Page 170 - Science Coursebook

11.5 Convection

Conduction is just one way in which energy can be
transferred from a hotter place to a colder place. Here is
another.

The eagle in the photograph does not have to flap its wings

to stay up in the air. It has found a place where warm air is
rising. The rising air supports the eagle.
Warm air rising like this is called a convection current.
The rising air carries energy from the warm ground up into
the cold atmosphere. The eagle is soaring on warm, rising air.

Convection at home
When it is cold, you may use a heater to warm the room you are in.

• The heater transfers energy to the air next to it.
• This warm air rises.
• Cold air flows in to replace the warm air.

In this way, a convection current is set up in the room, and this spreads the energy
from the heater all round the room.

A convection current transfers energy from the heater to the rest of the room.

Question
A+I 1 If you go to the beach on a hot day, you may notice that a cool breeze blows
from the sea onto the land. Explain why this breeze happens.

168 11 Energy

A+E