Absolute Zero
Definition and meaning of Absolute Zero in chemistry.
Absolute zero is the lowest possible temperature, at which a substance has minimum thermal energy and particle motion falls to its lowest level. It is defined as 0 kelvin, equal to −273.15 °C or −459.67 °F.
In more detail
Absolute zero is the starting point of the Kelvin temperature scale. According to the third law of thermodynamics it can be approached ever more closely but never actually reached. If an ideal gas could be cooled to absolute zero, its volume would extrapolate to zero, a relationship used historically to estimate the value of absolute zero.
Key facts
| Value | 0 K = −273.15 °C = −459.67 °F |
|---|---|
| Meaning | Minimum thermal energy |
| Governed by | Third law of thermodynamics |
| Field | Physical chemistry |
Scientists have cooled atoms to within a tiny fraction of a degree above absolute zero, but never all the way to 0 K.
Frequently asked questions
Can absolute zero be reached?
No. The third law of thermodynamics states that absolute zero can be approached but never fully reached; only temperatures extremely close to it have been achieved.
What is absolute zero in Celsius and Fahrenheit?
Absolute zero is −273.15 °C, which is −459.67 °F.