Absolute Zero and the Conquest of Cold  




Topic 5: Cryogenics

"Cryogenics" is a broad term that covers any kind of technology that requires extremely low temperatures. You might be surprised at how many modern technologies require such extreme cold: flash freezing vegetables, high-temperature superconductors in cell phone towers, MRIs, storing liquified natural gas for energy -- just to name a few. (Most of the hands-on activities throughout this section come under the rubric of “cryogenics” as it happens. . .)

The coldest temperature ever recorded on earth was 128.6I F (in Antarctica, measured in 1983), but cryogenics routinely requires temperatures hundreds of degrees below that. To get to temperatures so much colder than those of Mother Nature, these technologies rely on techniques learned over the last century to liquefy gases like hydrogen, helium, nitrogen, and oxygen. These are all things that are a gas at room temperature, but scientists like Heike Kamerlingh Onnes and James Dewar, learned in the late 1800s and the early 1900s how to change their state, and turn them into liquids -- which makes them much colder.

Liquid Nitrogen Show at the Jefferson LaboratoryIt is these liquids that are used to keep different technologies so mind-bogglingly cold. Liquid helium keeps the superconductors in MRIs cold. Liquid nitrogen is used to flash freeze food, as well as to store seeds and medical samples indefinitely. Liquid oxygen is much easier to store than the gaseous version, and is how hospitals store oxygen for their patients.

Additional Resources

Additional liquid nitrogen hands on activities:

More Topics

  • Topic 1: Measuring the Cold - Thermometers
  • Topic 2: Understanding Heat and Energy
  • Topic 3: States of Matter
  • Topic 4: Refrigeration
  • Topic 5: Cryogenics
  • Topic 6: The Quest for Absolute Zero
  • Topic 7: How Animals Survive the Cold
  • Topic 8: Superconductivity
  • Topic 9: Astronomy
  • Topic 10: Spaceflight
  • Topic 11: Agriculture
  • Topic 12: Cold Medicine
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