Material:
|
A. Old CD disks (Ron picks up a couple of hundred each month from local radio stations)
B. Propane torch
C. Pliers
D. Pennies
E. Spinner Patterns from PDF download
|
| Directions: |
1. Download the spinner patterns and make copies that fit a CD diameter.
(I think it takes a reproduction of about 110%.)
2. Next cut out the circle patterns. (I use a circle cutter found at an
Art Store.)
3. Spray the back side of the patterns with spray glue, such as 3M.
4. After the patterns are in place, you are ready to place the penny in
the middle opening.
5. Hold a penny with needle nose pliers over an open flame until hot enough
to slowly melt into the center of the CD.
6. Position the hot penny almost half way into the hole and then place
the CD over an open cup or drinking glass to cool.
7. The penny will allow you to spin the CD. You may wish to put patterns
on both sides for multiple use.
8. The pie shaped pattern such be spun under fluorescent light. The pattern
will appear to stop and reverse as the spinning frequency matches the
bulb output.
|
| Safety Concerns: |
The pennies are VERY hot and can
even melt if you over heat. If you get the penny too hot, it will melt right
through the plastic and not remain in an upright position. |
| Questions: |
1. What colors do you see when the CD is spinning?
2. What explanations can you offer for these colors?
3. Why do the pie shaped spinning patterns look different under sunlight
or incandescent light, compared to florescent?
4. What part of this is due to physics and what might biology have to
do with your observations?
|
| Concepts: |
Light frequencies
Human eye physiology
AC current
|
