Food at fast-food restaurants is kept warm by heat lamps that radiate heat to the food. Many materials can slow the transfer of heat though conduction or convection. Air is an excellent insulator. When you dress in layers during a cold winter day, it is the trapped air between your clothing that acts as an insulator. Radiation can be controlled by smoothness or the color of a surface.
Darker colors absorb radiant heat while lighter colors reflect radiant heat.
Smooth surfaces reflect better than rough surfaces. Inc. All rights reserved.