Wind

Wind

Middle School

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Learning Objectives

• Define wind and how it is caused by differences in air pressure.

• Explain the differences between local winds like land breezes and sea breezes.

• Describe how the Coriolis effect influences the direction of winds on Earth.

• Identify the three major global wind belts: trade winds, westerlies, and polar easterlies.

Key Vocabulary

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Wind

Wind is moving air caused by different temperatures and air pressure from the uneven heating of Earth.

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Sea Breeze

A cool wind that blows from the sea to the land during the day when land is warmer.

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Coriolis Effect

The curving of winds and ocean currents that is caused by the Earth spinning on its axis.

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Trade Winds

Winds that blow from 30° latitude toward the equator and curve to the west.

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Westerlies

Winds from 30° to 60° latitude that blow from the west to the east toward the poles.

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What Causes Wind?

• Wind is air moving from a high-pressure area to a low-pressure area.

• The greater the pressure difference, the faster the wind will blow.

• Uneven heating of Earth’s surface causes these pressure differences to form.

• Warm air rises, creating low pressure, while cool air sinks, creating high pressure.

Multiple Choice

What is the primary cause of differences in air pressure that create wind?

• The uneven heating of the Earth's surface

• The gravitational pull of the moon

• The Earth's magnetic field

• The rotation of the Earth

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Local Winds

Sea Breeze

• This type of local wind occurs during the day when the sun is out.

• Land heats up much faster than the water in the sea, creating warmer air over the land.

• Cooler, denser air from over the sea moves inland to replace the rising warm air.

Land Breeze

• This local wind happens at night after the sun has set and the land starts to cool.

• The land cools down faster than the sea, so the air over the sea is now warmer.

• Cooler air from the land then moves out towards the sea to fill the space.

Multiple Choice

At night, when the land is cooler than the ocean, what type of local wind occurs?

• A mountain breeze

• A sea breeze

• A land breeze

• A valley breeze

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Global Winds and the Coriolis Effect

• Global winds are large wind systems that travel long distances across Earth.

• ​The Earth's rotation causes these winds to follow a curved path.

• This curving phenomenon is known as the Coriolis effect.

• Because of the Coriolis effect, winds curve to the east in the Northern Hemisphere and to the west in the Southern Hemisphere.

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Multiple Choice

What is the name for the apparent curving of winds due to the Earth's rotation?

• The temperature effect

• The global wind effect

• The pressure effect

• The Coriolis effect

Major Global Wind Belts

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Trade Winds

• ​These winds blow from 30° latitude almost to the equator.

• ​​Due to the Coriolis effect, they curve toward the west.

• ​They are known for their consistent speed and direction.

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Westerlies

• ​These winds are found between 30° and 60° latitude.

• ​​They blow toward the poles from the west to the east.

• ​They can carry moist air, which produces rain and snow.

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Polar Easterlies

• ​These winds extend from the poles to about 60° latitude.

• ​​They form from cold, sinking air that moves from the poles.

• ​These cold winds blow from the east to the west.

Multiple Choice

A weather pattern is moving from west to east across the United States. Which global wind belt is responsible for this?

• Westerlies

• Polar Easterlies

• Trade Winds

• Sea Breezes

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Common Misconceptions About Wind

Misconception	Correction
Wind always blows in a straight line.	Wind follows a curved path due to the Earth's rotation (Coriolis effect).
Air pressure is the same everywhere.	Uneven heating from the sun creates high and low-pressure zones.
Land and water heat up at the same rate.	Land heats and cools much faster than water, creating coastal breezes.

Multiple Choice

Based on the daily heating and cooling cycle of land, why does a sea breeze occur during the day and a land breeze at night?

• The ocean currents change direction at night, pulling the air from the land.

• Land heats faster than water during the day, creating low pressure over land and high pressure over the sea.

• The moon's gravity is stronger over the land at night.

• Global wind patterns are stronger during the day.

Multiple Choice

During a sunny daytime at the beach, which local wind forms because land heats up faster than the sea, causing cool air from the water to move inland?

• Land breeze

• Sea breeze

• Valley breeze

• Mountain breeze

Multiple Choice

A ship is sailing from North America to Europe, which is an eastward journey. To take advantage of favorable winds, in which wind belt should the ship primarily travel?

• The Trade Winds, because they are consistent and strong.

• The Doldrums, because there is very little wind.

• The Polar Easterlies, because they originate from the east.

• The Westerlies, because they blow from west to east.

Multiple Choice

Which global wind pattern blows from about 30° latitude toward the equator and curves westward due to the Coriolis effect?

• Westerlies

• Polar easterlies

• Jet stream

• Trade winds

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Summary

• Wind is moving air created by pressure differences from Earth's uneven heating.

• Air flows from high to low pressure; a bigger difference means stronger wind.

• Local winds are created by landforms, while global winds are curved by Earth's rotation.

• The three main global wind belts are the Trade Winds, Westerlies, and Easterlies.

Poll

On a scale of 1-4, how confident are you about explaining the difference between local and global winds?

• 1

• 2

• 3

• 4