Simulations

This chapter has continued the process begun in Chapter 1 of equipping you with a basic inventory of tools for investigating the atmosphere. The two major tools introduced in this chapter are more abstract than the weather instruments of Chapter 1. They are the the atomic model of matter and the kinetic theory of gasses. The first states that protons, neutrons, and electrons combine to make atoms, which themselves combine to make molecules of various compounds. The atmosphere, you saw, is molecules of various atoms, molecules, and larger clumps of molecules called aerosols and particles.

A basic result of kinetic theory is that the temperature of a gas is a measure of the speed at which its molecules are moving. Kinetic theory provides a connection between events at the molecular level and larger-scale properties we can measure, such as temperature and pressure.

Thus equipped, you began in earnest to explore the chapter question: Is the atmosphere composition changing? The short answer clearly is yes: it always has and always will. The long answer is very long indeed: the atmosphere contains a great number of different substances that can have significant impacts on life and/or the environment. The relative proportions of oxygen and nitrogen, which comprise well over 90% of the atmosphere, are changing little from year to year. However, concentrations of many problem substances, such as ozone, carbon dioxide, and sulfur dioxide, are subject to change, in many cases due to human influences.

You took a tour of the atmosphere's structure in the vertical and studied the depletion of the stratosphere ozone layer. The chapter concluded with a consideration of the very large composition changes our atmosphere has undergone in the geologic past and the highly divergent paths along which the atmospheres of our neighboring planets, Venus and Mars, have evolved.

Simulation 1 (1285.0K)

Simulation 2 (594.0K)