Wind

Lesson 5.5

What causes Wind?

• Differences in air pressure are caused by unequal heating of the atmosphere– Discovery lab– What warms up faster? Soil or water?

Which is less dense?

• Cooler air is less dense and has higher pressure than warm air.

• Cooler air comes in contact with warm air, the cool air flows beneath the warm air.

Measuring Wind

• Described by Speed using anemometer. • Described by Direction

Windchill Factor

• The stronger the wind, the colder you feel.

Local Winds

• Caused by unequal heating of the Earth’s surface within a small area.

• Sea breeze – land warms up in daytime faster than water. Warm air less dense, rises, creating a low pressure, cool air blows in from over water and moves under the warm air.

• Land Breeze – At night, land cools off faster than the water, cool air from land moves under the warm air rising off the water.