| English | Absolute temperature scale |
|---|---|
| Bahasa Melayu | Skala suhu mutlak |
| 中文 | 绝对温标 |
Definition
The temperature scale that begins at absolute zero and is measured in kelvin (K), where a change of 1 K equals a change of 1 °C.
In exam terms
The absolute temperature scale (Kelvin scale) is the temperature scale that begins at absolute zero (0 K) and is measured in kelvin (K). A change of 1 K is exactly the same size as a change of 1 °C, so the two scales have equal divisions but different starting points.
To convert, use T/K = θ/°C + 273, so for example 27 °C = 27 + 273 = 300 K. The absolute scale is used in all the gas laws (Charles's law, the pressure law and the general gas law) because it has no negative values, which keeps proportions valid. Example of correct use: the gas is at 300 K, which is the absolute temperature that must go into the pressure law.
Do not confuse it with…
Do not confuse the absolute (Kelvin) scale with the Celsius scale. Their degrees are the same size, but the zero points differ: 0 K equals about −273 °C, and 0 °C equals 273 K. A temperature difference is the same number on both scales, but an actual temperature reading is not.
In Paper 2 this is usually asked as convert this temperature to kelvin or state why absolute temperature is used in the gas laws. Forgetting to add 273 before substituting into a gas-law equation is the most common mistake.
Source: DSKP KSSM Physics Form 4 and 5 (Versi English) (Bahagian Pembangunan Kurikulum (BPK), KPM)