Internet Version [Naruhodo no Mori] Vol.24
by Yumiko Mori
Vol. 24 December 15th, 1996
Toshi: "Look! Infra-red light comes out from here."
Mom: "You can not see where infrared light comes out by your eye.
But I heard you can see it through a video camera."
Toshi: " I want to learn how different channels send different signals."
Mom: "You remember Satoshi aimed the control to wall and changed channel?
I wonder if infra-red light can be reflected at wall."
Toshi: "I think infra-red light can reflect just like regular light."
Mom: "You know black colored surface can absorb light.
Do you think infra-red can be absorbed by black?"
Toshi: "How about trying an experiment?"
Mom: "We can try all sorts of things."
Mom places different color papers, books, mirrors, cloths,
and even trash bags.
Mom: "Shall we start?"
Satoshi: "I am using this remote control, Mom!"
Mom: "Satoshi, can I borrow your control?"
As known when rainbows occur, sun light can be separated into violet, blue, green, yellow, and red colors. This is because each color has a different wave length, red being the longest. Infra-red light has its wave length slightly longer than red light. Its invisible but it is safe for human eyes because its light energy is small. (In contrast ultra-violet has very large energy and is harmful to human eyes.) Infra-red light is also used as sensors.
Prank #1 | ||
| Aim your remote control at many different directions and try to change channel | ||
| -- | Find what can reflect infrared light Try wall, windows, or ceiling. | |
| Do right in the front of the light detector
on the TV front panel. | ||
| Place an object between the control
and the light detector. | ||
| -- | Infra-red light can go through plastic or paper. But it does not go through black plastic or paper. | |
Prank #2 | ||
| Aim the control at someone's eye who is watching TV | ||
| -- | Eye is basically a lens. You should be able to succeed. | |
Prank #3 | ||
| Remote control of a remote control using a mirror | ||
| -- | If you can adjust the mirror angle well,
you can reflect the light toward the target. The reflector doesn't have to be a mirror, as long as its surface is flat. (except transparent and black colored one) | |
Prank #4 | ||
| Take a video record of the front face of a remote control using a camera. | ||
| -- | You can find infra-red light is coming out from the front face of the control. | |
Our family likes watching TV, so we are using our remote control many times a day. As we played with the control time to time, I started to appreciate how clever this invention was. I wonder how the inventor came up with this clever idea. There are so many useful things around us that we can not really appreciate amazing technology. I have participated an education forum called 'Internet robot contest'. From that experience for the first time I realized there is a big gap between what you think is possible and what you can actually invent. I think the progress of technology is the result from many repeats of trial and error. When I finished my robot construction and saw how it moved as I had expected, I was so ecstatic. I guess engineers who invented remote controls would have felt as ecstatic as I was. Many technological advance is brought by efforts of these engineers. Thank you, those engineers!
| Author | Yumiko Mori (Zushi, Kanagawa, Japan) |
|---|---|
| Illustration | Mitsue Ogata |
| Translator | Akira Ishihara |
| HTML format | Muneo Kume |
