Thermal Physics

Temperature

Measures how hot or cold something is, related to the average kinetic energy of particles.

Heat

Energy transferred between objects due to a temperature difference, flowing from hotter to colder objects.

Internal Energy

Total energy of all particles in a substance, including kinetic and potential energy.

Conduction

Heat transfer through direct contact of particles.

Convection

Heat transfer through moving fluids (liquids or gases).

Radiation

Heat transfer through electromagnetic waves, like sunlight.

Solid

A state of matter where particles are tightly packed and vibrate in fixed positions.

Liquid

A state of matter where particles are close but can slide past each other.

Gas

A state of matter where particles are far apart and move freely.

Melting

The process of changing from solid to liquid.

Boiling/Evaporation

The process of changing from liquid to gas.

Freezing

The process of changing from liquid to solid.

Condensation

The process of changing from gas to liquid.

Sublimation

The process of changing from solid to gas without becoming liquid.

Zeroth Law of Thermodynamics

If two objects are in thermal equilibrium with a third, they are also in equilibrium with each other.

First Law of Thermodynamics

Energy is conserved; heat added to a system equals the increase in internal energy plus work done.

Second Law of Thermodynamics

Heat flows naturally from hot to cold, and entropy always increases in a closed system.

Third Law of Thermodynamics

As temperature approaches absolute zero, particle motion nearly stops and entropy becomes minimal.

Heat Capacity

The amount of heat energy needed to raise the temperature of an object.

Thermal Equilibrium

A condition where two objects in thermal contact no longer exchange heat, indicating they are at the same temperature.

Specific Heat Capacity

The amount of heat required to raise the temperature of one gram of a substance by one degree Celsius.

Latent Heat

The heat energy required for a phase change of a substance without a change in temperature.

Thermal Conductivity

A measure of how well a material conducts heat; higher values indicate better heat conduction.

Phase Diagram

A chart showing the states of matter of a substance at different temperatures and pressures.

Thermal Expansion

The increase in volume of a substance when its temperature increases.

Phase Change

The transition of a substance from one state of matter to another, such as melting or boiling.

Thermal Insulator

A material that resists the flow of heat, preventing heat transfer.

Thermal Conductor

A material that allows heat to pass through it easily.

Heat Transfer

The movement of thermal energy from one object or substance to another.

Specific Heat

The amount of heat required to raise the temperature of a substance by one degree Celsius.

Absolute Zero

The theoretical temperature at which a system has minimum thermal energy, defined as 0 Kelvin.

Enthalpy

The total heat content of a system, often used in thermodynamic calculations.

Calorimetry

The measurement of heat transfer in physical and chemical processes.

Latent Heat of Vaporization

The amount of heat energy required to convert a unit mass of a substance from liquid to gas at constant temperature.

Thermodynamics

The branch of physics that deals with the relationships between heat and other forms of energy.

Carnot Cycle

A theoretical thermodynamic cycle that provides the maximum efficiency limit of heat engines.

Heat Engine

A device that converts heat into mechanical work through a cyclic process.

Refrigerator

A device that removes heat from a low-temperature reservoir and transfers it to a higher temperature reservoir.

Entropy

A measure of the disorder or randomness in a system, often associated with energy dispersal.

Heat Exchanger

A device that transfers heat between two or more fluids without mixing them.

Thermal Equilibrium

A state where two systems exchange no heat because they are at the same temperature.

Work

The energy transferred to or from an object via a force acting on it over a distance.

Thermodynamic Properties

Physical quantities such as temperature, pressure, volume, and internal energy that characterize the state of a system.

Phase Transition

The transformation from one phase of matter to another, such as solid to liquid or liquid to gas.

Superheating

Heating a liquid beyond its boiling point without vaporization.

Undercooling

Cooling a liquid below its freezing point without it becoming solid.

Caloric Theory

An obsolete theory that treated heat as a fluid called caloric.

Temperature Gradient

The rate of temperature change in a given direction; it indicates heat flow direction.