BACKGROUND:
The atmosphere is the envelope of
gases that surrounds the Earth. This envelope is part of the “spheres,”
including lithosphere (rock) and hydrosphere (water). The major
elements in the atmosphere include heat (from the Sun) and moisture.
Varying amounts of solar radiation (heat) and moisture cause different
types of air pressure to form, which assist wind to form. The moving
of the Earth itself, also “pushes” wind to move in certain directions.
The Sun's rays heats up the water and land, creates moisture and pressure
over a region. These differences in air pressure cause the wind to
move and when all these elements meet in different forms, they cause different
types of weather.
Air is composed of many gases like oxygen,
carbon dioxide, nitrogen, and argon. Gases like oxygen and nitrogen
are elements, but some gases like carbon dioxide are compounds.
At about 100 kilometers (60 miles) the
atmosphere is very thin, which is almost impossible to breathe without
artificial air. Beyond the atmosphere there is no air at all.
The bulk of the air is found in the lower portions of the atmosphere.
PROCEDURE:
- Ask the students if people
can live with no atmosphere (about 120 km). No, people need
air to live. More specifically, we need the oxygen that is present
in air.
- Introduce the word "atmosphere" to
students. Emphasize with the students that the Sun is not in our
atmosphere, but it heats up the air, which causes movement of the atmosphere.
Use the worksheet to review some of the different forms of air and moisture
we experience in the atmosphere. Remember, there would be no rain
or snow without an atmosphere. All of our weather is only within
the lower part of the atmosphere. Cumulus clouds are the fluffy
white ones, nimbus refer to clouds that are gray and usually mean rain.
- The recommended book Air is All Around You is an
introduction to the study of the atmosphere. Throughout the book
there are many experiments that can be done during class or as homework
assignments.
