ESS1+(5-6)+-+2


 * Students demonstrate an understanding of processes and change over time within earth systems by …**

2a __diagramming, labeling and e__ __ xplaining the processes of the water cycle including evaporation, precipitation, and run-off, condensation, transpiration, and groundwater. __ 2b __explaining how condensation of water vapor forms clouds which affects climate and weather.__

2c __developing models to explain how humidity, temperature, and altitude affect air pressure and how this affects local weather.__

2d __identifying composition and layers of earth’s atmosphere__

=What do these GSEs mean? What subtopics do students need to address to understand these GSEs?=

2a. Hydrologic (Water) Cycle
> Oceans > Glaciers and polar ice > Groundwater > Lakes and Rivers > Atmosphere > Biosphere > Precipitation > Evaporation > Run off > Transpiration > -sometimes a change of state is involved > Infiltration > Discharge or well-up of groundwater > Melting > Condensation > Evaporation > Sublimation > -how long is the water in each reservoir > -can the amount in the reservoirs change over time > -that it exists > -pore spaces > -movement of water
 * Cycles (definition and explanation)
 * Reservoirs (where is the water and how much is there)
 * Fluxes (movement of water between reservoirs)
 * Change of state
 * Time Scale
 * Groundwater

2b. Water in the atmosphere reservoir
> When a tea kettle boils and we see a cloud, what is that make of? (most will say, steam) > Warm air holds more water than cold air > Saturation vapor pressure > Condensation and Evaporation in dynamic equilibrium (is this too advanced for middle school?) > evaporation is a net flow of molecules to gas > condensation is a net flow of molecules to liquid > Vapor pressure > Air rising, expanding, and cooling > Relationship between clouds and precipitation
 * Climate vs Weather
 * Water vapor in the air – invisible – How do we know it is there?
 * What is a cloud made of? (condensate, not water vapor) How do we know?
 * Temperature/Water Vapor relationship
 * Molecular view of condensation and evaporation
 * Humidity and Relative Humidity
 * Dew Point
 * Condensation and Cloud Formation
 * Supersaturated air, condensation nuclei
 * Clouds can be a factor in climate (e.g., droughts, polar zones vs tropical zones, radiative forcing, etc.)

2c. Air Pressure
> Air rising/sinking and relationship to pressure > Relationship between weather (storms) and air pressure Air pressure-altitude relationship Temperature-altitude relationship
 * Air pressure
 * Air Pressure and weather

2d. Atmosphere
> Primary gases (N2, O2, Ar, CO2, etc) > -troposphere, tropopause, stratosphere, stratopause, mesosphere, mesopause, thermosphere, exosphere =What ideas to students need to understand before they can address the topics described above?= =What misconceptions are students likely to have about these topics?= Ideas prevalent in certain age ranges: > [|Misconceptions about Weather:] [|NARST 2000] > [|Salient points from the literature about understanding the water cycle] > [|Yale Forum on Climate Change – Common Misconceptions] > [|Polar Science Assessment Probes] =What phenomena and representations help students understand these topics?= TBD =What activities or activity sequences can be used to address these GSEs?= TBD
 * Composition of Earth’s Atmosphere
 * Layers of the atmosphere
 * Phase Change
 * Pore spaces in rocks/sediments
 * That it is a cycle; it has no beginning or end
 * That it is a matter cycle (as opposed to a time cycle), and that matter is conserved
 * That “hidden” processes get left out or are poorly understood, i.e., ground water, how it is held and how it moves, how much of it there is, where it can be and can’t be, how it gets back to the surface, etc. Processes such as evaporation and condensation are somewhat understood, but are poorly applied to the water cycle. For instance, few students can imagine the scale of evaporation from the ocean, that it is enough to replenish the water cycle.
 * Do not regard freezing/boiling as taking place at a specific temperature
 * See heat and temperature as the same thing
 * When a wet object dries, the water just “disappears” or penetrates the solid object
 * Expanding on groundwater… size/scale of pore spaces, amount of groundwater, importance to the water cycle, rate of movement of water
 * At ages 11 – 15: clouds were thought to be created when the vapor becomes cold. (The rain falls when the water drops become big and heavy.) None of the sample population explained how the clouds became cold.
 * Above the age range 11 – 15, weight was attributed to vapor and to small drops of water
 * Middle School Students in general: **The concept of evaporation is better understood than the concept of condensation.** Research on 4th-8th grade students demonstrated that many students think that clouds are made up of water vapor and that, when water vapor condenses, it falls as rain. Students did not recognize the clouds as being made up of tiny drops of water. They explain water as evaporating and going up to the clouds, then condensing and falling as rain, but fail to recognize that clouds can exist as tiny droplets of water long before it rains. It is also more common for students to know that clouds are made up of tiny droplets of water than it is for them to know that they can be made of tiny droplets of water or tiny ice crystals.
 * One (depressing!) study found that students at the high school level had beliefs similar to younger students. For example, students believed that clouds are formed by boiling—vapors from a tea kettle or the Sun boiling the sea; clouds are mostly smoke; clouds are made of cotton or wool; or clouds are bags of water.
 * I’ve seen raw data that indicate college students have similar beliefs about clouds as well—e.g. once clouds fill with water, that’s when it rains; when it rains, clouds empty, so you cannot see them anymore
 * Possible caution: many poor diagrams of the water cycle often show water evaporating and rising to form a white cloud and then moving to a dark cloud that appears to open and spill out streams of water. While the picture is intended to show changes in the same cloud before it rains, to a student it looks like two different clouds made up of seemingly different material—one made up of evaporated water and the other made of condensed water.
 * Links to sites about childern’s misconceptions about water cycle, clouds, etc.


 * NECAP 2008 Gr 08 04
 * NECAP 2008 Gr 08 04 Analysis