Oceans, Winds and Climate
- Earth & Space
- Ages 11–14 · Grades 6–8
What you’ll find out
- Uneven heating of a round Earth drives convection cells and global winds.
- Earth’s rotation deflects moving air and water (the Coriolis effect).
- Ocean currents redistribute heat and strongly affect regional climates.
No sign-up and no real names. In the lesson you check your understanding as you read, and practise until it sticks.
Uneven heating drives the winds
The Sun heats Earth unevenly. Near the equator, sunlight strikes the surface almost straight on, concentrating its energy, while near the poles it arrives at a low angle and is spread over a larger area. Warm air near the equator rises, and cool air sinks elsewhere, setting up huge loops of moving air called convection cells. Earth’s rotation bends these moving air streams, producing steady global winds such as the trade winds, which sailors once relied on to cross the oceans.
Ocean currents move heat
The oceans are also on the move. Winds drag the surface water along, creating ocean currents that flow like rivers through the sea. Warm currents carry heat away from the tropics, while cold currents bring cool water from polar regions. The Gulf Stream, a powerful warm current, flows from the Caribbean across the Atlantic, helping to keep western Europe’s winters surprisingly mild. Cold currents, by contrast, can make nearby coasts cool and dry, as in parts of South America and southern Africa.
Curriculum links: NGSS MS-ESS2-6 · Cambridge Lower Secondary Stages 7–9: Earth and space · NCERT Science, Classes 6–8