"Surprise Glacier" © 2010 Jiuguang Wang
Do sea levels rise when ice melts? Does it matter whether the ice is on land or in the ocean? Students design an experiment to find out. They collect data, graph their results, and interpret their findings. Along the way, they learn about density, displacement, and climate change.
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Science & Engineering Practices
Developing and Using Models.
Develop and/or use models to describe and/or predict phenomena. (3-5; 6-8)
Asking Questions and Defining Problems. Ask questions that can be investigated and predict reasonable outcomes based on patterns such as cause and effect relationships. (3-5) Planning and Carrying out Investigations. Plan and conduct an investigation collaboratively to produce data to serve as the basis for evidence. (3-5) Collect data to produce data to serve as the basis for evidence to answer scientific questions. (6-8) Analyzing and Interpreting Data. Represent data in table and/or various graphical displays to reveal patterns that indicate relationships (3-5; 6-8). Analyze and interpret data to make sense of phenomena, using logical reasoning, mathematics, and/or computation (3-5). Constructing Explanations and Designing Solutions. Use evidence to construct or support an explanation or design a solution to a problem. (3-5) Construct an explanation using models or representations. (6-8) |
Disciplinary Core Ideas
ESS3.C: Human Impacts on Earth Systems.
Human activities in agriculture, industry, and everyday life have had major effects on land, vegetation, streams, oceans, air and even outer space. (Grade 5)
PS1.A: Structure and Properties of Matter. The amount (weight) of matter is conserved when it changes form, even in transitions in which it seems to vanish (Grade 5). The changes of state that occur with variations in temperature or pressure can be described and predicted using these models of matter. (6-8) ESS3.D: Global Climate Change. Human activities such as the release of greenhouse gases from burning fossil fuels, are major factors in the current rise in Earth's mean surface temperature (global warming) (6-8). |
Crosscutting Concepts
Cause and Effect.
Cause and effect relationships are routinely identified, tested, and used to explain change. (3-5; 6-8)
Stability and Change. Change is measured in terms of differences over time and may occur at different rates; Some systems appear stable, but over long periods of time will eventually change (3-5). Explanation of stability and change in natural or designed systems can be constructed by examining the changes over time and forces at different scales (6-8). |
In this lesson, students will
Students will:
Teacher tip: This activity can be performed as a demonstration or in student groups.
This activity was selected for inclusion in the NSF/NOAA/DOE-funded Climate Literacy and Energy Awareness Network's (CLEAN's) collection of educational resources!
CLEAN is a nationally recognized project in which climate scientists and educators rigorously review and select high-quality online resources to be part of a collection.
This lesson was also used by the National Parks Service to create a demonstration video.
This procedure is only a suggestion - it's okay if your students come up with something slightly different. Check to make sure they are investigating the correct question and control the variables they are not testing (i.e., each container should contain the same number of ice cubes, the same amount and arrangement of clay "land," and should start with approximately equal water levels).
Have another discussion about global climate change. Use the following questions to generate discussion:
One consequence of climate change is the melting of ice caps, glaciers, and sea ice, including polar ice in Greenland and Antarctica. Substantial melt of these massive glaciers will cause a rise in sea level along coastlines throughout the globe (Climate Institute, n.d.). This activity explores how melting ice impacts sea level.
Water is an unusual liquid because it expands when it freezes. In general, liquids do not expand upon freezing, but rather contract and become denser as temperature drops. Like other liquids, as water begins to cool, it becomes more and more dense. But, because of the physical structure of the water molecule, it continues to become denser until just before freezing, when it expands. This expansion occurs at the point at which freezing begins (around 4°C). At this temperature water molecules arrange themselves into a crystal lattice structure that is significantly less dense than the liquid form. Because of this decrease in density at the point of freezing, ice always floats on water (US Geological Survey, 2014).
When objects are totally submerged in water, they displace an amount of water equal to their volume. However, because ice floats on water and is not completely submerged, ice does not displace an amount of water equal to its volume. Instead, it displaces less than its total volume of water. The water that floating ice displaces is equal to the volume that the ice would take up if it melted and became water again. In other words, floating ice displaces water equal to the mass of the ice. When ice melts, the mass of the ice is conserved, but the crystal lattice structure of ice disappears and the volume decreases and becomes equal to the volume of water it displaced in its ice form.
Therefore, when floating ice melts, the melted water is equal only to the volume of the ice that was submerged. This means that when floating ice melts, it contributes no additional volume to the body of water. We see this phenomenon when we let ice melt in a glass of water. The water does not overflow because the ice has already displaced water equal to the volume it will take up upon melting.
Ice already in the oceans does not contribute to sea level rise, but ice covering land will contribute to sea level rise upon melting. See these Videos Explaining Climate Change featuring the same activity as in this lesson plan.
The effects of sea level rise are global. According to maps created by the Bay Conservation and Development Commission for the San Francisco Chronicle (Kay, 2007), a 1 meter rise in sea level would submerge "parts of Corte Madera, San Rafael, Hayward, Newark and much of the Silicon Valley shoreline." In San Francisco, "Mission Bay housing and office developments, Caltrain tracks, Candlestick Point redevelopment, Heron's Head Park...parts of Treasure Island, and the San Francisco and Oakland airports" would all be under water.
