Thermal physics key terms

temperature

A measure of the average kinetic energy of the particles in a substance, typically measured in degrees Celsius (°C) or Kelvin (K).

internal energy

The total energy contained within a system, including both the kinetic energy of particles and the potential energy of interactions between them.

specific heat capacity

The amount of energy required to raise the temperature of 1 kg of a substance by 1 °C.

thermal equilibrium

The state in which two objects in thermal contact no longer exchange energy, resulting in equal temperatures.

thermal equilibrium

The state in which two bodies in thermal contact no longer exchange energy, as they reach the same temperature.

energy transfer direction

The movement of thermal energy from a region of higher temperature to a region of lower temperature until thermal equilibrium is achieved.

heating data

Data collected that shows the temperature changes in a substance as it absorbs heat. In Thermal physics, use this term with the exact equation, unit, motion model, or thermal process it belongs to, rather than as a generic label.

cooling data

Data collected that shows the temperature changes in a substance as it loses heat. In Thermal physics, use this term with the exact equation, unit, motion model, or thermal process it belongs to, rather than as a generic label.

Ideal gas constant

The universal constant R that relates pressure, volume, temperature and amount of an ideal gas in the equation pV = nRT.

Moles of gas

The amount of substance n, measured in moles, that appears in the ideal gas equation pV = nRT and represents the number of gas molecules present.

Temperature Conversion

The process of converting temperature from degrees Celsius to Kelvin using the formula K = °C + 273.15.

Kelvin Scale

A temperature scale where 0 K is absolute zero, and each unit is equivalent to one degree Celsius.

Pressure-Volume Relationship

As the volume of a gas decreases, the pressure increases, demonstrating an inverse relationship as described by Boyle's Law.

Pressure-Temperature Relationship

At constant volume, an increase in temperature results in an increase in pressure, illustrating the direct relationship between these two variables in gas behavior.

Boyle's Law

The pressure of a given mass of gas is inversely proportional to its volume at constant temperature.

Pressure-Volume Relationship

In an ideal gas, when the volume decreases, the pressure increases, provided the temperature remains constant.

Gas Pressure

The force exerted by gas molecules colliding with the walls of a container per unit area.

Molecular Collisions

Interactions between gas molecules that result in changes in momentum and contribute to gas pressure.

absolute temperature

The temperature measured on the Kelvin scale, where 0 K is absolute zero, the point at which molecular motion ceases.

molecular kinetic energy

The energy possessed by molecules due to their motion, directly proportional to the absolute temperature of the gas.

Kinetic Theory

A model that explains the behavior of gases in terms of particles in constant motion, linking temperature to molecular kinetic energy.

Ideal Gas Law

A fundamental equation in thermodynamics, represented as pV = nRT, relating pressure, volume, temperature, and the number of moles of a gas.

Ideal Gas Model Assumptions

The ideal gas model assumes that gas particles have negligible volume, no intermolecular forces, and that they undergo perfectly elastic collisions.

Molecular Collisions

Molecular collisions in gases are assumed to be elastic, meaning that kinetic energy is conserved during the collisions between gas particles.