One day when listening to yet more random talk about Global Warming, I had some thoughts about heat, that have been eating at me for some time now. So tonight I decided to try to address these thoughts, and document them here - thereby forcing me to vocalize them, and see if I'm just being dense or not.
The big question is "Where does the heat go?". Such a simple question, but when you start looking into the answers, it's really a complex topic.
Lets start with a simple experiment - put a pot of water on the stove and heat it to boiling. Its a given that the water will be hot at that point, and so will the pot and stove. Now, turn off the stove, and let the pot sit there for a number of hours. The water, pot, and stove will cool off, and return to room temperature.
This is where my question applies - all that heat, which is nothing more than a form of energy, seems to disappear. Well, the easy comment is that the heat is disapating to the air around the stove. And I'm sure that is happening. But then the laws of physics come into play.
There is a law in physics (a law is something that has been proven, whereas a theory has not been proven) that states that the total amount of energy does not change. This law is known as "The law of conservation of energy" So, if it takes X amount of energy to heat the water, that energy is not lost. Now, if that is true, then one would think we have now added X amount of energy to the air around the stove. (I'm simplifying here - other things would also receive this heat energy, such as the stove itself, the counters nearby, etc.).
So now we have raised the temperature of the air. This excess energy would also be passed to the air or items that come into contact with our heated air. So the overall average increase in temperature would slowly spread to other things, with each item having less and less energy to pass on, and the room would once again return to a stable temperature.
But now, consider the bigger picture. By using this electrical energy, we have caused the overall heat of our house, and the items around it, to increase - even if it was only a few decimal points of a degree. But over time, wouldn't the heat keep increasing? Now, when we have a forest fire, or large industrial plants venting their excess heat into the air, aren't we raising the overall temperature of the planet?
People have told me that excess heat on earth is disapated into outer space. And this makes sense as well. But that same law of physics comes into play again - isn't this heat adding energy to the space around earth? Sure this heat gets spread throughout space, but then one would think the overall temperature of space is increasing. But I haven't heard any news on this - either locally, globally, or astronomically, other than this concept of Global Warming. And some scientists have stated that the earth has seen this heating behavior before, so Global Warming may not be caused by mankind.
So where does all this heat or energy go? That's the question thats been bugging me. Tonight I did a (very) quick search of Google. The results are a little odd - everything from thermal dynamics, to using temperature masses to regulate the environment in a building, to removing heat from a chicken. Some of these articles do pose the question "where does the heat go", and some mention the law of conservation of energy. But I've yet to find a site that definitively says "this is what happens to the heat".
So, that leaves me to speculate for now. This is one of those types of questions that I'll pick up off and on throughout my life and look into it more. Maybe I'll even find a definitive answer, or someone more knowledgeable than me will see this blog entry and enlighten me. For now though, I'll speculate, hypothosize , and research...
Onto the speculation!
The very first thought that crosses my mind is that the law of conservation of energy states that while the overall amount of energy does not change, the form the energy takes does. There are concepts of chemical energy, mechanical energy, potential energy, and even more types of energy. But energy is energy - according to the law - no matter what form it is in. So, it could be this excess heat energy is converted into another form of energy.
I have an interest in physics, so have tried to read some interpretations of Einstein, and others. Most of this is way over my head, but I can read the words at least and gain some knowledge through memory - if not true understanding. One of the concepts I read about (I think it was from Einstein), is that an item can have potential energy. Imagine taking a book and holding it in the air - if you were to let go, gravity would take over, and the book would then be showing a form of energy (i.e. it's falling). But while you are holding it, it has a potential to fall, so it has potential energy. It's been demonstrated that when an atom is heated (energy is added to it), the electrons get more energetic than they were before the heat was added. So, adding heat seems to be converting the potential energy into heat energy. When that atom then cools off, the electrons slow down. This would seem to be showing a conversion of the heat into potential energy. So maybe this is all there is to the question "where does the heat go?".
