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In the summertime, perhaps you have gotten out-of a pool and then felt cold standing in the sun? That's as the water in your skin is evaporating. Visiting  [http://rahnindustries.com/ booster coil article]  seemingly provides lessons you could use with your brother. The air carries off the water vapor, and with it a number of the heat will be taken away from your skin. This is similar to what goes on inside older refrigerators. Rather than water, though, the ice box uses chemicals to-do the cooling. You can find two things that need to be known for refrigeration. 1. A gas cools o-n expansion. 2. This novel  [http://rahnindustries.com/ consumers]  URL has uncountable dynamite tips for the purpose of this activity. When you have two things that are different conditions that effect or are near one another, the hotter surface cools and the surface warms up. This can be a law of physics called the 2nd Law of Thermodynamics. Old Appliances If you look at the back or base of an older fridge, you'll visit a long thin tube that curls back and forth. This tube is connected to a pump, which is operated by an electrical motor. If you have an opinion about religion, you will likely fancy to discover about  [http://rahnindustries.com/ website] . Within the tube is Freon, a form of fuel. Freon is the manufacturer of the fuel. That fuel, chemically is called Chloro-Flouro-Carbon or CFC. Learn new information about  [http://rahnindustries.com/ www]  by visiting our refreshing link. This gas was found to hurt the environment if it leaks from appliances. So now, other substances are used in a slightly different approach (see next section below). CFC starts as a fluid. The pump forces the CFC through a lot of rings inside the freezer area. There the substance turns to a vapor. When it does, it eats up a few of the temperature which may be in the freezer compartment. Since it does this, the rings get colder and the fridge starts to get colder. Within the part of your icebox, there are a bigger place and fewer coils. Therefore, less heat is soaked up by the coils and the CFC steam. The pump then sucks the CFC as a steam and forces it through pipes which are on the outside of the refrigerator. By compressing it, the CFC turns back in a liquid and temperature is given off and is absorbed by the air around it. That's why it might be a bit hotter behind or under your refrigerator. The liquid is able to go back through the freezer and refrigerator over and over, once the CFC passes through the exterior circles. Today's Refrigerators Contemporary refrigerators don't use CFC. Alternatively they use ammonia gas. Ammonia gas becomes a fluid when it is cooled to -27 degrees Fahrenheit (-6.5 degrees Celsius). A motor and compressor pushes the ammonia gas. When it's compressed, a gas heats up as it is condensed. Its heat can be lost by the hot ammonia gas to the air in the room, once you move the compressed gas through the coils on the back-or base of a contemporary ice box. Remember what the law states of thermodynamics. As it cools, the ammonia gas can alter into ammonia water because it's under a top pressure. The ammonia liquid passes through what is called an expansion valve, a little small gap that the liquid has to fit through. Between the compressor and the valve, there is a low-pressure region as the compressor is taking the ammonia gas from that part. It boils and changes into a gas once the liquid ammonia strikes a low-pressure area. That is called vaporizing. The coils then go through the freezer and normal part of the refrigerator where the ammonia in the coil pulls the heat from the compartments. This makes the interior of the freezer and entire ice box cold. The cold ammonia gas is sucked up by the compressor, and the gas goes back through exactly the same procedure over and over. How Does the Temperature Remain the Inside? A device called a thermocouple (it's generally a thermometer) can sense when the heat inside the fridge is as cold as you would like it to be. When it reaches that temperature, the system turns off the energy to the compressor. However the fridge is not com-pletely covered. There are places, like round the doors and that may flow slightly, where in fact the pipes undergo. Then when the cold from inside the refrigerator begins to the heat leaks in and flow out, the thermocouple turns the compressor back to cool the refrigerator off again. That is why you'll hear your fridge compressor engine coming on, running for a little while and then turning it-self off. Today's appliances, but, have become energy efficient. Ones sold to-day use about one-tenth the total amount of energy of people that were built 20 years ago. So, for those who have an old, old ice box, it's better to buy a new one because you'll cut costs (and energy) over an extended period of time. To learn more go to: Argone National Laboratory - Ask A Scientist (http://newton.dep.anl.gov/newton/askasci/1993/eng/ENG30.HTM) Mr. Hand's 8th Grade Science Site (www.mansfieldct.org/schools/mms/staff/hand/heatrefrig.htm) How Stuff Works - Icebox (www.howstuffworks.com/refrigerator.htm) Technology Treasure-trove - ice box page (www.education.eth.net/acads/treasure_trove/refrigerator.htm).