• Heat is a form of energy which tends to move from one point to another.
• Heat is a form of energy that flows from a hot area to a cold area or region, e.g. heat flows from the fire through the kettle into the water, from the sun through the atmosphere to us, etc.
• Heat flows through solids, liquids and gases by conduction, convection, and radiation respectively.

Heat Transfer Modes (Photo Credit: HVAC Palace)

• Conduction
  • Conduction is a process of heat transfer from one particle to another in a solid, e.g. metals.

  Applications

  • Heat conduction is applied in cooking with metal pots; the metal pot conducts heat from the fire used for cooking to the food that is being cooked in the pot.

• Convection
  • Convection is the process by which heat is transferred form one place to another through liquid or gas medium.

  Applications

  • Air moving around the room in a characteristic path.

• Radiation
  • Radiation is a method of heat transfer which does not include any medium between the source of the heat and the object receiving the heat.

  Applications

  • We warm ourselves by staying near a fire.
  • We dry clothes in the sun.