What’s inside:
Learn about the global patterns that impact earth’s temperature, wind, currents, and climate, known as Global Circulation.
Get this lesson: You can download the full packet here, or read a condensed version of this unit below.
Worksheet: Download just the worksheet, or there’s a copy included in the packet.
Overview:
Global circulation is the worldwide system of winds which transports heat from the tropics to the polar regions. This circulation explains how air and storm systems travel over the Earth’s surface.
In each hemisphere there are three cells (Hadley cell, Ferrel cell, and Polar cell) in which air circulates through the entire depth of the troposphere. These cells greatly influence the climate of a region as they bring weather from their original locations.
In addition, the ocean also has its own system of circulation, known as the “global conveyor belt”. The ocean’s currents are interconnected, powered by winds, tides, Earth’s rotation, sun and water density differences. Surface ocean currents are usually wind driven while deep ocean currents are density-driven. The ocean greatly influences the Earth’s temperature, weather, and climate.
Video resources:
Global circulation: differential heating – A video with helpful graphics describing why parts of the Earth are heated differently.
The hadley, ferrel, and polar cells – Part two of the video above describes the three cells and their functions.
The coriolis effect and winds – The third video from Met Office, the United Kingdom’s weather service, describes the coriolis effect and how winds and jet streams work.
Sample Research Project:
Project: Headwaters’ Global Ocean Circulation Lab
Methods: Use household materials to understand ocean circulation by adding ingredients to a dish filled with water or oil and applying heat. Suggested: begin with the Ocean Circulation lesson before starting the project. Get the full packet here.
Supplies:
- Pyrex baking dish, approximately two quarts in size
- Dried thyme or other dried leaf spices
- Teaspoon measuring spoon
- Measuring cup
- About three cups of vegetable oil or water with a liquid thickener
- Spoon or whisk for stirring
- Two sturdy ceramic coffee mugs, equal in height
- Small candle (This should be much shorter than the coffee mugs.)
- Lighter or matches (Have an adult assist handling the lit candle and lighter or matches.)
- A surface that can handle oily spills, such as the kitchen counter—or towel to protect the surface
NGSS Standards:
MS-ESS2-5; MS-ESS2-6 Earth’s Systems
HS-ESS2-5 Earth’s Systems
SEPs: Analyzing and interpreting data
Constructing Explanations and designing solutions
Scientific knowledge based on empirical evidence
Planning and carrying out investigations
Obtaining, evaluating, and communicating information
CC: Cause and effect
Stability and change
Patterns
Systems and system models
Energy and matter: flows, cycles, and conservation
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