Definition of Cryogenics

Cryogenics is the study of extremely low temperatures and of how those materials behave when they get there. The cryogenic temperature range has been defined as from -150 degrees, Celsius to -273 degrees Celsius, or absolute zero. Cryogenic temperatures are usually described in the absolute or Kelvin temperature scale, in which absolute zero is written as 0K, without a degree sign. The temperature at which molecular motion comes to a stop is theoretically possible to ceasing completely. This leads to the next topic, the Kelvin scale.

Kelvin Scale

At very low temperatures, molecules come to a complete halt and behave very differently than when they were in a warmer state. These temperatures are written out in the Kelvin scale, as opposed to the regular degrees. It is especially designed to have the temperature at which atoms stop moving be 0K. Therefore the concept of absolute zero is easier to calculate and comprehend. The conversion equation from Celsius to Kelvin is to just add 273 to whatever Celsius equation you have.

Kinetic Molecular Theory

The Kinetic Molecular Theory explains the forces between molecules and the energy that they possess. Matter is composed of small particles (molecules). The measure of space that the molecules occupy (volume) is derived from the space inbetween the molecules and not the space the molecules contain themselves. The following list below is of the five postulates of this theory.

1. A gas consists of a collection of small particles traveling in straight-line motion and obeying Newton's Laws.
2. The molecules in a gas occupy no volume (that is, they are points).
3. Collisions between molecules are perfectly elastic (that is, no energy is gained or lost during the collision).
4. There are no attractive or repulsive forces between the molecules.
5. The average kinetic energy of a molecule is 3kT/2. (T is the absolute temperature and k is the Boltzmann constant.)

Because cryogenic temperatures do not occur naturally, scientists had to come up with certain methods in order to figure out how exactly that would work. That is, how on earth they could get temperatures so low that the atoms would actually almost stop moving (almost because even after all, they have only gotten about a millionth or so away from that theoretical zero Kelvin temperature.) This theory was instrumental in understanding how to do that. By molecules slowing down, the temperature goes down. By knowing this,

scientists were able to come up with many way in which to cool things down cryogenically

because they knew that by slowing down the particles in a container, it would get colder. By

knowing the certain speed of molecules and their resistance, scientists were able to discover

which molecules were able to cool down so much so that they could make a cryogenic fluid. Examples

of these molecules include liquid Nitrogen, Helium, and Oxygen.

Cryogenics Methods of Cooling

The following four things listed are four of the methods of cryogenic cooling.

1. Evaporative Cooling

2. Joule-Thompson Effect

3. Heat Conduction

4. Adiabatic Demagnitization

1. Evaporative Cooling

• Used when atoms are in a gaseous state, they have more energy than they do when they are in a gaseous state
• When a liquid evaporates, atoms or molecules at the surface acquire enough energy from the surrounding liquid to enter the gaseous state. The remaining liquid has relatively less energy,so its temperature drops.
• By encouraging the process of evaporation, the temperature of liquids can be lowered.
• It can be used to reduce the temperature of liquid nitrogen to its freezing point, or to lower the temperature of liquid helium to approximately 1K

Joule-Thompson Effect and Heat Conduction

• Joule-Thompson effect also called cooling by rapid expansion
• Even though they are different, they are used in conjunction with one another
• Example: Kamerlingh Onnes
• First Step: When he first liquified helium, he cooled the gas through conduction to  successively lower temperatures
• Second Step: Brought it into contact with three successively colder liquids: Oxygen,  Nitrogen, and Hydrogen
• Last Step: Used a Joule-Thompson valve to expand the cold gas and produce a mixture of gas and liquid droplets

Adiabatic Demagnatization

• Uses salts that are paramagnetic in order to absorb the heat from whatever you are trying to cool
• With this method, it is possible to reach a temperature of that is a thousandth above 0K.
• Paramagnetic magnets are made up of a bunch of tiny magnets that are called magnetic moments
• When the alt is placed in a magnetic field by turning on a nearby electromagnet, the north poles of each magnetic moment are repelled by the north pole of the applied magnetic field, so many of the moments align in the same way, that is, opposite to the applied field. This process decreases the entropy of the system.

