1. The earth’s core heats the magma above, causing it to rise slowly upwards towards the crust.
Plates
Mantle Magma
2 3
Convection current
1 Core Convection currents
Convection current
3
2. As the magma rises, it then begins to cool.
3. This cooling results in the magma becoming heavier and sinking back down towards the core.
4. The cycle continuously repeats and causes a circular movement of magma (convection currents) in the mantle.
5. These convection currents cause the plates to move very slowly. The plates are dragged apart (separate), are pushed together (collide) or slide past each other.
Wood blocks separating
Water
Convection current
Convection current
Plates
Imagine heating water in a pot on the stove. As the water comes to the boil, the wooden blocks move apart due to the convection currents moving.
Mantle Magma
Convection current
Core Stove
Managing information and thinking:
Look back at figure 1 (p. 2). Thinking about how convection currents cause plates to move, can you identify two continents that were pulled apart due to convection currents in the mantle? Write them down and check your answer with the person next to you.
