What is Digg?Warning: The Content in this Article May be Inaccurate
Readers have reported that this story contains information that may not be accurate.469 Comments
- IanCal, on 02/21/2008, -39/+347Genuis? The guy can't even do basic physics.
This thing has a 23kg weight, falling 4ft, which gives an output of 270J, assuming 100% efficiency (!)
270J is 1W for just over 4 minutes. One watt for 600 lumens is also really, really generous. The best are in the region of 150 lumens/watt.
"lasts 200 years" means the materials will last that long. Even using their calculations you have to lift a 23kg weight 4 ft every 4 hours. - Falldog, on 02/21/2008, -4/+233To be fair the submission description makes it sound like the light will last for 200 years.
- kevir, on 02/21/2008, -4/+169I don't think you understand the gravity of the situation.
- zKman, on 02/21/2008, -5/+139Let's look at the claims of light output. It says for 4 hours, this thing will output 600-800 lumens. White LEDs have a luminous efficacy of 10-90 lum/W. Let's assume 600 lumen output at 70 lum/W efficacy. So, the power required for this stated output is:
600 lum/(70 lum/W)=8.5 Watts
This seems to correspond to LED bulbs with similar light output. http://www.treehugger.com/files/2007/02/led_bulb_r ...
8.5 watts over 4 hours is 120000 joules of energy.
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Now, let's look at the energy that this can produce. Considering the 50lb brass weight inside (23kg) and the 48in it will fall (1.2m), we have:
U=23kg*1.2m*9.8m/s^2=270 joules
This thing has a potential of producing 270 Joules of energy if 100% efficent.
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270 J is three orders of magnitude off of 120 kJ. I hate to poo-poo on a fellow hokie, but I think this guy's being a bit liberal with the numbers. - 1iProd, on 02/21/2008, -5/+123No way, gravity is very pricey nowadays.
- bossm4n, on 02/21/2008, -2/+109He needs a gravity powered server that lasts for more than 200 diggs.
- kronso23, on 02/21/2008, -14/+114I don't see YOU inventing a gravity lamp.
- ja4444, on 02/21/2008, -2/+91Silly student, gravity makes heavy, not light.
- jmpeagle, on 02/21/2008, -3/+79so what won first prize if this won second?
- Thuktun, on 02/21/2008, -26/+101"lasts 200 years" means the materials will last that long"
In contrast with something using elaborate parts that wear out every year. Nobody was suggesting the device would produce light without attention for 200 years. - morcheeba, on 02/21/2008, -1/+76Maybe it's only for use on planets with a gravity of 3800 m/s^2
- jemka, on 02/21/2008, -2/+64Marty: Whoa, this is heavy.
Doc: There's that word again, heavy. Why are things so heavy in the future. Is there a problem with the Earth's gravitational pull? - tehbeermang, on 02/21/2008, -5/+66Even with it's faults, I'd like to see one in person.
- hoisen, on 02/21/2008, -9/+68I like cats
- d00zt1n, on 02/21/2008, -10/+68Gravity light, will be very cool, hopefully it will be cheap
- Radical5, on 02/21/2008, -0/+55where can I buy this "gravity"???
- NotOptium, on 02/21/2008, -2/+52ANTIGRAVITY LIGHTS!!
- daborg, on 02/21/2008, -2/+50Typical of Digg to make light of a breakthrough like this.
- elnerdo, on 02/21/2008, -3/+50Like the sun.
Interestingly, the sun IS a gravity lamp, Gravity crushes atoms, atoms emit light. - greenlight2001, on 02/21/2008, -1/+42By one look at your mom, I'd say gravity has it's hands full.
- snowskate22, on 02/21/2008, -15/+54Hmm... seems kinda Hokie to me
- arcooke, on 02/21/2008, -2/+40According to you, my hard drive should weigh 1,092,266,665 lbs @ 2.17 lbs / KB.
- Kingster, on 02/21/2008, -6/+40Here's some more info on it... http://www.core77.com/competitions/greenergadgets/ ...
Looks like the weights, rather than just falling, actually spin an axle hooked to a gear that spins neodymium magnets (acting as a rotor) inside the base (that acts as a stator). Pretty frickin' cool, if ya ask me. I'd buy one. - Devrdander, on 02/21/2008, -4/+38the jerk store called, they're running out of you!
- turpenine, on 02/21/2008, -15/+48your mom
- chubbybubba, on 02/21/2008, -0/+31What we need is light powered by Diggers lost hopes and dreams. That thing would be brighter than the sun!
- blazes816, on 02/21/2008, -1/+30Plus, anti gravity lamps are way cooler.
- pixeldust, on 02/21/2008, -0/+25The fact that most people don't want to lift freaking 50 pounds to turn on their light?
- sdellboy, on 02/21/2008, -3/+28Homer: "Lisa, in this house, we obey the laws of thermodynamics!"
- lemekim, on 02/21/2008, -18/+43Buried for violating the First Law of Thermodynamics
- Murdats, on 02/21/2008, -1/+26maybe we could create some sort of mechanism to lift the stuff for us, maybe power it off electricity.
- rogersj3, on 02/21/2008, -3/+28Sorry - I don't mind your comment, but I have a policy to dig down all who request it.
- FoolsRun, on 02/21/2008, -0/+24It's so simple!
- bromac, on 02/21/2008, -0/+24The object is called a weight. It has a mass of 23kg. For example, you lift weights, not masses.
Smart ass. But don't worry, this thread's full of them. - countingthedays, on 02/21/2008, -1/+25Regardless of how the device is constructed, there is a limited amount of energy at hand here. If you put 270J in, thats all you can get back in light. The original poster was spot on.
- Synova, on 02/21/2008, -0/+24Like putting too much air in a balloon!
- inactive, on 02/21/2008, -1/+24I wouldn't. After a few years it apparently gets crazed, and then god knows what will happen.
- inactive, on 02/21/2008, -2/+24Not if Big Oil denies the existence of gravity like it did Global Warming.
- pyro789x, on 02/21/2008, -2/+24@pixeldust
I would gladly lift various weights to power my home if it means I won't have to pay a dime for the energy I use. Hell, that would just help to keep me in shape. I need the exercise anyway. - dupswapdrop, on 02/21/2008, -7/+28Nice idea kind like a grandfather clock.
- theymos, on 02/21/2008, -0/+21Good idea! But to save money, why don't we use something to generate the needed electricity ourselves; perhaps involving gravity?
- badjoke, on 02/21/2008, -1/+21I prefer turtles.
- yunus, on 02/21/2008, -1/+201.21 gigawatts!
- chrispeters, on 02/21/2008, -6/+25This lamp can only start with so much potential energy. You can't create energy out of thin air, so it either needs a massively heavy weight on it, or needs to fall an incredibly high distance. It doesn't matter how good the design is, it's simply not possible.
- alexidoid, on 02/21/2008, -7/+25My guess is that you don't understand physics entirely.
- dinostabOMG, on 02/21/2008, -1/+19Was that easier than typing "23kg to lb" in Google? Or indeed multiplying by 2.2?
- 11familyguy11, on 02/21/2008, -0/+18http://www.core77.com/competitions/greenergadgets/
- kh99, on 02/21/2008, -4/+21We get that. The point is that it can't possibly emit light for even 4 hours. You're telling people to read when you apparently haven't even read the comments you're replying to? Idiot.
- badjoke, on 02/21/2008, -1/+18I guess we know who won the creativity award.
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