Uses of Cryogenics

• Dipin Dots
• This is a specific type of ice cream that is made up of tiny beads and taste just like regular ice cream.
• The only difference is that it is frozen using liquid nitrogen instead of a freezer. Liquid Nitrogen is a cryogenic fluid.
• The Liquid Nitrogen gives it its unique bead shape and texture.

• Space Shuttle Columbia
• The space shuttle Columbia was lauched in 1982 with the assistance of liquid oxygen and nitrogen propellants. 
• These things were used as a kind of fluid to propel the rocket.
• Large Hadron Collider
• Particle accelerators use cryogenics in order to create superconducting magnets, electromagnets to be more specific.
• Such low temperatures are needed because in normal electromagnets, the particles are moving so fast in the current, the electromagnets that are used could be melted.
• Liquid He is used to cool the cale in which the current is flowing. The temperature of this cable is kept at about 4K.
• This way, the current can flow faster, with much less heat resistance. The lower the temperature is, the lower the resistance is and the higher the current will be.
• This will create less energy loss and a more effective experiment.

• Cryomedicine
• Liquid Nitrogen can be used to remove warts and other things of that kind fairly painlessly.
• Eggs and sperm are cryogenically stored.
• Cryogenics can be used to freeze surgical tools to create less bleeding during surgury.
• Cryotubes are viles in which tiny beads are placed. These tiny beads have little holes in them where bacteria is placed. The tubes are then placed in liquid nitrogen, a cryogenic fluid.

• Cryogenic Body Freezing
• This process involves freezing a body after death, hoping that someday, they will eventually be able to be brought back to life. 
• Only about a hundred people have done this over the past 20 or so years due to controversy over whether it meets their religious practices, whether or not it is possible, and moral and ethical reasons.

Uses of Cryogenics

• Dipin Dots
• This is a specific type of ice cream that is made up of tiny beads and taste just like regular ice cream.
• The only difference is that it is frozen using liquid nitrogen instead of a freezer. Liquid Nitrogen is a cryogenic fluid.
• The Liquid Nitrogen gives it its unique bead shape and texture.

• Space Shuttle Columbia
• The space shuttle Columbia was lauched in 1982 with the assistance of liquid oxygen and nitrogen propellants. 
• These things were used as a kind of fluid to propel the rocket.
• Large Hadron Collider
• Particle accelerators use cryogenics in order to create superconducting magnets, electromagnets to be more specific.
• Such low temperatures are needed because in normal electromagnets, the particles are moving so fast in the current, the electromagnets that are used could be melted.
• Liquid He is used to cool the cale in which the current is flowing. The temperature of this cable is kept at about 4K.
• This way, the current can flow faster, with much less heat resistance. The lower the temperature is, the lower the resistance is and the higher the current will be.
• This will create less energy loss and a more effective experiment.

• Cryomedicine
• Liquid Nitrogen can be used to remove warts and other things of that kind fairly painlessly.
• Eggs and sperm are cryogenically stored.
• Cryogenics can be used to freeze surgical tools to create less bleeding during surgury.
• Cryotubes are viles in which tiny beads are placed. These tiny beads have little holes in them where bacteria is placed. The tubes are then placed in liquid nitrogen, a cryogenic fluid.

• Cryogenic Body Freezing
• This process involves freezing a body after death, hoping that someday, they will eventually be able to be brought back to life. 
• Only about a hundred people have done this over the past 20 or so years due to controversy over whether it meets their religious practices, whether or not it is possible, and moral and ethical reasons.

Cryogenics Methods of Cooling

The following four things listed are four of the methods of cryogenic cooling.

