Heat in physics refers to the transfer of thermal energy from one object to another due to a temperature difference.
It involves the transfer of thermal energy from a hotter object to a cooler one. Thermal energy is the form of energy being transferred.
Examples include sunlight warming the Earth, a burning candle emitting heat energy, and thermal energy in particles within a substance.
Temperature is not just about how hot or cold something feels; it's a measure of the average kinetic energy of particles in an object.
Temperature is measured using a thermometer, which operates based on thermal expansion.
Thermal energy can be transferred through conduction (direct contact), convection (movement of liquids or gases), and radiation (electromagnetic waves).
Matter exists in three states: solid, liquid, and gas. Heat can cause changes between these states (physical changes) or initiate chemical reactions (chemical changes).