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Lesson Title: Sea Level Rise: Measuring Thermal ExpansionGrade Level: 11-12Subject Area(s): Marine ScienceAssociated with: Chemistry Unit Time Required: 1 class period (beginning and end of experiment) BackgroundCore samples, tide gauge readings, and, most recently, satellite measurements tell us that over the past century, the Global Mean Sea Level (GMSL) has risen by 4 to 8 inches (10 to 20 centimeters). However, the annual rate of rise over the past 20 years has been 0.13 inches (3.2 millimeters) a year, roughly twice the average speed of the preceding 80 years. Over the past century, the burning of fossil fuels and other human and natural activities has released enormous amounts of heat-trapping gases into the atmosphere. These emissions have caused the Earth's surface temperature to rise, and the oceans absorb about 80 percent of this additional heat. The rise in sea levels is linked to three primary factors, all induced by this ongoing global climate change, one of which is: Thermal expansion: When water heats up, it expands. About half of the past century's rise in sea level is attributable to warmer oceans simply occupying more space. (National Geographic)It is estimated that most of the increase in sea level will occur as the result of global warming, which will cause thermal expansion of the oceans. Thermal expansion is the seawater expanding because of the higher temperature of the water. Since the oceans absorb heat from the atmosphere, when the atmosphere becomes warmer so will the oceans. Warm seawater has a greater volume than cold seawater. As the temperature of the ocean increases so will the total ocean volume. The increased volume will cause the level of the water in the oceans to rise. (COSEE) Learning Objectives:Students will be able to link thermal expansion of water in the flask to sea-level rise of our oceans.Students will be able to understand how increased water temperatures change the volume of water.Students will understand why thermal expansion is a concern for the Tampa Bay Area.Students will be able to link human activity to sea level rise.Materials:500mL (recommended) or 250 mL volumetric flaskTwo-hole rubber stopper (Very important!!! Second hole is to allow expanding air to escape.)Hot PlateThermometerMarkerMetric rulerDropper or Pipette500ml and 10ml graduated cylindersMarking penStudent Record SheetSet-up of equipment and close-up of flask with marks made by students showing rise in water level for every 10°C change in temperature.Procedure:Discuss Climate Change and Sea-Level Rise in class. Students will be performing an experiment on how thermal expansion of water contributes to sea level rise. Add water to the flask so that there is some water in its neck (ignore the fill line stamped/etched onto the flask). Place the thermometer in the flask and be sure to take an accurate first reading.Mark the level on the glass with a marker. Make and Record your initial predictions: What do you think will happen to the water in the flask as you begin to heat it?Place the flask on the hot plate, and gradually heat the water to no more than 95o CMake a mark on the neck of the flask each time the temperature increases by 10 o C.Allow the flask to cool and pour out the waterUse the ruler to measure the height of the water for each mark that you made on the flask.Refill the flask with cool water to the highest markUsing a dropper (or pipette) and the 10mL graduated cylinder, measure the volume of water between each mark and record your measurements (remember the top mark is the water’s volume at the highest temperature). Use the 500mL graduated cylinder to measure the initial volume of water and record your measurement.Enter your data in the data chart.Make two graphs – one of temperature vs. height, and one of temperature vs. volume. Plot each of your data points on the graph, then use a ruler or straight edge, draw the line of best fit. A line of best fit is the line that comes the closest to connecting the points you plotted (the point should all be near the line).Lesson Title: Sea Level Rise: Measuring Thermal ExpansionInitial Predictions: What are all the things that you think will happen to the water in the flask as you heat it?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Data table: Change in Temperature (o C)Volume of water in flask (mL)Change in volume-Total-(mL)05420.0205453.030546.54.550549.87.860550.98.980553.611.6Follow-up questions:1) What happened to the water level in the flask as temperature increased?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________2) How would you describe the relationship between the rise in temperature and the rise in the water level?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________3) Why does the water level in the flask change over time? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________4) How do you think this is related to global warming’s contribution to sea level rise in our oceans?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Relate your data collected to actual Sea Level Rise of the Atlantic OceanUsing data from the NOAA fact table below, calculate the rise in sea level using the data you collected and the following procedureFigure 1 – NOAA Fact TableOceanArea (km2)Volume (km3)Maximum Depth (m)Average Depth (m)Volume most affected by GCC(km3)Arctic15,558,00018,750,0005567120515,558,000Atlantic85,133,000310,410,9008486364685,133,000Indian70,560,000264,000,0007906374170,560,000Pacific161,760,000660,000,000108034080161,760,000Procedure to calculate sea level rise1. First, calculate the slope of the graph to find the increase in volume per degree Celsius in their flask (don’t forget to include units). Slope = m = ?V?T (rise over run) m = (8.0mL-0.0)mL(55℃-0.0)℃m = 8mL55℃ ≈ 0.15mL/°C2. Next, find the coefficient of expansion (β) by dividing the slope found in step 1 by the initial volume of water in the flask. (If you heat any volume of water by one degree, you can multiply it by this coefficient to find its new volume)Coefficient of expansion = β = mVβ = 0.15mL/°C542mL ≈ 0.00028/°C3. Use the coefficient of expansion (β) found in step 2 and the data in Figure 1 to find how much the change in volume (?V) of the top 1,000m (1.0km) of one of the oceans would increase per degree, due to thermal expansion?V = βV(where V is the volume most affected by climate change for an ocean)?V for the Atlantic Ocean = 85,133,000 km3 × 0.00028/℃?Atlantic = 24,000 km3/℃4. Finally, calculate the sea level rise (?h) per degree Celsius for the ocean you chose in the previous step. Divide the change in volume per degree (?V) by the Area of the ocean listed in Figure 1.?h = ΔVA (Where A is the area of the ocean)?Atlantic = 24,000 km385,133,000 km2 ≈ 0.00028 km/℃ = 0.28 m/℃Conclusions and Data Analysis:1) Based on what you know about the Tampa Bay area, how could thermal expansion impact the lives of the citizens of Tampa Bay?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________2) Explore this website to see if your predictions were correct: (Interactive map does not work in Internet Explorer)How will the predicted changes in sea level affect the Tampa Bay area?One foot? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Three feet? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Five feet? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________Ten feet? _______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________3) How can we decrease the threat of sea-level rise of our oceans? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________4) What personal actions can you take to help slow the rise of sea level? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________5) Test your knowledge of Thermal Expansion and Sea-Level Rise: in Volume of water (mL)00Rise in Volume of water (mL) Temperature (o C) ................
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