2. Convections currents is the upward movement of
warm air and the downward movement of cool
air. Heat is transferred mostly by convection
within the troposphere.
3.
4. The mantle is made
of much denser,
thicker material,
because
of this, the plates
"float" on it like oil
floats
on
water..
5. Convection currents are caused by the very hot
material at the deepest part of the mantle
rising, then cooling, then sinking again and then
heating, rising and repeating the cycle over and
over.
Convection takes place when heated molecules
move from one place to another, taking the heat
with them. Convection is common in both the
atmosphere as well as in the oceans.
6. The pot of water shows how convection currents
move. Its basically a cycle of warm and cool water
going around and around.
As the cooler water
descends and moves
downward, the
Warmer water rises.
7. Heated air in our atmosphere expands, becoming
less dense. Because it is less dense, it rises upward.
Cooler air rushes in to replace the air that lifted up.
8. Convection also takes place within the Sun. Large
amounts of hot gas rise up towards the surface of
the Sun. As they do so, they become cooler and
begin to fall back down towards the center of the
Sun. As they do so, they again heat up and begin
rising again, over and over.
