Heat and temperature________________________________________________________________9. Heat transfer. Convection
Figure 7.14Do you see the water bubbling in this pot? The water is boiling hot. How does all of the water in the pot get hot when it is heated only from the bottom by the gas flame? The answer is convection. Convection is the transfer of thermal energy by particles moving through a fluid (either a gas or a liquid). Thermal energy is the total kinetic energy of moving particles of matter, and the transfer of thermal energy is called heat. Convection is one of three ways that thermal energy can be transferred (the other ways are conduction and thermal radiation). Thermal energy is always transferred from matter with a higher temperature to matter with a lower temperature.