Thermal Concepts
3.1 Thermal Concepts
This lecture covers the foundational concepts of thermal physics for IB Physics.
Key concepts
- Temperature as a measure of average kinetic energy
- The difference between heat and temperature
- Thermal equilibrium and the zeroth law of thermodynamics
Internal energy
Internal energy is the total kinetic and potential energy of all particles in a system. For an ideal gas, internal energy depends only on temperature.
The key equation: KE_avg = (3/2)kT
Where k is Boltzmann’s constant and T is absolute temperature in Kelvin.
Heat capacity
Heat capacity tells us how much energy is needed to raise the temperature of a substance. Specific heat capacity is the heat capacity per unit mass:
Q = mcΔT
Different materials have different specific heat capacities, which explains why water takes longer to heat up than metals.