Science
What is Temperature?
Temperature is a measure of how hot or cold something is — specifically, the average energy of the particles moving inside it. The faster its particles move, the higher its temperature. It's measured in degrees Celsius, Fahrenheit, or kelvin.
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Watch a 2-minute lesson with voice + animation that explains temperature.
Key things to understand
- 1Temperature reflects the average kinetic energy of an object's particles.
- 2Faster-moving particles mean a higher temperature.
- 3It's measured in Celsius (°C), Fahrenheit (°F), or kelvin (K).
- 4It differs from heat: temperature is how hot something is; heat is the energy that flows between things.
- 5The lowest possible temperature is absolute zero (−273.15°C), where particle motion is minimal.
Frequently asked questions
- What's the difference between temperature and heat?
- Temperature is how hot or cold something is — the average energy of its particles. Heat is the total thermal energy that flows from a hotter object to a cooler one. They're related but not the same.
- What is absolute zero?
- Absolute zero (−273.15°C, or 0 kelvin) is the lowest possible temperature, where particles have the least possible motion. It can be approached but never fully reached.
- Why are there different temperature scales?
- Celsius and Fahrenheit were set using different reference points; kelvin starts at absolute zero and is used in science for its simplicity.