This concept of potential energy is intriguing to me - could it be that something as small as your hand, or even smaller, has enough potential energy to power a house? Can we tap that potential energy without destroying the source, or the surroundings? We know that we can convert a volume of gas to energy, but then we have used up (or destroyed) that volume of gas. If that gas was converted to energy rapidly, we end up with an explosion, and damage things nearby. But if we could tap the potential energy in some way, without using up or destroying the gas, and allow the gas to return to it's resting state, would we have an endless supply of energy? Can we do this with something not prone to blowing up, like maybe a rock? There are plenty of samples of using potential energy, but it's a one way process. Think of any hydro-electric dam - the water falls down a chute, converting it's potential energy into kinetic energy (i.e. it's falling), this water then flows through a turbine, turning it. The turbine is connected to large generators, which convert the kinetic energy into electrical energy. But the water can only be used once - the act of pumping the water to the start of the process tends to negate the gain in energy.
This quickly brings us into the concept of perpetual energy - something the keenest minds in the world say can't be done, but can't really prove either. I've heard of a fellow in Saskatchewan, Canada, who attached an electric motor to a generator via a simple pulley and belt, and then pulls on the generator to get it turning. The turning generator creates electricity, which is then fed back to the electric motor. The motor turns a shaft/wheel that is connected to the generator. According to those keen minds, this contraption should not work, or may work but will fail over time due to friction and inefficiencies. But the fellow says he can hook a light bulb to the contraption, thereby diverting some of the electrical energy from the task of turning the generator, and it just keeps going. Isn't this a form of perpetual energy? Even if it's not, even if the contraption only works for an hour or two at a time, isn't it generating enough power to charge up a battery for later use?
The concept is tantalizing - free (or cheap) energy for little work, with little dangers.
I once had an idea for a similar type of generator. I was in high school, and when I asked my physics teacher about it, he told me it could not be done. Well, with all due respect to my teacher - he was the most interesting teacher I've ever had - I don't see why it wouldn't work. The idea was to take a circle of magnets, alternating their poles, and add a spindle with a North or South spindle at either end. Then, the magnetic fields on the circle would be adjusted just enough to attract the end of the spindle initially, then reverse to push away the spindle. Now, with some good timing (you'd probably need a computer for this), you should be able to keep that spindle moving indefinitely. Now, take some wires and insert between the spindle and circle of magnets. It's known that a copper wire (or any conducting surface) will create electricity when exposed to a change in magnetic fields. So our wires would be generating electricity, and the spindle would keep spinning. The question is if we can get enough electricity to power the changing magnetic fields. And even if we could, would there be enough extra to divert to another task. Better brains than mine are working on similar ideas these days, so maybe we'll find our cheap/free energy source very soon.
But potential energy has an even bigger value than that discussed above. Einstien's theory of relativity statss that energy is equal to mass times the speed of light squared (E=MC^2). So, we can then convert energy to mass, and mass to energy. It's not that hard to come up with examples of either - though converting energy to mass is not as common. We know from nuclear research (not to mention some nuclear explosions), that mass contains an awesome amount of energy. It contains potential energy. Imagine what would happen to the world if we could pick up a handful of dirt and slowly convert that mass into electrical energy in a safe and manageable way, but only when the energy is needed. A single grain of sand might have enough potential energy to power a house for months at a time. Unfortunately current technology tends to be an all or nothing deal, when it comes to converting mass to energy. So, that single grain of sand might provide a lot of energy, but most would not be used in a meaningful way, so would be wasted.
Isn't it fun when you start with a simple question and let your brain work through it and make seemingly random, but related, connections to other ideas? The more I think on the topic, the more I feel cheap and safe energy will change the world. Electricity has already done this, but it still costs to produce it (in terms of work done, not in terms of money), at least when considering the amount needed to do anything meaningful. If that mythical grain of sand were to ever become a reality, the world would change. Even more so if we can find an efficient means of electrical propulsion that can be used on earth and in three dimensions (i.e. imagine an antigravity device powered by electricity, and a very cheap, safe, and reliable means of providing that electricity). Ok, maybe this is leaning towards fantasy, but a mere 100 years ago, no one thought we could fly, or travel to the moon.
It all starts with an idea.