https://www.youtube.com/watch?v=Jsc-pQIMxt8
Isn't it wrong to say that gravity is doing the job? I mean, it's basically potential energy (mechanical = potential + kinetic). In both the clock and I presume the light as well, they're using the potential energy from lifting those weights up and letting them slowly pull the mechanism. I know, of course, that it's gravity acting on the weights. I just think the terminology is a bit ... iffy.
Gravity is doing the job. It's just a very smart way to produce light efficiently and at a very low cost so that poor countries can benefit from this ingenious invention.
K
Quote from: josephpalazzo on December 09, 2015, 10:33:57 AM
Gravity is doing the job. It's just a very smart way to produce light efficiently and at a very low cost so that poor countries can benefit from this ingenious invention.
No. The lifting the weights are doing the job. Not gravity. (The total job made by gravity is 0)
Quote from: facebook164 on December 10, 2015, 11:59:12 AM
No. The lifting the weights are doing the job. Not gravity. (The total job made by gravity is 0)
Well, that requires full disclosure: input =output. You input the energy -by lifting the weights; the output is gravitational energy converted to light. You get an "F".
Quote from: josephpalazzo on December 10, 2015, 01:38:22 PM
Well, that requires full disclosure: input =output. You input the energy -by lifting the weights; the output is gravitational energy converted to light.
Which really isnt that insightful. The gravity is a red herring. You could equally well power this with a rubber cord or a mechanical spring. (Which indeed may be a better product for climbers etc. not requiring a heavy stone)
Quote from: facebook164 on December 10, 2015, 02:27:09 PM
Which really isnt that insightful. The gravity is a red herring. You could equally well power this with a rubber cord or a mechanical spring. (Which indeed may be a better product for climbers etc. not requiring a heavy stone)
Nope. Gravity is essential to make this thing work cheaply. The rubber chord would need some sort of constant supply of energy, ditto for the mechanical spring. In a poor country, all you need is someone to lift the weights -Read: cheap labor- once every several hours, and let gravity do the rest to give lighting in areas where young children can do their reading or whatever activity needs to be done once the sun has set down and the activity has to be completed before going to bed. If you can think of providing cheaper lighting, please let me know. So far, you still get an "F"... ;-).
Quote from: josephpalazzo on December 10, 2015, 04:39:17 PM
The rubber chord would need some sort of constant supply of energy, ditto for the mechanical spring.
You ever heard of a mechanical clock requiring constant supply of energy? It doesnt. You wind it up and then it runs on the energy in the spring.
Quote from: facebook164 on December 10, 2015, 08:15:37 PM
You ever heard of a mechanical clock requiring constant supply of energy? It doesnt.
That is contradicted by your next statement...
QuoteYou wind it up and then it runs on the energy in the spring.
Fail.
Quote from: josephpalazzo on December 11, 2015, 08:42:34 AM
That is contradicted by your next statement...
Fail.
?
No energy is provided until the spring is winded up again.
Quote from: facebook164 on December 11, 2015, 10:25:21 AM
?
No energy is provided until the spring is winded up again.
Think again: you winding the spring is the constant source of energy that must be provided.
Quote from: josephpalazzo on December 11, 2015, 10:46:10 AM
Think again: you winding the spring is the constant source of energy that must be provided.
Noone needs to wind constantly. The energy is provided in bursts = the winding. During and between the windings the spring provides the energy contantly.
Quote from: facebook164 on December 11, 2015, 10:52:55 AM
Noone needs to wind constantly. The energy is provided in bursts = the winding. During and between the windings the spring provides the energy contantly.
You're still missing the point: in the op, the winding of the spring is done by the lifting of a weight, which when released provides the constant source of energy. The difference being is that by having the option of placing different weights, you can provide different amount of energy which can be easily adjusted to provide the right amount of light and for whatever duration you need to keep the light on. In your case, once you have constructed your spring, if the winding provides little or not enough energy then to make any adjustment, you would need to rebuild your apparatus with different springs in order to get the energy large enough to provide lighting for a certain amount of time. Secondly, bigger spring to provide greater amount of energy is more expensive - weights, you can use whatever is available, hence the availability to more energy for the lighting is a lot more convenient and cheap.
Quote from: josephpalazzo on December 11, 2015, 11:13:58 AM
You're still missing the point: in the op, the winding of the spring is done by the lifting of a weight, which when released provides the constant source of energy. The difference being is that by having the option of placing different weights, you can provide different amount of energy which can be easily adjusted to provide the right amount of light and for whatever duration you need to keep the light on. In your case, once you have constructed your spring, if the winding provides little or not enough energy then to make any adjustment, you would need to rebuild your apparatus with different springs in order to get the energy large enough to provide lighting for a certain amount of time. Secondly, bigger spring to provide greater amount of energy is more expensive - weights, you can use whatever is available, hence the availability to more energy for the lighting is a lot more convenient and cheap.
More Convenient? No! Cheaper? Maybe but a spring is also cheap.
Tut-tut ... a source of light provided free by the UN, is cheapest in the Third World, no matter what kind it is ;-)
I am surprised, on behalf of readers, nobody has posted ... the math is very simple ...
Conservation of Energy:
E=K+V+T
E=total energy
K=kinetic energy (that provided dropping of weight)
V=potential energy (that provided by raising the weight)
T=energy lost to friction
You raise the temperature of the room a little, each time you use it. Also the kinetic energy is converted to light, and that is eventually converted to heat. The conversion from kinetic to light energy is also not 100% efficient, and that also is converted to heat. Eventually thanks to whatever raises the weight, the darkness returns, and the light ceases.
What of it? What you say applies to every source of light, including the sun.
I think a great commercial application of this is attach it to a garage door. Opening the door activates the light.
Quote from: Hakurei Reimu on December 12, 2015, 07:52:17 PM
What of it? What you say applies to every source of light, including the sun.
And in a sense, the Sun is powered by gravity. I think the original controversy of this string ... has to do with primitive cause/effect thinking.
Quote from: Termin on December 12, 2015, 09:52:00 PM
I think a great commercial application of this is attach it to a garage door. Opening the door activates the light.
You realize that requires the door to, slowly, close?
Quote from: Baruch on December 12, 2015, 10:06:47 PM
And in a sense, the Sun is powered by gravity.
No, the process is enabled by gravity but it is not powered by it.
Physics semantics... ech.
Quote from: facebook164 on December 13, 2015, 01:33:52 AM
You realize that requires the door to, slowly, close?
Quote from: facebook164 on December 13, 2015, 01:35:27 AM
No, the process is enabled by gravity but it is not powered by it.
Hey, this obliges me to upgrade your report card from an "F" to a "B
+".