Title: Explaining Temperature Scales
Dear Reader,
In your everyday live, sometimes you may wonder how and why the various temperature scales came to be. To the average person, you may only know of the Fahrenheit scale, which we use in the United States, and Celcius, which is used in the rest of the world. On the other hand, there are at least two more. These are the Kelvin and Rankine scales which have more specific uses. In the scientific world, Kelvin and Celcius are the most commonly used because Celcius is based off of the number ten and Kelvin has no negative values. Absolute 0 in Kelvin is a theoretical temperature where there would be no movement of molecules in any state. This has yet to be physically seen. There are boiling and boiling temperatures for each of the temperature scales. For example, the Celcius freezing point is 0 degrees and the boiling point is 100 degrees. For the Fahrenheit scale it is slightly different. The freezing point on the Fahrenheit scale is 32 degrees and the boiling temperature is about 212 degrees. Temperature in Fahrenheit can be converted to Celcius by subtracting 32 degrees and multiplying by (5/9). Then, Celcius can be converted to the Kelvin scale by adding 273.16 to the Celcius temperature. Knowing this, you can determine that absolute zero in Celcius is -273.16 degrees. Kelvin was first thought up in 1848 when Lord Kelvin or William Thomson came up with a system to measure temperature based on the Celcius degree but started zero at “infinite cold.”
In the Absolute Zero Lab, we determined the pressure in psi and the temperature in Celcius of a bulb of gas in different conditions. First, it was in room temperature, then in an ice bath, hot water, and liquid nitrogen. To measure the temperature and pressure, a temperature probe was used and a bulb of air that measured the pressure. Even though common sense would tell you that the temperatures would be different in all of those situations, the pressures differed greatly as well. That’s because the pressure of liquid nitrogen at -196 degrees Celcius is way different than the pressure of the bulb at room temperature. Temperatures taken with the temperature probe need to be changed into Kelvin. With a temperature in Kelvin or a pressure in pascals you can use the Ideal Gas Law (pV=nRT) to find temperature or pressure depending on what you can determine. The many variables stand for pressure, volume in meters cubed, moles, the constant R (8.31J/mol*K), and temperature in Kelvin. The temperatures in the lab varied so drastically, but are an integral part in the study of thermodynamics. The conclusion of the lab was to understand that even with Liquid Nitrogen being extremely cold and other things coming close, finding the absolute zero where no molecules in a substance have any movement whatsoever seems highly unlikely. In fact, fitting with the quantum basics that everything moves at the most basic levels, it is highly unlikely that this can be found. It is more of a theoretical starting point that helps to set a model that we can base our temperature system off of.
In a Molecular speeds lab, the temperature represents the speed of the molecules because heat causes individual molecules to speed up, therefore increasing individual velocities. Therefore, increasing the temperature of a system increases the speed and overall kinetic energy of the entire system. Temperature is also very important when looking at molecular speeds because all of the equations are usually derived from the Ideal Gas Law, which was covered in the Absolute Zero Lab. It is important to know that the molecules and atoms of a gas or other state are always in constant motion. Temperature is a measure of the speed or kinetic energy with which they move. The higher the temperature, the higher the energy associated with those particles. If two different gases have the same temperatures, their molecules individually have the same average kinetic energy. Also, if the temperature of the gas is doubled, the average kinetic energy of the mass of the molecules is also doubled. Therefore, we see that the temperature and average kinetic energy of molecules in a gas are directly proportional and linear. They are directly proportional because as one goes up, the other does too. At higher temperatures, a larger fraction of molecules in a gas are at higher speeds. The distribution of the speeds of molecules at a certain temperature can be graphed. The lines ends up in a normal distribution patterns with a higher fraction of molecules in the middle than at the endpoints(high and low speeds). Because temperature is related to the average kinetic energy, it is also important when looking at the Root mean speed as well. Likewise, if the volume stays the same but the temperature increases the pressure will increase. This occurs because their will end up being more collisions happening between molecules. If pressure stays the same with an increase in temperature, this means that the volume of the gas must increase as well. All of the aforementioned information can be derived by looking at the various situations occurring from altering different variables in the Ideal Gas Law, which is pV=nRT. This equation is the backbone to many of the thermodynamics systems that are important to all aspects of Physics.
Therefore, learn all you can about the various temperature scales and how they affect the world you live in. It may come in handy one day soon. Temperature has everything to do with our everyday lives. It can explain why ice melts or how food cooks.
