DimaSaif

Physics 1010

Jennifer Noon

Discoveries in Thermodynamics

There had been many amazing discoveries done by scientist about thermodynamics in which today we have answers to. But imagine if you did not have those answers, could you explain heat and cold? How does heat transfer and by what? What is thermodynamics and are there any laws to it? What is temperature and how it can be measure by a thermometer and last what is and how does refrigeration work. I think we would all be lost right now, thermodynamics explains many of the things that is happing around the earth and things that we are experiencing in our daily lives.

First of all how do we indicate warmth? First of all you should know that all matter, solid, liquid and gas have continuously jiggling atoms or molecules. Of this random motion they have, the atoms and molecules in matter have kinetic energy. This kinetic energy of the individual particles produces an effect that we can sense which warmth is. Warmth is indicated with respect to some standard is called temperature, where now we have the thermometer for measuring temperature. Thermometer was first invented by Galileo in 1602. In a mercury or alcohol thermometer the liquid expands as it is heated and contracts when it is cooled, so the length of the liquid column is longer or shorter depending on the temperature. Modern thermometers use standard temperature units such as Fahrenheit or Celsius (Bellis). When measuring temperature with a thermometer you should take note that the thermometer should be small enough that it doesn’t appreciably alter the temperature of what is being measured.

Now imagine if you touch a hot stove, why does the heat go up to your hand quickly? The answer to that question is simple; energy enters your hand because the stove is warmer than your hand. Now imagine if you touch a piece of ice, why does it feel cold? Easy, energy transfers from your hand into the colder ice. The direction of spontaneous energy transfer is always from a warmer object to a cooler object. The energy transferred from one object to another because of temperature difference between them is defined as heat, heat energy transit from a body of high temperature to one of lower temperature. Now you may thing that the definition of cold is just as the opposite of heat. Actually, there is no real scientific definition of cold, but cold is viewed as the absence of heat.

Well how does energy move from one place to another? The answer is heat transfer. Heat transfer is the process of moving heat from a location where much heat exists to another location. Heat transfers happen in three ways: conduction, convection and radiation. Let’s start out with conduction, which is one of the most common ways to transfer heat. Conduction is done by transferring heat through matter from one atom to the next. Example of that is, when you leave a metal cooking spoon in a hot liquid for long you experience conduction. The second is convection is the actual physical movement of heat from one place to another by liquid or gas. Last is radiation, which is responsible for most warmth that our planet receives. Radiation happens when heat travels with electromagnetic waves. (Black)

Thermodynamics was first coined by Kelvin, it stems from the Greek words meaning “movement of heat”. The two foundation stones of thermodynamics are the conservation of energy and the fact that heat flows spontaneously from hot to cold and not the other way around. Thermodynamics provides the basic theory of heat engines. The laws of thermodynamics dashed the dreams of inventors and industrialist who believe in the possibility of a perpetual motion machine. I am going to being the study and law of thermodynamics with the lower limit to temperature. (Paul)

Thermodynamics has three laws which they are: First law of thermodynamics, Second law of thermodynamics and third law of thermodynamics. I’ll start with explain the first law of thermodynamics

First law of thermodynamics is when heat flows to or from a system the system gains or losses, an amount of energy equal to the amount of heat transferred. “System” is a well- defined group of atoms, molecules, particles or objects. It may be earth’s entire atmosphere or even the body of a living creature. But the important point we need to know is that we must be able to define what is contained within the system and what is outside of it. When you add heat to a system it does one or both of two things: 1. It increases the internal energy of the system, it it remains in the system and/or 2. It does work on things external to the system if it leaves the system.

The second law of thermodynamics is heat of itself never flows from a cold object to a hot object. In winter heat flows from inside a warm place to the cold air outside but in the summer heat flows from the hot air outside into the cooler areas, that direction is from hot to cold. If you want to change the direction of the flow to make it from cooler to warm you have to work on the system by adding energy from another source.

The third law of thermodynamics is the absolute zero. Absolute zero is the lowest possible temperature that a substance may have; the temperature at which particles of a substance have their minimum kinetic energy. This temperature is about - 273.15° Celsius, or -459.7 Fahrenheit. The third law of thermodynamics says: “The entropy of a pure perfect crystal is zero at zero Kelvin. Entropy is a property of matter and energy which was discussed by the Second law of Thermodynamics. The third law of thermodynamics means that as the temperature of a system approaches absolute zero, its entropy approaches a constant which is zero. When the crystal is pure and perfect, that means that every molecule is identical. On the other hand if the crystal is non-pure or less perfect, there will be imperfections with the molecules, so the entropy cannot become zero.

Our last discussion is refrigeration. Refrigerator is any kind of enclosure; like a box or cabinet, whose interior temperature is kept substantially lower than the surrounding environment. The term “refrigerator” was created by Thomas Moore, in 1800. Moore designed it as a mean for transporting butter from rural Maryland to Washington, DC. Its operating principle was the latent heat of fusion associated with melting ice. A refrigerator comprises a thermally insulated compartment and a heat pump-chemical or mechanical means-to transfer heat from it to the external environment, cooling then contents to a temperature below ambient. A refrigerator maintains a temperature a few degrees about the freezing point of water, the average temperature to keep food cooled is about 3 to 5 °C. The refrigerator is a relatively modern invention among kitchen appliance. For centuries a refrigerator was called an “ice box”, which is why now day’s some people may refer a fridge as an icebox.

My thought behind all of this is that, personally I think I would hate leaving in time where I didn’t understand or have what we understand and have today. There are smart people around the world and I am thankful for that. The discoveries that we each make, makes a big impact on many people’s life. Like refrigeration, today most of our food will be routine and we will have a nasty smell around, but thanks to the discovery and creation of that, now most of the household members have refrigerator to keep things stocked up. Maybe I might be the first, but I learned a ton from this essay, such as I didn’t know that there was no such thing as “cold”. I thought that cold had a definition and heat had a definition but I guess I was wrong.

The amazing discoveries of thermodynamics changed our lives fully. Now a day we cannot imagine ourselves without the heat sources that we have. We can now build things to create heat transfer, we understand the process of heat and cold and who to warm up or cool down on such days. We understand what is temperature and how it works, which is how we now know if we caught a cold or not, or whiter it’s a good day to go out for a picnic or not. But also the most important thing of all is our refrigerators, without it, will now we would not have some of our food good nor our tasty pastries. Thermodynamics is a wonderful process which we are still working on and discovering many other things to make life easy but make it to the better.

Work Cited

  • Black, . "What is heat transfer." Wise geek (2010): n. pag. Web. 5 Dec 2010. <
  • Elert, Glenn. "Refrigerators." Physics Hypertextbook (98-10): 1. Web. 5 Dec 2010. <
  • Hewitt, Paul. Conceptual Physics. 11th. Petersburg: Pearson Education, Inc., 2010. 269-228. Print.