1. Evaporative Cooling

2. Joule-Thompson Effect

3. Heat Conduction

4. Adiabatic Demagnitization

1. Evaporative Cooling

• Used when atoms are in a gaseous state, they have more energy than they do when they are in a gaseous state
• When a liquid evaporates, atoms or molecules at the surface acquire enough energy from the surrounding liquid to enter the gaseous state. The remaining liquid has relatively less energy,so its temperature drops.
• By encouraging the process of evaporation, the temperature of liquids can be lowered.
• It can be used to reduce the temperature of liquid nitrogen to its freezing point, or to lower the temperature of liquid helium to approximately 1K

Joule-Thompson Effect and Heat Conduction

• Joule-Thompson effect also called cooling by rapid expansion
• Even though they are different, they are used in conjunction with one another
• Example: Kamerlingh Onnes
• First Step: When he first liquified helium, he cooled the gas through conduction to successively lower temperatures
• Second Step: Brought it into contact with three successively colder liquids: Oxygen, Nitrogen, and Hydrogen
• Last Step: Used a Joule-Thompson valve to expand the cold gas and produce a mixture of gas and liquid droplets

Adiabatic Demagnatization

• Uses salts that are paramagnetic in order to absorb the heat from whatever you are trying to cool
• With this method, it is possible to reach a temperature of that is a thousandth above 0K.
• Paramagnetic magnets are made up of a bunch of tiny magnets that are called magnetic moments
• When the alt is placed in a magnetic field by turning on a nearby electromagnet, the north poles of each magnetic moment are repelled by the north pole of the applied magnetic field, so many of the moments align in the same way, that is, opposite to the applied field. This process decreases the entropy of the system.

Definition of Cryogenics

Cryogenics is the study of extremely low temperatures and of how those materials behave when they get there. The cryogenic temperature range has been defined as from -150 degrees, Celsius to -273 degrees Celsius, or absolute zero. Cryogenic temperatures are usually described in the absolute or Kelvin temperature scale, in which absolute zero is written as 0K, without a degree sign. The temperature at which molecular motion comes to a stop is theoretically possible to ceasing completely. This leads to the next topic, the Kelvin scale.

Kelvin Scale

At very low temperatures, molecules come to a complete halt and behave very differently than when they were in a warmer state. These temperatures are written out in the Kelvin scale, as opposed to the regular degrees. It is especially designed to have the temperature at which atoms stop moving be 0K. Therefore the concept of absolute zero is easier to calculate and comprehend. The conversion equation from Celsius to Kelvin is to just add 273 to whatever Celsius equation you have.

Kinetic Molecular Theory

The Kinetic Molecular Theory explains the forces between molecules and the energy that they possess. Matter is composed of small particles (molecules). The measure of space that the molecules occupy (volume) is derived from the space inbetween the molecules and not the space the molecules contain themselves. The following list below is of the five postulates of this theory.

1. A gas consists of a collection of small particles traveling in straight-line motion and obeying Newton's Laws.
2. The molecules in a gas occupy no volume (that is, they are points).
3. Collisions between molecules are perfectly elastic (that is, no energy is gained or lost during the collision).
4. There are no attractive or repulsive forces between the molecules.
5. The average kinetic energy of a molecule is 3kT/2. (T is the absolute temperature and k is the Boltzmann constant.)

Because cryogenic temperatures do not occur naturally, scientists had to come up with certain methods in order to figure out how exactly that would work. That is, how on earth they could get temperatures so low that the atoms would actually almost stop moving (almost because even after all, they have only gotten about a millionth or so away from that theoretical zero Kelvin temperature.) This theory was instrumental in understanding how to do that. By molecules slowing down, the temperature goes down. By knowing this,

scientists were able to come up with many way in which to cool things down cryogenically

because they knew that by slowing down the particles in a container, it would get colder. By

knowing the certain speed of molecules and their resistance, scientists were able to discover

which molecules were able to cool down so much so that they could make a cryogenic fluid. Examples

of these molecules include liquid Nitrogen, Helium, and Oxygen.