Science Curriculum Topic Study

Air & Atmosphere and Weather & Climate

I. Identify Adult Content Knowledge

Science for All Americans

· Planet enveloped by a thin blanket of air

· The earth has a variety of climatic patterns: temperature, precipitation, humidity, wind, & air pressure

· Energy comes from sun heating land, ocean, and air

· Transfer of heat energy at interfaces of atmosphere with land and oceans produces layers at different temperatures in both air and oceans. The layers rise or sink or mix and give rise to winds and ocean currents that carry heat energy between warm and cool regions

· Earth’s rotation curves the flow of winds and ocean currents

· Water cycle helps to determine climatic patterns: evaporation, rising, cooling, condensing, precipitation and collection of water in ground and surface water.

· Climatic changes occur due to factors such as advance or retreat of glaciers or huge volcanic eruptions or changes in atmospheric content or ocean temperature

Science Matters

• Three principal atmospheric cycles (weather, seasons, climate)
• Troposphere is warm layer of air next to surface of the earth – extends up to 40 feet. It contains most of the cloud systems we see from earth
• Stratosphere 9 to 150,000 feet)
• Mesosphere (to 260,000 feet)
• Ionosphere – plays a role in the overall behavior of the ocean of air
• Convection causes weather in near earth layers
• Lower atmosphere powered by solar energy – most solar energy is at equator where warm air expands and rises. The earth’s 24 hour rotation creates 3 large east-west convection cells – creating westerlies and easterlies depending on if it is northern or southern hemisphere respectively. Stagnant air masses (“doldrums”) are found at the equator
• Weather terms
• Temperature – rises and falls on a daily basis and seasonally and with altitude
• Barometric pressure is the weight of all the air overhead (14lbs/in²). Large air masses form vast circular currents, which pile up at margins (high pressure zones) and such air out of their centers (low pressure zones)
• Humidity – relative term – reported as a percentage. It is the amount of water vapor that the air can hold before it produces fog or rain. It depends on air temperature. Relative humidity is a measure of how much water the air actually holds, compared to how much water the air can absorb.
• Wind speed and direction – depends on topography, the location and temperature of large bodies or water, and distribution of high and low pressure air masses.
• Jet stream – high altitude wind currents that behave like fast moving rivers (about 8 miles high) Jet stream roughly divides cold northern air from warmer air in temperate regions. General trend in US is west to east.
• Airborne Pollen – pollutants in air reported during weather forecasts. It is described by arbitrary scale of particles per given volume of air.
• Greenhouse Effect – Effects of carbon dioxide in atmosphere. In a greenhouse, sunlight passes through glass and is absorbed by the materials on the inside. The heated materials give energy back as infrared radiation. The glass in essence traps the infrared radiation and warms the inside. Like glass, carbon dioxide transmits visible light energy from the sun. It also absorbs the infrared radiation that rises from the ground and holds heat in the atmosphere instead of reflecting it back into space. Global warming refers to this process of accumulated carbon dioxide (primarily from burning fossil fuels). Carbon dioxide has always been present in the atmosphere – more is just being added. Other gases like methane and water vapor can also add to the greenhouse effect. Carbon dioxide is the main source of the green house effect. Debate in science occurs on if global warming has already started and how much warming will eventually occur.

References:

§ Hazen, R.M. & Trefil, J. 1992. Science Matters: Achieving Scientific Literacy. New York: Anchor Books.

§ Keeley, P. 2005. Science Curriculum Topic Study: Bridging the Gap Between Standards and Practice. Thousand Oaks, CA: Corwin Press.

§ Rutherford, F. J. & Ahlgren, A. 1989. Science for All Americans: A Project 2061 Report. American Association for the Advancement of Science. New York: Oxford University Press, Inc. Note: This document is also available on the web at: http://www.project2061.org/publications/sfaa/online/sfaatoc.htm