doctorow at July 3rd, 2013 15:23 — #1
Alan sez, "Ann Makosinski, a Canadian girl scientist, describes her Google Science Fair submission: an LED flashlight that runs solely on the heat of the human hand. According to the GSF site she is one of 15 worldwide finalists at this point. The Hollow (Thermoelectric) Flashlight - Google Science Fair (Thanks, Alan!) READ THE REST
bzishi at July 3rd, 2013 16:17 — #2
Let's see: 5mW/cm^2 1.75 m^2 (avg skin area per human) 7 billion = 613 GW. Wikipedia says that the world uses about 2.3 TW. We will need to start conserving energy if we wish to have a Matrix-style future where energy is harvested from our skin.
In any case, this is a smart kid, but a windup device would be more effective. The best you are going to get thermoelectrically from a flashlight handle is ~50 mW, while you can easily get more than a watt from a dynamo that charges into a capacitor or a battery.
daneel at July 3rd, 2013 16:21 — #3
I am sad her name isn't Jamie.
50thomas50 at July 3rd, 2013 16:25 — #4
Cory - why do you differentiate between "girl" and "boy" scientists?
peregrinus_bis at July 3rd, 2013 16:31 — #5
Genius. She's a bright spark. Would it work better (brighter) if a tight-fitting sleeve of the do-wha-diddy fed the power?
cellocgw at July 3rd, 2013 16:57 — #6
What -- nobody posting smart ass remarks about how a TEC-powered flashlight works best with a "hot girl" ?
antinous at July 3rd, 2013 17:56 — #7
What part of quotation marks are you having trouble with?
antinous at July 3rd, 2013 17:57 — #8
So... would this thing just be on for five months here in Palm Springs?
kibrit at July 3rd, 2013 17:58 — #9
Good for her, but this is not science. She is not investigating phenomena through the scientific method.
It's not an invention, either. Thermoelectric lights have been around for a while. https://en.wikipedia.org/wiki/Thermoelectric_effect
Even if no one had thought to combine a thermoelectric cell with a light before, it would still not be an invention, because sticking two already-existing things together is not an invention.
Someone on reddit pointed out that the girl's father is a mechanical engineer, but I'll give her the benefit of the doubt on that.
kibrit at July 3rd, 2013 18:03 — #10
Depends on the delta T of the air. Thermoelectric generators require a temperature differential to work.
ridley_john at July 3rd, 2013 18:34 — #11
Hm, 0.5mw for a usable LED brightness? Every LED I've seen uses a minimum of 20mw. Add 50% efficiency of the upconversion, stepping from 0.5 volts to 2.5 volts and you need 5 2 20mw = 200mw at 0.5 volts.
Ah, after watching the end of the video, I see. She's greatly underdriving the LEDs and they're really, really, really dim.
This also is highly dependent on the ambient air temperature and won't run for long unless there's a breeze.
dragonfrog at July 3rd, 2013 18:38 — #12
Yes, but to get a steady watt from a hand crank, you have to be cranking it the whole time. If your flashlight works acceptably on 50 mW, that's 1 minute cranking for ever 20 of use.
I'll take 0 minutes cranking per infinity minutes of use, myself...
50thomas50 at July 3rd, 2013 21:01 — #13
Ask Cory why he calls her a "girl".
antinous at July 3rd, 2013 21:28 — #14
The entire post, except for "Alan sez" is a quote from someone else.
jardine at July 4th, 2013 01:37 — #15
It probably wouldn't work at all in Palm Springs. If it did, it wouldn't work very long. It's my understanding from a previous article that it would work best in cooler temperatures, but even then it only works for about 20 minutes. By that time, the tube would heat up closer to the temperature of the user's hand and stop generating electricity. Right now at 1:30am, it's 22, feels like 29 here. So it would probably work poorly for a few minutes and then stop.
antinous at July 4th, 2013 01:52 — #16
It's 45° to 50° here every day now, 37ish at midnight.
doctorow at July 8th, 2013 15:23 — #17
This topic was automatically closed after 5 days. New replies are no longer allowed.