The History of Cryogenics
Scientists in the 19th Century started experimenting with very cold temperatures. This type of study was called cryogenics. Major experimentation in this area began when scientists such as Michael Faraday began to liquefy gasses. Throughout the century, scientists went on to develop more sophisticated methods to create increasingly colder temperatures - this led to scientists liquefying all the known permanent gasses and finding new properties of solid materials.
A brief history of cryogenics; the discoveries made and the methods used
- 1845 – By this time Michael Faraday had liquefied most of the permanent gasses known at that time except oxygen, hydrogen, nitrogen, carbon monoxide, methane and nitric oxide.
- Method – Immersing the gas in a bath of dry ice and then pressurising it until it liquefied.
- 1877 - Louis Cailletet in France and Raoul Pictet in Switzerland succeeded in creating droplets of liquid air.
- Method – Cailletet dropped the temperature through rapid expansion of the gas. This was achieved by compressing the gas with mercury using a steel and glass apparatus, before draining the mercury away allowing the gas to expand.
- 1898 – James Dewar liquefied hydrogen at the lowest temperature ever achieved at that point, -252.5°C. He went on to solidify it at -258°C.
- Method – Using liquid air at -200°C he cooled the hydrogen before forcing it through a fine nozzle into a vacuum. It liquefied when it escaped from the nozzle.
- 1908 - Heike Kamerlingh Onnes liquefied helium which has the lowest boiling point of any known substance at -268.9°C.
- Method – He created four cooling cycles using different liquefied gasses including oxygen and hydrogen. The helium was cooled more and more at each stage.
- 1911 - Kamerlingh Onnes also discovered that if certain metals are cooled to temperatures not far above absolute zero they lose any resistance to electrical currents. This is called superconductivity and has many applications in the modern world.
Cyrogenic Applications in the 21st Century
MRI scanners widely used in medicine across the world rely on cryogenics to create magnets powerful enough to operate effectively. In scientific research, the Large Hadron Collider at CERN, The European Organisation for Nuclear Research, uses incredibly powerful magnets kept at very low temperatures to accelerate particles. Cryogenic liquids are also used a great deal in space exploration.
Cryogenic experimentation has come an incredibly long way over the past 150 years but it is still ongoing and continuing to make important discoveries. AML makes stepper motors and other equipment which can be used to conduct experiments with and using cryogenic materials. Call 01903 884141 or email firstname.lastname@example.org to find out what they can do for you and your research.