1. Convection Currents:
A Very Hot Topic

2. Convection occurs because heat rises, and as it rises it cools
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!

3. Convection currents can occur in liquids or gases
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.

4. 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.

5. 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.

6. The heat source is the sun!

7. The greatest heat is at the equator, of course, where it all begins
The greatest heat is at the equator, of course, where it all begins. The hot air rises and starts the convection currents moving.

8. These get other currents turning, and as the Earth spins, the result is the major wind patterns of the Earth.

9. A smaller example of convection happens along coasts, and is the reason we have such nice summer temperatures here on Martha’s Vineyard!

10. 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.

11. Explain what is causing the air to move in these convection currents
Explain what is causing the air to move in these convection currents. And why is it different at night and day?