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Page 5
The principles of thermodynamics aren't limited to experiments; we use these principles every day:
Designs for objects such as a thermos use a vacuum or air-filled cavity to slow the transfer of heat, because the transfer of heat can be very slow across an area without a physical connection (contact with a solid). Thus, by separating the inside and outside layers of the thermos, the temperature changes much more slowly within the thermos since heat cannot move quickly.
We see thermodynamics used in plastics for pot handles and for coolers, as plastic also slows the transfer of heat. Its higher specific heat means that it changes temperature more slowly, requiring more energy to change temperature.
Fans and insulators in computers are used to divert heat from processors and other parts of the computer to keep it from overheating. They move the hot air out of the computer quickly enough to keep the temperature in the computer parts, some of which have low specific heats and so can change heat quickly, and thus prevent damage.
These principles can be used to do incredible tricks as well. Did you know that “fire walks” where a person walks across flaming charcoal without getting burned can be done because the specific heat of skin is high enough that the transfer of heat is slow. So long as the person moves quickly, they won’t get burned.
This can also be applied to the use of gases for a variety of purposes. Now remember how we talked about that in a hot air balloon, heat makes the air expand? This actually is true for all gases, and is controlled by something called the Ideal Gas Law. Without going into too much detail, the law explains how pressure, volume, temperature, and the amount of a gas present are all interrelated. The equation is PV=nRT. P is the pressure of a gas, V is the volume of the gas, n is the amount of moles of a gas (Moles are a measure of quantity. One dozen = 12 units. One score = 20 units. Similarly, one mole = 6.02*10^23 units, a very, very large number.), R is a constant based on the type of gas involved, and T is the temperature in Kelvin.
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