/sci/ - Science & Math

>>5402126
>But why can't gravity be used to create power?
It can. Indirectly.

Gravity between the Earth and the moon.
http://en.wikipedia.org/wiki/Tidal_power

>>5402126
the energy would only be created when the boulder is first placed on the device. A split second later (or however long it takes) there will be equal force pushing up of the object. No more energy could be "harvested" from the boulder being on the device.

>>5402135
So why can't we use that force in a more direct way on earth?

>>5402145
True. A device like that would need resetting every time. Every time you lift the rock you use energy from your arm.
Turning a hand crank to generate electricity would be more efficient.

>>5402145
Couldn't a suspension or gas/liquid compression system rebound that motion and keep the falling action repeating back and forth like a piston?

>>5402149
Energy is not magically created. There is always a cost.
The earth is losing it's kinetic energy; it's rate of rotation lessens each day.
Days become longer and longer as the Earth takes longer to rotate on its axis.

The Moon is also escaping the Earth. Slowly.
It gradually gets further away from us as it leaches the rotational gravitational energy of the Earth.

Energy is never free.
Energy can not be created or destroyed.

>>5402153
But there are flashlights that use only the force of you holding down a button to power a small mechanism which powers the light. Why couldn't the static force of a solitary million pound object also power bigger things?

hydro power uses gravity

>>5402156
No.
In order to harvest the energy, you resist the motion of the device.

A 'gas/liquid compression system' requires energy to run.
There would be a net loss.

Forgive me if I am retarded (I didn't have proper education).

But I believe the reason gravitational energy could not be used is because as things fall to the earth they constantly fall faster to the center. So even if you had a frictionless da vinci wheel it would never be able to last forever because gravity would be making it slower.

>>5402165
>Why couldn't the static force of a solitary million pound object also power bigger things?
When the object is at rest, the reaction force is equal to the gravitation force. There is no net gain.
I have never heard of these types of torches. Can you post a link to information about them, please?

It will still cost your body energy to press the button down hard.
The energy is just transferred, not created.

>>5402163
But energy forces from the earth aren't decreasing. A person can't now jump any higher then they could a million years ago. Also you're not addressing the simple force of gravity in it's current state on earth. Right now and for the foreseeable future the earths mass is producing a constant force on all things, this force is significant and predictable. We can harness the power of combustion, aerodynamic lift, hydrodynamics in dams, why can't we harness the power of mass?

>>.5402149

We do : It's the principle of hydroelectric power plants. There's energy, not when there's force, but when there's a force AND movement. Gravity take the water downstream, and we can use the energy of the fall.

But if you want to use earth's gravity to power anything, you need something to go DOWN : from up to down in the gravitionnal field of the earth, you can collect. But once whatever you used is down, you'll need at least as much energy to put it up again and use it again. That's why we use water : that's the only thing that naturally goes up and down again, thanks to evaporation and rain.

>>5402169
No.
It is just that harvesting the energy opposed the movement of the device.
When you power a hand generator, it is difficult and it pushes against you because of the magnetic force.
You do not get the energy for free.
Without something moving it, it will stay still.

A wheel spinning on its own which is not connected to a generator, has kinetic energy, but you are not harvesting any of it.

>>5402167

>A 'gas/liquid compression system' requires energy to run

The suspension in your car uses either gas or liquid compression, it doesn't require power.

>>5402181
>A person can't now jump any higher then they could a million years ago.
This has nothing to do with it.

>why can't we harness the power of mass?
Mass itself has no power.
There is gravitational potential energy between two bodies that are far apart and are attracting each other.
After they have come together, they have lost that gravitational potential energy.

The energy is still not free. It is never free.

>>5402179

>>>5402165
>When the object is at rest, the reaction force is equal to the gravitation force. There is no net gain.

I was thinking of having the mass be gradually moving down against a resistance of a mechanism which would be powered by the force.

>I have never heard of these types of torches. Can you post a link to information about them, please?

Let me get googling, we had them in science class in primary school

>It will still cost your body energy to press the button down hard.
>The energy is just transferred, not created.

Transferring the energy is all I'm going for. Transferring gravitational force into mechanical power.

>>5402187
It's powered by the ambient heat of the sun, otherwise it would freeze and become useless.

>>5402196
Wut?

How is your cars shock absorber powered by the sun?

So much horseshit in this thread

>>5402196
>missing the point this badly

I get what you're saying, but that's like saying jam is powered by the sun.

>>5402163
>energy can never be created
lol E=mc^2

>>5402199
It's constantly receiving energy from the sun, which allows the actions inside the suspension to take place due to the heat.

>>5402341
matter is just another form of energy

>>5402353
What about at night? What about in winter? What about in Siberia? What if you're secretly retarded and no one ever told you? What if this was your retard intervention?

>>5402196
This part is wrong;
you are addressing a completely different aspect of the mechanism than the action.

>>5402126
>But why can't gravity be used to create power?


It is VERY often used for power; a cuckoo clock (weights pulled) and a mill wheel (water raised by rain flows downhill)

But think about it; things only move toward the gravitational center,
so obviously they have a point at which they end.

>>5402165
>Why couldn't the static force of a solitary million pound object also power bigger things?

You are answering your own question:
something FIRST has to move that heavy object, so you are not gaining energy.

>>5402126
We will harness the moon one day OP

One day....

>>5402382
At night- the moon reflects the sun
At winter- Stupid question really
Siberia- look one line up
The rest are for >>5402353 to answer

>>5402431
>>5402353
>>5402196
>>5402167


/o/ here. You fags might be good at dividing in your head or whatever but you motherfuckers are retarded when it comes to understanding how natural science affects (or doesn't affect) everyday machinery.

