Convection

1
Convection

• By the end of this presentation, you should be
  able to
• Explain what convection is.
• Describe what happened to a liquid or a gas when
  it is heated so that convection currents are
  created.

2
Explaining convection
Convection is the movement of heat from a hotter
region to a cooler region with movement of the
substance as a whole. This is the way heat moves
through liquids and gases.
- a water molecule. The water at
the bottom expands as it heats up before the
water above. It then rises, then cools, and sinks
again.
heat
3
The paragraph below relates to convection . Copy
it and fill in the blanks.
Pick from these words Currents liquid
expands hotter cooler gas rises
falls dense

• Convection is the movement of heat through a
  ________ or a _____ . The heat energy is
  transferred from a ________ area to a ________
  area. When the fluid is heated it ________. It
  then becomes less _______ than its surroundings
  so it _______. Cooler liquid or gas then _______
  to take its place. Convection __________ are set
  up in this way.

liquid
gas
hotter
cooler
expands
dense
rises
falls
currents