Transcript Convection Currents

Convection Currents:
A Very Hot Topic
Convection occurs because heat rises, and as it rises it cools.
Cooler things then sink back down, being replaced by something
warmer behind it. And around and around it goes!
Convection currents can occur in liquids or gases. Common
examples are in heating water on a stove, or the heat in a room.
All you need is a heat source to drive it.
At a bigger level, geologists believe convection is what makes
tectonic plates move! There is clearly a tremendous amount of
heat inside the Earth (just look at volcanoes), which could drive the
convection in the mantle.
Heat convection is also responsible for the
major wind and weather patterns of the Earth.
Think about that, and try to explain what the heat
source might be, and how it affects Earth’s winds and
weather patterns.
The heat source is the sun!
The greatest heat is at the equator, of course, where it
all begins. The hot air rises and starts the convection
currents moving.
These get other currents turning, and as the Earth
spins, the result is the major wind patterns of the Earth.
A smaller example of convection happens along coasts,
and is the reason we have such nice summer
temperatures here on Martha’s Vineyard!
Coastal places (like MV) have cooler days and cooler
nights because of this convection.
- Again, the heat source is the sun, which can warm the
land or the sea, and cause two things to happen.
-During the day we have cool onshore wind called sea
breeze.
-At night we have cool offshore wind called land breeze.
Explain what is causing the air to move in these convection
currents. And why is it different at night and day?