how do plates move

Question 1

convection currents

Answer 1

high temperatures in the inner core heat the magma above it
hot magma rises because it is less dense as it reaches the crust it cools
the magma then sinks back down to the inner core (this is called a CONVECTION CURRENT)

Question 2

ridge push

Answer 2

the magma moves the plates apart due to convection currents
the magma forces through the crust
the land is thrust upwards
due to gravity old land slides away from the ridge
RIDGE PUSH

Question 3

slab pull

Answer 3

crust is pulled down into the mantle due to gravity
this extra crust melts due to high temperatures forming new magma
SLAB PULL