Atmosphere IntroGreat Lakes Rocks

Teacher Education CourseSchool Year 2016-17

“It is sometimes said that scientists are unromantic, that their passion to figure out robs the world of beauty and mystery. But is it not stirring to understand how the world actually works — that white light is made of colors, that color is the way we perceive the wavelengths of light, that transparent air reflects light, that in so doing it discriminates among the waves, and that the sky is blue for the same reason that the sunset is red? It does no harm to the romance of the sunset to know a little bit about it.”

― Carl Sagan,

The atmosphere is matter that has mass (inertia)…

…and exerts

pressuredue to the pull ofgravity (weight).

gravity

The atmosphere is matter that has mass…

760 mm = 30 inchesof mercury

Units of Pressure Useful for Weather

1 atm 1013 millibars 760 mm of Hg 30 inches of Hg

14.7 lb/in2

With less air above…

as altitude increases, pressure decreases

Because air can move around…

air pressure pushes equally in all directions at a given location

Air is compressible

Highest PressureMost Dense

Lowest PressureLeast Dense

Concept Check: could we use suction cups to replace solar panels on the space station like we replace phone screens?

Global mean total precipitable water

Air makes up nearly all of the atmosphere but the small percentage of water vapor plays an important role in earth’s systems…

Compared to water vapor, there is an even smaller amount of solid particles in the atmosphere called aerosols…

Aerosols can affect cloud formation and precipitation (as well as affect air quality)

Summary – What is the atmosphere?The atmosphere is made of matter that has mass and exerts pressure due to gravity, which holds our atmosphere to the earth. That pressure due to gravity is equal in all directions (up, down, sideways) at a given height but generally decreases as height increases. The atmosphere’s density also generally decreases as height increases.

The matter that makes up the atmosphere is mostly air (gases like nitrogen, oxygen, argon) with a relatively small but important amount of water vapor (gas) and clouds (liquid and solid). The even smaller amount of solid particles called aerosols come from both natural and man made sources.

Inquiry Question for the DayHow does energy flow and matter

cycle in the atmosphere?

• T-H-C Organizer•What do you think?•How can we find out?•What do we conclude?