Air is a good insulator because it is a gaseous substance, therefore its spread-out molecular configure resists heat transfer to some degree. This small space of air between the two layers of glass reduces the ability of heat transfer via convection.

Solids conduct heat better than liquids, which are in turn better conductors than gases. The particles in a solid are most tightly bond and their positions are more or less fixed relative to each other (Fig. 5a). The force between adjacent particles is strong, making heat transfer by collision the most efficient.

Air may be a bad conductor of heat because its molecules aren’t in continuous contact with one another. Air molecules are too far to disperse heat to at least one another efficiently. Heat is transferred or conducted by molecules and atoms that are very closely bonded together and vibrating at high frequency.

The Three Mechanisms of Heat Transfer: Conduction, Convection, and Radiation.

Everyday Examples of Heat or Thermal Conduction As the pad heats up, it transfers heat to the part of your body that it is in contact with. The heat from a hot liquid makes the cup itself hot. If you grab a cup that has hot coffee, tea or broth in it, the cup itself will be hot and your hands will feel it.

Everyday Examples of Heat or Thermal Conduction

• After a car is turned on, the engine becomes hot.
• A radiator is a good example of conduction.
• You can warm your back muscles with a heating pad.
• Roasting wieners over a campfire is fun until the heat from the fire is conducted up the coat hanger to your hand.

The best example of thermal conduction is an egg cooking in a frying pan.

Heat is transferred by conduction, convection, and radiation. Conduction is heat transfer by direct contact, like frying an egg. Convection is heat transfer by the movement of gases or liquids, like most home furnaces, clothes dryers, or car heaters.

convection

conduction