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Comment Re:Space - application with today's Superconductor (Score 1) 71

Common sense: FAIL

The two sides (in and out) of your can are only at a few hundred Kelvin, and the rate of IR leaving one side for the other is very low (and being only a few Kelvin apart, the net rate is going to be even lower). The sun, however, is at a few million Kelvin, and thus sends out IR at a much higher rate.

Perhaps you're thinking of the inner core where fusion takes place. The surface, which is what radiates heat, light and other things to Earth, is not nearly as hot. One online figure is 5777k:
http://en.wikipedia.org/wiki/Sun

The rest of your point is still valid, radiation isn't nearly as effective at moving heat as are conduction and convection, and that's why a Thermos bottle works.

Comment That's a HUGE instantaneous charge. (Score 1) 348

Okay, so it's ten seconds, not instantaneous, but the power is huge. Another aspect of such high charge rates is the "gas station" needs to be an electrical substation. The standard US house service is 240V, 200A (48KW), which will take about an hour to put a 50KWH charge into the battery, and that's if there's nothing else taking power in the house.

I'll leave the calculation of the power required to put 50KWH into a battery in ten seconds as an exercise for the reader, but it's big. I wouldn't want to be closer than maybe a kilometer if something "goes wrong."

Comment Usenet thread and hobby robot clubs (Score 1) 136

Here's a recent thread on the Usenet newsgroup comp.robotics.misc - the poster asks about how to do a high school club, but (especially with other posts here about how smart kids are) many responses should apply to your situation:

http://groups.google.com/group/comp.robotics.misc/browse_thread/thread/775ceae020f351a6#

I hadn't heard of the TI calculator interface before, and I've been to the monthly Atlanta meeting for years. Lately we've been wowed by one member's 3PI line follower (video on the site below).

And while the following isn't what you asked, it will make a good complement, and you're bound to find others there from your area with school-related activities similar to yours who can help. There may already be a general hobby robot club in your city that welcomes "children of all ages." Google for these:

robot clob
hobby robot

with the name of the nearest major city.

There's certainly a club in Atlanta:
http://botlanta.org/

Be sure to check out the Links page, at the bottom are links to other robot clubs in the USA (there may be other clubs not listed).

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