The Earth System

Abstract

Materials • Bottles, 4 two liter clear soda bottles • Chopsticks • Liquid crystal thermometer • Matches • Tape • Water Advanced Planning Preparation Time: ~10 minutes 1. Review the instructions 2. Gather the necessary supplies. Lesson Summary Students use a soda bottle to explore how changes in temperature, pressure, and amount of particles in the atmosphere affect the formation of clouds. Students will gain an understanding of Earth's feedback mechanisms that help to keep it at a stable temperature. Key Concepts and Terms: albedo effect Albedo is the fraction of solar energy that is reflected back to space. The more reflective a surface, the higher the albedo (the range is 0-1). The elements of the climate system that most contribute to Earth's albedo are clouds, surface ice and snow, and aerosol haze. Variations in the albedo of these elements can have a significant impact on global climate. For example, the albedo for fresh snow can be as high as .87 (87% of incoming solar energy is reflected). When the portion of ocean and land that is covered by ice and snow increases, the increased area of high albedo can be a positive feedback that increases cooling and expands the area covered with ice and/or snow, which can increase cooling and further expand the area covered with ice and/or snow. This is known as the ice albedo effect. A decrease in ice and snow-which would damp (reduce) the albedo effect-would increase the amount of solar energy received, resulting in warmer temperatures that would diminish the area covered by ice and snow. This in turn would further damp the albedo effect. This is a negative feedback. cloud condensation nuclei (CCN)* In the atmosphere, clouds can form at relative humidities of less than 100%. This is due to the presence of minute water-attracting particles. Water vapor will stick to, and condense on, these particles to form clouds. Major sources of naturally occurring CCN are: r volcanoes-dust and sulfate particles; r oceans-sea salt and particles; r phytoplankton-sulfate particles; and r wildfires-soot and dust. CCN can also result from man's activities. In particular, CCN occur as a byproduct of any combustion process. This includes motor vehicles emissions, industrial activity, and controlled fires (slash and burn agriculture). Earth system science Science of Earth as a system composed of interacting subsystems. This approach emphasizes the interactive nature of the components and crosses traditional discipline boundaries. The …