Temperature

Temperature is related to the average kinetic energy of the particles in a substance. Higher temperature means particles move faster on average.

Two common scales:

• Celsius ($^\circ$C): water freezes at 0, boils at 100
• Kelvin (K): $T = \theta + 273$; absolute zero is 0 K

Temperature is different from thermal energy. A spark has a high temperature but little thermal energy (few particles). A bath of warm water has a lower temperature but much more thermal energy (many particles).