Until next time,
Brian Jones
Dear Reader,
In your everyday live, sometimes you may wonder how and why the various temperature scales came to be. To the average person, you may only know of the Fahrenheit scale, which we use in the United States, and Celcius, which is used in the rest of the world. On the other hand, there are at least two more. These are the Kelvin and Rankine scales which have more specific uses. In the scientific world, Kelvin and Celcius are the most commonly used because Celcius is based off of the number ten and Kelvin has no negative values. Absolute 0 in Kelvin is a theoretical temperature where there would be no movement of molecules in any state. This has yet to be physically seen. There are boiling and boiling temperatures for each of the temperature scales. For example, the Celcius freezing point is 0 degrees and the boiling point is 100 degrees. For the Fahrenheit scale it is slightly different. The freezing point on the Fahrenheit scale is 32 degrees and the boiling temperature is about 212 degrees. Temperature in Fahrenheit can be converted to Celcius by subtracting 32 degrees and multiplying by (5/9). Then, Celcius can be converted to the Kelvin scale by adding 273.16 to the Celcius temperature. Knowing this, you can determine that absolute zero in Celcius is -273.16 degrees. Kelvin was first thought up in 1848 when Lord Kelvin or William Thomson came up with a system to measure temperature based on the Celcius degree but started zero at “infinite cold.”
In the Absolute Zero Lab, we determined the pressure in psi and the temperature in Celcius of a bulb of gas in different conditions. First, it was in room temperature, then in an ice bath, hot water, and liquid nitrogen. To measure the temperature and pressure, a temperature probe was used and a bulb of air that measured the pressure. Even though common sense would tell you that the temperatures would be different in all of those situations, the pressures differed greatly as well. That’s because the pressure of liquid nitrogen at -196 degrees Celcius is way different than the pressure of the bulb at room temperature. Temperatures taken with the temperature probe need to be changed into Kelvin. With a temperature in Kelvin or a pressure in pascals you can use the Ideal Gas Law (pV=nRT) to find temperature or pressure depending on what you can determine. The many variables stand for pressure, volume in meters cubed, moles, the constant R (8.31J/mol*K), and temperature in Kelvin. The temperatures in the lab varied so drastically, but are an integral part in the study of thermodynamics. The conclusion of the lab was to understand that even with Liquid Nitrogen being extremely cold and other things coming close, finding the absolute zero where no molecules in a substance have any movement whatsoever seems highly unlikely. In fact, fitting with the quantum basics that everything moves at the most basic levels, it is highly unlikely that this can be found. It is more of a theoretical starting point that helps to set a model that we can base our temperature system off of.
In a Molecular speeds lab, the temperature represents the speed of the molecules because heat causes individual molecules to speed up, therefore increasing individual velocities. Therefore, increasing the temperature of a system increases the speed and overall kinetic energy of the entire system. Temperature is also very important when looking at molecular speeds because all of the equations are usually derived from the Ideal Gas Law, which was covered in the Absolute Zero Lab. It is important to know that the molecules and atoms of a gas or other state are always in constant motion. Temperature is a measure of the speed or kinetic energy with which they move. The higher the temperature, the higher the energy associated with those particles. If two different gases have the same temperatures, their molecules individually have the same average kinetic energy. Also, if the temperature of the gas is doubled, the average kinetic energy of the mass of the molecules is also doubled. Therefore, we see that the temperature and average kinetic energy of molecules in a gas are directly proportional and linear. They are directly proportional because as one goes up, the other does too. At higher temperatures, a larger fraction of molecules in a gas are at higher speeds. The distribution of the speeds of molecules at a certain temperature can be graphed. The lines ends up in a normal distribution patterns with a higher fraction of molecules in the middle than at the endpoints(high and low speeds). Because temperature is related to the average kinetic energy, it is also important when looking at the Root mean speed as well. Likewise, if the volume stays the same but the temperature increases the pressure will increase. This occurs because their will end up being more collisions happening between molecules. If pressure stays the same with an increase in temperature, this means that the volume of the gas must increase as well. All of the aforementioned information can be derived by looking at the various situations occurring from altering different variables in the Ideal Gas Law, which is pV=nRT. This equation is the backbone to many of the thermodynamics systems that are important to all aspects of Physics.
Therefore, learn all you can about the various temperature scales and how they affect the world you live in. It may come in handy one day soon. Temperature has everything to do with our everyday lives. It can explain why ice melts or how food cooks.
Until next time,
Brian Jones