator into
a standard wall socket. Turn out the lights and gently spin the assembly (with the diode
at the outer end) in a circle in front of you. |
| Safety Concerns: |
CAUTION!!! This activity involves
the use of A.C. current and some electrical wiring. You should NOT attempt to do this
activity or create the demonstrator unless you have experience with electricity.
This demonstration is using electricity that can be potentially dangerous to the person
demonstrating the concept. DO NOT under any circumstances allow your students to
manipulate or use this demonstrator! |
| Questions: |
What do you notice about the color
of the diode when it is not moving? What do you notice about the color of the diode
when it is moving? What colors do you see as you spin the diode in a circle?
How do can you explain the different colors of the diode? |
| Concepts: |
The diode responds to the
alternating current by turning on and off (each of the three colors) at the same rate as
the current is alternating (60 cycles per second). This is much to fast for our eyes to
see without some help. By moving the diode rapidly (but gently) in a line or circle,
our eyes pick up the light flashes at points along the line or in the circle. What
we are "seeing" is the alternating current flashing in front of us. |