>>5402374
>matter is energy
No. How's that high school education working out for you?

>>5402181
>why can't we harvest the power of mass?

We can, 'relatively' speaking.

>>5402153
>Turning a hand crank to generate electricity would be more efficient.

no because friction

You're a bad tripfag and should stop immediately.

>>5402181 >We can harness the power of combustion, aerodynamic lift, hydrodynamics in dams, why can't we harness the power of mass?

Learn to energy types

Combustion = Chemical
Aerodynamic lift = Not energy
Hydrodynamics = Potential energy
Power of mass = Does not exist. Also Power != Energy

>>5402163

those it's are hurting my eyes

>>5402187

The suspension is not generating energy. It absorbs kinetic energy created when the vehicle goes over an uneven surface.

>>5402432
>We will harness the moon one day OP

We do.
http://en.wikipedia.org/wiki/Tidal_energy

>>5402181
we harvest the power of mass with nuclear reactors all the time. mass converted to energy

When you're taking the energy from the falling object all that's happening is you're changing the potential energy (PE = weight • height) and converting it to the kinetic energy. If you wanted to use your machine to collect more energy you would have to exert energy to raise it and you would ultimately never create energy. First law of thermodynamics buddy-- energy cannot be created nor destoyed.

in other words.
can this work.

>>5403473
...Why wouldn't that work?

>>5403473

>seal to not let water out and let a ball in

no.

also the string and mass of the ball would weigh the ball down.

friction of those wheel bearings is far too great, regardless of what they're made of.

think of the water being removed, would it work?no. now add what is basically a downward force (water), why on earth would this work?

i can't believe there's a whole thread on conservation of energy.

>>5403553
Uh, the space between the string and the balls could be small enough for surface tension to stop water from leaking out

>>5403553
polymer materials can create near to nothing strings, and there is a tissue type material that is super thin.

the water is there for pressure...

>>5403562

>i am the very high friction required between the balls and the surface to develop this surface tension

>>5403568

>he thinks it would work

the balls would float to the top and sit there. unless of course you know of a "tissue type material" that will bend when required.

>>5403488

Friction

>>5403112
No, they're just retarded. 95% of people on /sci/ are math and science fans.

>>5402144
laughing my dick off

>>5403637
>>5403586
>>5403553
Friction does not have to be considered to break any energy creating device.

What breaks the construction is that balls entering from the bottom must push their volume of water up the tube, which comes at an energy cost.

>>5404205
You fail to remember buoyancy, i see.

>>5404205
That's a good observation

>>5404238
>buoyancy

Buoyancy is caused by the displacement of water (or other fluid). So that upward force is canceled out, as stated above.

>>5403473
>>5404259

That said - hypothetically, suppose you had a frictionless, leak-proof seal at the bottom of the water tank - how long would this run? I suspect it would stop pretty quickly.

The Universe is perpetual.

Shift your frame of reference. ;-)

http://www.youtube.com/watch?v=Ez7M1FDm_2Q

>>5402165
>flashlights that use only the force of you holding down a button to power a small mechanism

I suspect you have to press repeatedly to generate energy over a lengthy period of time.

What about this guys one? Using dem magnets

http://www.youtube.com/watch?v=tlx2PgESXhs

>>5402126

it's possible to use the tides to generate power and there's even other ways but those require a medium to manipulate. The reason that we cannot directly use gravity to create energy is that the gravity is a conservative vector field. This means the work done on an object when being moved from point A to point B is the same amount REGARDLESS of path. This is fucking crazy. This implies that a closed path will be equivalent to not moving the object at all. So there. lrn2math

>>5402126

What is a scale? Ever hear of a pendulum? How about those neat weight-and-pulley systems you've probably seen Jack Sparrow fly about on?

Gravity _is_ power, it is energy, forcibly pushing you down.
Why can't we use this to harvest mad pylons?

Because what goes up, must come down. And vice versa.

>>5402135
>>5403219

>>5404275
It depends on the friction generated by the water, wheels, air, and generator. Although frictionless generator wouldn't generate any power of course.

>>5404275
>That said - hypothetically, suppose you had a frictionless, leak-proof seal at the bottom of the water tank - how long would this run?

It wouldn't run at all.

>>5403120
>hurr hurr it's not energy even though energy can be turned into matter and vice versa

We can argue semantics as long as you want but E=mc^2 proves that mass is energy. Or do you claim that petrol, which has mass, does not power up a lot of shit on our planet?

>>5404485
Are you seriously comparing E=mc^2 to a combustion reaction?

Goddamn you're dumb

Here's your essentially-perpetual-motion power plant:

http://en.wikipedia.org/wiki/Vortex_engine

See also:

http://en.wikipedia.org/wiki/Solar_updraft_tower

It uses the energy from the sun (or from another power plant) to heat air in a spiral, basically creating a tornado to power a turbine. Free energy from the sun, far cheaper and less space-consuming than wind turbines.

>>5404492
but burnt petrol (CO2, H2, whatever) has less mass than the hydrocarbons in petrol.
so E=mc2 is appropriate.

>>5404559
the updraft towers require some serious real-estate but
1) there are plenty of places with a lot of sun and real-estate i.e. deserts
2) the real-estate can be put to other uses e.g. greenhouses

>>5404559

Except these are terribly inefficient unless you create some breakthrough in means of production.

>>5404572
Until you do some high school chemistry and grasp the concept of balanced chemical equations.

>>5404485
>We can argue semantics as long as you want but E=mc^2 proves that mass is energy.
That is not what that proves you completely disregard c in saying that.