Some interesting ideas and facts about air as expressed in Michigan Essential Goals and Objectives for Science Education K-12 (MEGOSE, 1991)  This is by no means intended to serve as an exhaustive list of such ideas.

• Air can offer resistance to motion.  (MEGOSE, 1991, p. 96)

• Air (or at least some of the gases that make up air) is needed by all organisms to stay alive.  (MEGOSE, 1991, p. 73)

•  “A scientific understanding of weather rests on an image of the atmosphere as a dynamic blanket of air completely covering an extremely large, spherical earth.  This dynamic expanse of air has regions of various temperatures and humidities that are constantly moving and interacting.”  (MEGOSE, 1991, p. 122)

•  “[K]nowledge of general patterns of air movement in the atmosphere -- specifically air masses, fronts, prevailing winds and the jet stream – [can be used] to explain and predict changing weather conditions.  [Such] … explanations … include the ideas that warm and cold air masses -- heated in warm regions or cooled in polar regions -- move across large areas of land, affecting local temperatures.  When they collide, the convection currents that result drive the development of storms.”  (MEGOSE, 1991, p. 124)

• “[A]ir is a substance, and … water can exist as an invisible gas mixed in the air.”  (MEGOSE, 1991, p. 122)

• Air is made up of extremely small particles called molecules.  (MEGOSE, 1991, p. 122)

• “[T]he atmosphere is a mixture of molecules of air (oxygen, nitrogen, etc.) and [invisible] molecules of water.”  (MEGOSE, 1991, p. 124)

• Air usually includes some water vapor, which is water in its gaseous form or state.  “The amount of water vapor in the air has many important consequences for regional climates and personal human comfort.”  (MEGOSE, 1991, p. 116)

• Rapid heating, and the resulting expansion, of air caused by lightning, yields a “shock wave” in the air, which we then experience as thunder.  (MEGOSE, 1991, p. 124)