Heat transfer 3

Conduction

Convection

Radiation

You warm your back using hot water bag

The heat from a hot liquid makes the cup itself hot

metal spoon in a pot becomes hot from the boiling water inside the pot.

Chocolate in your hand will eventually melt as heat is conducted

Ironing clothes

If you touch a light bulb when it is on, your hand will get burned.

Convection can happen in gases or liquids (fluids)

Think about the air. It is a gas. Its particles are quite far apart and can move about freely.

When air is heated, its particles move faster and they move farther apart. The air expands.

Now the air is less dense than the surrounding air and it floats upwards. It carries energy with it.

At the same time, cooler, denser air flows in to replace it.

So convection is the transfer of energy through a fluid when the fluid itself moves.