Saturday, June 07, 2008

Science Lesson

I realize that I shouldn't make fun of her or expose her to embarrassment because she gave me life, blah blah blah, whatever. She had children and raised them in the internet age, she had to expect that something of this sort would happen eventually. So here is what happened in a conversation between my mother and I today.

(First, some backstory. A couple weeks ago we went to the National Art Gallery, and while we were shopping around in the gift store, she came upon a little solar-powered contraption that attached to a window and had a prism dangling from it, so when the sunlight came in, it would turn some internal gears, spinning the prism around, and making rainbows dance all over the room. That device stopped working today, and I could hear little gears trying fruitlessly to turn, so I decided to perform some microsurgery on it and get it working again, to soothe my mother's heartbreak over a lack of spinney rainbows.)

Me (as I'm holding the contraption up to the window, trying to catch some light to see if my work had any effect): No, there's not enough light coming in, I can't tell.

Mom: Do you want me to get a flashlight?

Me: I'm sorry, what?!

Mom: A flashlight.

Me: No. How would a flashlight do me any good?

Mom: Well, I figure light is light.

Me: ...No, Mom. Solar power requires a Sun.

Mom: Are you sure?

Me: Yes.

See, the thing about a flashlight vs. sunlight, is that your standard flashlight is about 3 watts (I googled it), while "the power at noon on the equator is about 1 kW per square meter," leaving room for all sorts of variables to enter in and mess with that figure (I maybe googled that as well, don't judge me). So, while light MAY be light, you know, photons bouncing around, making physicists scratch their heads, because (and they will admit this to you when REALLY pressed) they have NO IDEA what is going on with those little buggers - light may be light, but 3 watts vs. 1,000, or even 500 is kinda a huge difference.

And now you know.



Blogger Corith Malin said...

Well, if it's 1kW per 1 m^2, and the little solar panel is probably only about 18cm X 18cm (about 9"x9"), then the amount of power hitting the solar panel is only about 324W. Which is still much more than the flashlight, but also a lot less than your quoted 1 - 0.5kW.

I always thought the real reason why flashlights were such a poor substitute for sun light in solar power situations is because the average flashlight (not any more, but until about 2 years ago) used an incandescent bulb. Incandescent bulbs cast light that LOOKS like the sun (the slightly orange glow) but the sun actually projects white light (composed of light from the whole light spectrum) whereas incandescent bulbs do not emit some of the spectrum (infra-red comes to mind, which is why the infra-red bulb on your remote control does not look the same as a flashlight bulb and also why a flashlight will never turn on a tv).

Of course this all changes when you're talking about LED flashlights. I'm not sure of the light spectrum they produce.

11:38 AM  
Blogger juxtaposer said...

Exactly. I was all set to say something like, "flashlights don't produce the same light that the Sun does," and then I realized, shoot - maybe they do these days. I'm just not up on my latest flashlight technology. I know I should be, but there are just so many other things to Wikipedia.

3:15 PM  
Anonymous Anonymous said...

Making fun of your Mother? I knew we should have left you in the woods tonight. :)

10:04 PM  

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