Do Now:

1. Print this file and Image 1, but also remain connected or log-on again to complete the Investigation.
2. Print the Weekly Water News file. (Note: check the WES website during the week in the event that new water news stories have been added.)

To Do Investigation:

1. Read Chapter 2 in the Water in the Earth System (WES) text and respond to the Chapter Progress Questions in the WES Investigation Manual.
2. Go to the WES Investigation Manual to begin Investigation 2A.
3. Return here (Tuesday Investigation 2A File) when instructed to do so.

WELCOME BACK: Procedure continued from Investigation Manual, Investigation 2A.

We have now seen how water responds to additions and losses of heat (i.e., temperature and/or phase changes). In nature, water in lakes and other water bodies gains and loses heat to the overlying atmosphere depending on which is warmer and which is cooler. In this portion of the investigation, we compare the monthly variation in mean temperature of the surface water at a buoy site in Lake Michigan with that of the overlying air. The purpose of the comparison is to answer the question: Assuming average temperature conditions, during what part of the year does Lake Michigan heat the overlying air and during what part of the year does the overlying air heat Lake Michigan?

The source of data for our comparison is temperature sensors mounted on a buoy that is moored at the northern end of Lake Michigan at latitude 45.33 N and longitude 86.42 W. Air temperature is measured at 4 m (13 ft) above the lake surface and water temperature is measured at a water depth of 0.6 m (2 ft). This instrumented buoy (No. 45002) is part of a coastal and lake observational network maintained by the National Data Buoy Center.

Image 1 is a plot of the difference between the mean monthly air and lake-surface temperatures at buoy 45002 ["45002 AIR-SEA TEMPERATURE (DEGREES C) 9/1979-11/2001"] based on observations during the period September 1979 to November 2001. The temperature difference in Celsius degrees is plotted according to the scale appearing on the vertical axis with positive values indicating the air temperature is higher than the water temperature and negative values indicating the air temperature is lower than the water temperature. Months of the year appear across the bottom horizontal axis. The range in air-water temperature difference (highest to lowest) is plotted for each month with the mean value indicated by a dot in the middle of the shaded bar. The mean temperature difference for each month is displayed in the lower portion of the graph.

17. For easy reference, draw a heavy dark line directly on the horizontal dotted line on the graph representing a zero difference in air-water temperature. Next, draw a smooth curve connecting the dots representing values of the mean monthly air-water temperature difference. The curved line you drew shows that on average, at this location on Lake Michigan, air temperature is higher than lake surface temperature from [(August through March) (April through July)].

18. The greatest monthly mean temperature contrast between the lake surface and overlying air occurs in [(winter)(summer)]. At that time, the [(air) (water)] is warmer.

19. Heat is always transferred from a warmer object to a colder object. According to our analysis, during average conditions heat is transferred from air to lake water from [(August through March) (April through July)] and from lake water to air from [(August through March) (April through July)].

20. At the intersection of the curve you drew with each vertical mid-month line, draw an arrow shaft between the dot denoting the mean value and the "0" line. Place an arrowhead on the end touching the "0" line. The arrows you drew pointing upward represent heat flow from water to air whereas arrows pointing downward represent heat flow from air to water. The longest arrow you drew was for the month of __________ and represents the time of the year of greatest average monthly flow of heat energy between air and water. This flow is [(from air to water) (from water to air)].

To access the source of buoy data used in this investigation, go to the DataStreme WES website and under Oceanic (and Inland Seas) Information, click on "Buoy Data." Click on the rectangle over the western Great Lakes region and then click on the label "45002" identifying the blue square over northern Lake Michigan. This buoy has been removed from the lake for the winter so that current data are unavailable.

Self-Assessment Revisited: Respond to the statements below. Compare your responses now with those you made at the beginning of the investigation. Has learning taken place?

Professional Practice Transfer:

Driving Question: State an additional Driving Question appropriate to your classroom that you have conceived as the result of conducting this Investigation.

Implementation: Describe how you would use what you have learned in this investigation to implement inquiry-based learning experiences for your students.

Place the answers to Investigation 2A and the above questions on the Investigations Response Form which will be available Thursday and linked from the DataStreme WES website. Directions for delivery of your weekly investigation will appear at the end of the Thursday online portion of Investigation 2B.

Back to DataStreme WES website

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