Absolute Zero and Low Temperature
At 0 K particles have minimum energy.
About this topic
Absolute zero, 0 K or −273.15 °C, is the lowest possible temperature, where particles have their minimum energy and gas pressure would drop to zero. It can be approached but never reached.
Near it, strange effects appear: superconductors conduct electricity without resistance, helium becomes a superfluid that flows without friction and climbs container walls, and atoms can merge into a Bose-Einstein condensate behaving as one quantum wave. Laboratories have cooled atoms to billionths of a kelvin using lasers and magnetic traps.
Worked example: if you extrapolate a graph of gas volume against temperature for a fixed pressure, the lines for all gases cross the axis at about −273 °C, which is how the idea of absolute zero arose. Liquid nitrogen at 77 K is used to cool superconducting magnets and freeze samples, while liquid helium at 4 K cools MRI magnets.
The third law of thermodynamics says that reaching absolute zero in a finite number of steps is impossible. Real gases liquefy before then, so the ideal gas model does not hold. A misconception is that atoms stop completely; quantum mechanics keeps a small zero-point motion. Deep space is not at 0 K but about 2.7 K, the afterglow of the Big Bang.
Key ideas
- −273.15 °C
- Gas volume extrapolates to zero
- Superconductors appear near it
Quick check
Use cases: where Absolute Zero and Low Temperature helps
- Homework: review the key idea behind Absolute Zero and Low Temperature before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Absolute Zero and Low Temperature without notes.
- Visual learning: play with the interactive lab to see how Absolute Zero and Low Temperature changes when you adjust its inputs.
- Teaching a friend: explain Absolute Zero and Low Temperature in your own words, then compare your version with the key ideas.
The same laws describe car crashes, sports, satellites and everyday machines.
Frequently asked questions
What is Absolute Zero and Low Temperature?
At 0 K particles have minimum energy.
What will I learn in Absolute Zero and Low Temperature?
−273.15 °C. Gas volume extrapolates to zero. Superconductors appear near it.
Is Absolute Zero and Low Temperature part of Physics?
Yes. It is one of 150 Physics topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Absolute Zero and Low Temperature lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Absolute Zero and Low Temperature?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
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