Let us look at the following example to understand heat transfer.
Take a hot cup of tea and keep it at room temperature. Check the temperature of the tea after some time.
Hot cup of tea
Do you think it will be still hot?
No, the hot water turns cold after some time. Things that are hot become colder, and things that are cold become hotter. Heat is transferred from one location to another until both are at the same temperature. When heat energy flows from an object with a higher temperature to an object with a lower temperature, it is called heat transfer.
Heat transfer takes place in three ways,
  • Conduction
  • Convection
  • Radiation
We will discuss all the three process in a detailed manner in the next section.
When a dog holds his tongue out and takes a deep breath, the moisture on his tongue turns to water and evaporates. Because heat is required to convert a liquid to a gas, heat is removed from the dog's tongue. This aids in the cooling of the dog's body.