1. Weather

2. Weather Lesson 1: Atmospheric Pressure
Earth’s atmosphere has layers.
As you go up though the atmosphere, temperature and air pressure change.
Air pressure = atmospheric pressure.
Higher you go up, less pressure (air particles are farther apart)
Closest to the Earth’s surface, air pressure is the greatest (weight of air above it, pushing down on air below. Particles squeezed together)

3. More About Atmospheric Pressure
Air is invisible but has weight and mass!
Air is pulled to Earth by what force? g________
Particles of air move in all directions.
Why doesn’t a closed paper bag collapse under this pressure?
Air i__________ also pushes o____.
Airplane pilots use altimeters to determine how high they’re flying. These measure air pressure, not altitude!

4. Convection Currents
When cool air and warm air are next to each other, which will sink and which will rise? Why?
Earth’s surfaces do not heat evenly. Which would heat to cool more quickly, land or water?
These temperature differences
near water cause winds called
convection currents to occur.

5. Wind Temperature differences cause wind
(sinking cool air and rising warm air).
Moving air causes all weather.
Convection heating happens in the air and in ocean water, and affects the rock deep inside the Earth.
What is the source of energy that causes winds to form?

6. Uneven Heating Due to Earth’s Tilt
Earth is not heated evenly. Temperatures near the ________ get much more direct energy from the sun than temperatures at the _________.
This uneven heating is due to Earth’s tilt.
The uneven heating leads to convection currents, both locally and around the world, which cause wind.