Heat is a form of energy that is transferred between objects or systems due to a difference in temperature.
Heat is measured in units of energy, such as joules or calories. It can also be measured using a thermometer, which measures the temperature of an object or system.
Heat can be transferred through conduction, convection, and radiation. Conduction is the transfer of heat through direct contact between objects, convection is the transfer of heat through the movement of fluids, and radiation is the transfer of heat through electromagnetic waves.
Heat can cause changes in the physical properties of matter, such as changing its state from solid to liquid or gas. It can also cause objects to expand or contract.
Heat and temperature are related but not the same. Temperature is a measure of the average kinetic energy of particles in a substance, while heat is the total energy contained in a substance. When heat is added to a substance, its temperature usually increases.