Cooler and denser air sinks and a convection current begins. This phenomenon occurs in liquid also. A convection oven blows heat around and causes food to cook faster. Waves of energy can travel through space, heating objects they strike. Radiation is used for broiling, grilling, and toasting.
Radiation is also one of the ways ovens cook.
Use dark, dull baking pans to absorb radiant heat and shiny ones to reflect heat and decrease browning. Use of foil to brown or not. Glass is a good conductor of radiant waves. If we put moisture under pressure in a pressure cooker, we can increase temperature in the pressure pan. This allows moist heat cooking to go above boiling point and therefore cook food faster.