Part 2—Display Data in the Graphing Tool

Step 1 –
Display the Default Graph: Maximum Air Temperature

  1. On the GLOBE website, be sure that Reynolds Jr. Sr. High School is still selected (see Part 1). The default graph will be Maximum Air Temperature unless you select a different column for which the school has data.
  2. Begin by looking at Maximum Air Temperature measurements for Reynolds Jr. Sr. High School. Above the list of schools, in the green box, choose Make a Graph and click Go.
    Above the list of schools, in the green box, choose Make a Graph and click Go.

    Link on the GLOBE Web site that creates a graph or other data requests.
    3. When you click Make a Graph and Go, you launch the GLOBE Graphing Tool. The default graph always shows the Maximum Air Temperature data for the entire period of time that a school has been participating in the GLOBE program, but as you'll see later, there are many options for customizing your view of any data that the school has collected. In this case you are looking at the daily maximum temperature reading at Reynolds Jr. Sr. High School across an eleven-year time period. Focus on the years where the data collection was most frequent and consistent: 1996–2003.

    Graph: 1996 through 2003; maximum air temperature; Greenville, PA

  3. While looking at the graph above consider the following questions:
    • The Maximum Air Temperature graph is showing somewhat of a repeating pattern here. What do you think is the reason for this?
    • Is the pattern similar to one you might expect to see for maximum air temperature in your own city or town? If not, what are the differences?

    The graph shows 8 years of maximum air temperature. For each of those years the maximum air temperatures are lowest during the winter months (beginning and end of each year) and highest during the summer months (middle of each year). Greenville has a particular climate based on its geographic location and elevation, so the maximum temperatures across each year will look similar to one another.

    Responses will vary with location. Students in the Northern Hemisphere will have a similar peak of maximum air temperature during the middle of the year, but depending on location, the range of temperatures across a year could be quite different. (e.g., coastal cities would probably show less of a temperature range.) This question provides an opportunity to discuss the factors that influence one's local climate.

Step 2 –
Change the Time Frame of the Graph to Two Years

  1. Below the graph, there is a box labeled, "Graph Data and Display Section". In the left side of that box, change the upper Year date from 1995 to 1998. Change the Month date from 10 to 01. Leave the Day date at 01. This will change the starting date of the graph to January 1, 1998. In the lower date box, change the ending date of the graph to December 31, 1999.
  2. Below the section of the screen where you can change the time frame of the data displayed in the graph, change the size of the graph from small to large. At the bottom of the box, click the Redraw button.

    Below the graph, there is a box labeled, "Graph Data and Display Section"

    • In the left side of that box, change the upper Year date from 1995 to 1998. Change the Month date from 10 to 01. Leave the Day date at 01. This will change the starting date of the graph to January 1, 1998.
    • In the lower date box, change the ending date of the graph to December 31, 1999.
    • Below the section of the screen where you can change the time frame of the data displayed in the graph, change the size of the graph from small to large.
    • At the bottom of the box, click the Redraw button.

    GLOBE tool for selecting parameters to display in a graph
    3. You now have just two years of maximum temperatures on the screen—all of 1998 and 1999—and you may see that each day is represented by a small red triangle.
    Graph: 1998 and 1999; maximum air temperature; Greenville
  3. While viewing this new graph above, consider the following questions:
    • Look at the temperature scale, which runs along each edge of the graph. On approximately what date does the highest maximum daily temperature occur in 1998? When does it occur in 1999?
    • Compare the two years and describe the differences and similarities you see.

    The summer of 1998 is clearly cooler than the summer of 1999. In 1998 the highest maximum air temperature occurs in early October. In 1999 the highest maximum air temperature occurs in early August.

    Responses will vary. January of 1998 started with warmer weather than 1999, and the summer of 1998 was a cooler summer than the summer of 1999. The temperature range in 1999 was greater than the temperature range in 1998. Both years show the maximum air temperature generally increasing and decreasing in a similar way. In both years, there are days when the maximum air temperature jumps quite a bit above or drops below days before or after, and then returns to a more typical value.

