Non – stop engine (II)

Agreed.

Unfortunately, we've got a few more like him: Mazulu, river, and DaS Energy come to mind. Luckily, following his first short ban, that last one seems to have gone away.

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Perhaps this ignorant troll will eventually do the same...

 

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No; it's a one way street. Energy eventually ends up as heat and there's no re-converting it back into useful motion. (See the Second Law of Thermodynamics.)

Only Brownian motion, which is heat energy. If you are talking about Brownian motion then yes, that will go on forever. Indeed, the Second Law of Thermodynamics insists upon this. At some point the universe (if it does not collapse upon itself) will reach a state of maximum entropy, also called "heat death." At that point nothing can extract energy from the heat of the universe because there are no temperature differentials and thus no way to utilize that heat energy. Everything will come to a stop. (With the exception of Brownian motion of course.)

You have completely missed the point of that. I will try to state things more simply in the future.

No, the friction warms it up. The heat transfer from your ears to the air cools them down, and does so more quickly if there is more air present (i.e. the air is being moved across your ear.) Normally the second phenomena dominates. However, if you were moving fast enough (around 1200 mph) then the first would dominate and your ears would get very warm indeed.

Now, I understand you don't eat bacon. Let's say you stopped eating everything. Eventually you would cease to be exothermic, and your ear would cool down to the temperature of the surrounding air - because you are no longer generating enough energy to keep that heat flow going. If the wind were strong it would be SLIGHTLY warmer due to friction but not noticeably so.

Are you saying that the at the end of a star's life it turns into a rocky planet like Earth? Interesting theory.

It will - just like the Moon did.

Of course it won't. If it did, ice would form at the bottom of the sea. Water expands when it gets below a certain temperature, as do many other materials. Other materials experience very little expansion when heated and thus do not rise very much.

Also note that "hot air rising" has nothing to do with the energy of the air making it move. It is due to buoyancy, which is a product of gravity and Boyle's law. A sphere containing argon at very low pressure, at close to absolute zero, will rise just as well as a hot air balloon provided its volume and mass are similar.

 

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@thinhnghiem:

You have given different orientations for the magnets. If they are like poles facing, then having the dragonfly counterpoised on a pivot is distracting you from seeing that the set-up is just about gravity vs. magnet like pole repulsion (levitation). This video shows the basic forces at play:

http://www.youtube.com/watch?v=OEExd0wlsPo

 

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It must be to much like rocket science. An engine burns fuel and then the energy sends the jet at supersonic speeds. It really must be a really difficult concept to understand. Welcome to the 21st century.

 

?? No, it's very simple. A jet engine uses heat TRANSFER to propel itself. If it just had HEAT (i.e. something at a given temperature) - and that heat was not transferred anywhere - it would go nowhere.

 

Nah, it would just explode like a bomb. Heat is the vibration of atoms. So something feels hot because the atoms are in motion traveling back and forth. This is like grade school science. I don't see why no one can back me on this. If two atoms come into contact with each other then they transfer that motion to the other atoms. That is why it is said that heat always travels from hot to cold. If the atoms are vibrating faster than they nock each other farther away from each other. If they are farther away then they become less dense. If they are less dense then it will rise due to boyancy. Heat is the motion of atoms.

 

My emphasizing is that the tail of dragonfly does not stay motionless finally. Instead, it vibrate slightly surrounding the counterbalance point

 

Heat is energy. It doesn't rely on matter, if that's your point. It can simply exist as radiance.

 

I was trying to dumb it down into a language that people could understand. I guess you are talking about electromagnetic radiation? The electomagnetic radiation excites atoms giving them an increase in energy and heat. The amount of energy is associated with the frequency of the electromagnetic radiation. It would then have to come into contact with atoms inorder for that energy to be transferred into heat. Tempurature doesn't change from a particles frequency alone.

 

Not at all. Try this experiment:

Heat up a kettle of water. It now contains a quantifiable amount of heat. Put it in an insulated box. Note if it explodes. It will not; it will simply retain the same amount of heat.

I think because some of us took some science past grade school

Often but not always. Google the density of water at 38F and at 33F.

 

Okay, I tried it. The water kept moving because it started to boil and it foamed up and overflowed over the top. How did you get yours not to do that? Did you watch it? I didn't watch mine and it ended up all over the place.

 

Energy can exist in many different forms, one of which is heat. Heat can exist as particles in motion, which is associated with temperature; or it can exist as radiation. An example of heat radiation is the infrared that lights up warm objects against a cool background in night vision goggles. Another is the radiation of the heat of the earth into deep space. The loss of that energy reduced the temperature of the mass, condensing it from gas (or plasma) to liquid, to its present state, in which the mantle is nearly completely solid. (As an exercise you could try to estimate how long it took the earth to cool from molten to solid phase, and then estimate how much energy was lost to radiation).

You can use this analysis to estimate the average velocity of a molecule of gas at a given temperature. If you assume that it's not losing any heat (perfectly insulated) you can estimate the average ("mean-free path") velocity of an individual molecule, by assuming that all of the energy at the given temperature, nRT/n = RT, converts to kinetic energy, 1/2mv[sup]2[/sup], where v is the avg. velocity and m is the mass of the molecule.


By the same token you can estimate how much heat is gained from, or lost to, radiation, over a given time by measuring the initial and final temperatures. In this case, E[sub]radiated[/sub] = n R (T[sub]final[/sub] - T[sub]initial[/sub]).

And yes, the radiation is electromagnetic, often observed as infrared. A microwave oven exploits heat radiation at a much lower frequency, around 2-3 GHz, which is a resonance band for water molecules, and therefore an efficient way to heat food.

The amount of heat energy radiated is in part related to frequency, as you note, but also related to amplitude. Thus, I can either generate 100 J f heat energy with an heat lamp, in the infrared band, or I can do so with in the microwave band (or any other frequency). Note, I can power both devices from a 60 Hz outlet; thus the energy at 60 Hz has an equivalent amplitude for each device. Similarly, I can double the energy by doubling the amplitude (averaged over 60 Hz) by using two heat lamps.

Temperature doesn't change from a particle's frequency alone? At a quantum level, but not at the practical scale. In a gas, we would be more interested in the kinetic energy of the molecule, rather than the internal frequencies of its particles.

 

Water doesn't "foam up". If your pot boils-over, it contains more than just water.