Step 3 –
Add Data for Soil Moisture (10 cm) to the Graph

  1. In the Graph Data and Display Selection menu, be sure that Maximum Temperature is still highlighted. Then, holding down the Command (open apple) key (Mac) or Control key (PC), scroll down to Soil Moisture (10 cm) and highlight it. Click Redraw.

    In the list of databases below the graph, be sure that Maximum Temperature is still highlighted. Then, holding down the Command key (Mac) or Control key (PC), scroll down to Soil Moisture (10 cm) and highlight it. Click Redraw.


    GLOBE tool for selecting parameters to display in a graph
    2. You should now have two data sets that appear in the graph. Soil moisture content is defined in terms of weight. It is a measure of the weight of water that exists in a gram of soil. Notice that the scale along the right side of the graph has changed. The unit of measurement for soil moisture is gram/gram, or g/g.
  2. With your cursor over the graph itself, use control-click (Mac) or right-click (PC) to open a menu and save the image to the disk. Rename the image and save it in a new folder. Now re-open the image and print it.

    3. Graph: 1998 and 1999; maximum air temperature, soil moisture; Greenville
  3. While viewing this new graph above, consider the following questions:
    • During which months does soil moisture at 10 cm remain basically steady?
    • During which months does soil moisture at 10 cm change quite frequently?
    • What change do you notice as you compare soil moisture for 1998 with 1999?

    The soil moisture at 10 cm below the surface remains basically steady during the months of January, February, March, and April.

    Soil moisture levels change most between the end of April and the end of November. In 1999 soil moisture levels at 10 cm were lower for a longer period of time.

Step 4 –
Add Data for Soil Moisture (90 cm) to the Graph

  1. Holding down the Command key (Mac) or Control key (PC), and making sure that Maximum Temperature and Soil Moisture (10 cm) are still highlighted, highlight Soil Moisture (90 cm). Change the Data (Y) Axis Range to Use a fixed range, and click Redraw.
    1. Hold down the Command key (Mac) or Control key (PC) and highlight Soil Moisture (90 cm).
    2. Change the Data (Y) Axis Range to Use a fixed range.
    3. Click Redraw.
    4. As described in Step 3 above, download, rename, and save the image. Now re-open the image and print it.

      5. GLOBE tool for selecting parameters to display in a graph

    2. Graph: 1998 and 1999; maximum air temperature, soil moisture; Greenville
  2. While viewing this new graph above, consider the following questions:
    • In what ways is the graph of Soil Moisture (90 cm) similar to the graph of Soil Moisture (10 cm)?
    • In what ways are the two Soil Moisture graphs different?
    • How does the 1998 graph compare with the 1999 graph for soil moisture at each depth?

    Through April the soil moisture levels at 10 cm and 90 cm are both quite stable. Soil moisture at 90 cm remains stable later into the summer, after soil moisture at 10 cm has started to change dramatically. At 10 cm, the soil moisture in 1999 was more variable and for a longer period of time than it was in 1998. At 90 cm, soil moisture in 1999 dropped to a lower level than it did in 1998 and remained there for a longer period of time.

Step 5 –
Add Data for Rainfall to the Graph

  1. Hold down the Command key (Mac) or Control key (PC) and make sure that all three sets of data are still highlighted. From the top of the list, scroll down to Rainfall and highlight it. Make sure the option for the Data Axis Range is Use a fixed range, and click Redraw.
  2. Download, rename, and save the image. Then re-open the image and print it. You may want to use colored pencils to highlight the different data sets.
    Graph: 1998 and 1999; maximum air temperature, soil moisture, precipitation; Greenville
    3. Notice that a new scale has been added to the right of the graph, and that the unit of measurement is mm for millimeters of rain. There is now a lot of data crowded into a small space. In Part 3 you will be getting a closer look at the details. However, you should be able to see enough detail to answer this one last question about the data.
  3. While viewing the graph consider the following questions:
    • Look at the rainfall data for both years. Do you think that Greenville, PA has a rainy season?
    • Is there a rainy season where you live?
    There is no clear "rainy season" pattern in Greenville. Some months appear a little wetter than others, but rainy days are well distributed across the year.

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