Content Representation
Course: Introduction to the Earth
Lesson Name: Rainfall Contouring Lab
Description of Student: This is an entry-level Earth science course with no prerequisites. The
course satisfies a general education requirement for a science with a lab. Student ages have
ranged from 17 to over 60, with a wide variety of backgrounds and educational goals. All are
English speaking, very rarely has there been an ESL student. Class sizes range from about 18 to
30, with 22 being the average. Most students are highly motivated and curious, a few are less
engaged in all of the lessons but are required to participate with the goal of them wanted to
become more active learners.
Big Idea: Use Google Earth and provided data to learn about weather, climate, topography, and
how data can be contoured. There are two sets of Student Learning Outcomes (SLO) based on
this Big Idea.
Primary SLOs:
Interpolate accurate contour intervals using given data set.
Interpret results of contouring to understand relationships between rainfall values and elevation.
Compare historic with projected rainfall values to determine amount of change.
Compare historic rainfall values with current vegetation types to understand relationships.
Evaluate potential changes to vegetation given projected rainfall values.
Secondary SLOs:
Become familiar with the operation of basic GoogleEarth functions.
Import/download data from a remote site via the Internet.
Manipulate layers to show/hide data sets.
Understand the fundamentals of geospatial data and some introductory uses for it.
Importance for Understanding: Many students are either unfamiliar with geospatial resources,
or don’t recognize the many potential uses for geospatial data analyses. Topographic and/or
bathymetric maps are used in geology, oceanography, and meteorology, yet few students
understand the methods used to produce them. Further, they may come to trust computer
generated contour maps and fail to notice errors if they don’t understand some of the basic
concepts of contouring. Contoured data provide a visual representation that can reveal errors or
anomalies in the data, allowing for better analyses, interpretation, and correction. Contour
interpolation is a good exercise in estimating values, which can help reinforce basic math
concepts.
Anticipated Student Misconceptions:
Rainfall values don’t vary that much with changes in elevation.
Vegetation is a function of soil types rather than climate conditions.
Climate is stable and does not change.
Contouring involves a great deal of complicated mathematics.
Contours are limited to changes in elevation, not other data sets.
Anticipated Difficulties:
Students are unfamiliar with Google Earth.
Older students may be technophobic.
Students fail to see the significance or benefit of contouring and tune out.
Students have a wide range of computer literacy, some will speed through the activity while
others will struggle. Keeping everyone on the same pace could be challenging.
Teaching Procedures:
Introduce contouring and contour maps. Explain their uses and benefits. Provide examples of
topographic, bathymetric, and meteorological maps to show how the data are represented.
Teach lesson on interpolation to show how a contour line is generated.
Provide basic rules of contouring. 1) Value along contour line remains the same. 2) Contour
lines do not cross, split, or touch (though they may appear to from an overhead view). 3)
Contour lines don’t end in the middle of a map, and they may form closed areas. 4) Interpolated
lines are smoothed curves.
Introduce Google Earth, and demonstrate some basic features and functions.
Have students use laptops to open and begin exploring some of the features of GoogleEarth.
Provide select “destinations” for students to locate and describe as part of a classroom
discussion.
Provide SRI STORE web address and have students locate, and download California data set to
their laptop. Demonstrate how to turn on and off various layers in the data set.
Guide students in turning off all layers, and then expanding the Precipitation Data Projected
Values – 2099 link, expanding the Single Values link, and then selecting the
ca_2099_average_annual_precipitation box. Demonstrate how when selected each data point
on the map will open a pop-up window containing information that will be required for
contouring.
FID values will be assigned to each student to plot the rainfall data on a five by five grid. A grid
is provided on a handout for the students to plot data and then contour. (The grid handout sheet
and 18 sets of the FID top row values are attached below.) The selected areas are focused in the
Coast Range and Sierra Nevada to provide more contour intervals. Contours could be done in
the Central Valley, but their density would be much lower.
The grid areas are adjacent to one another. When student contour maps are completed, students
then assemble a larger map aligning their grid to adjacent grids and noting how well their
contour lines match, or discussing why there are differences.
A discussion on the values, overall pattern of rainfall distribution, and its relationship to
elevation is then held. The intent is to get students to connect rainfall increases with increased
elevation on the west side of the Sierra, and the rain shadow effect on the east side of the Sierra.
Students are instructed to deselect the ca_2099_average_annual_precipitation box, and then
find and select the ca_average_annual_precipitation box to show historic rainfall averages.
Small group discussions are held to compare their contoured projected rainfall data with the
contoured historical average rainfall. Since data points are not provided in the historical average,
they must compare contoured areas to one another, rather than data points. The intent is to have
them discover that the projected rainfall values are significantly lower than the historical average
values.
The discussion is then expanded to include vegetation cover and the impact that changing rainfall
patterns may, or will, have on various species of plants and animals, including humans.
Assessment:
Students will be given a set of values that will have to be plotted on a grid, and then contoured.
Based on the contours, they will be asked a set of questions requiring them to describe the
landscape and any prominent landforms. Quiz example questions are attached below.
Students will be asked open-ended or multiple choice questions regarding contouring, contour
lines, the relationship between elevation and rainfall, rain shadow effect, vegetation responses to
changes in precipitation, and the potential effect on human water use as watershed production
changes. Example questions are attached below.
Introduction to the Earth
Precipitation Contours
Use the grid below to contour 25 data points from the GoogleEarth data set. Contour interval
will be determined by you given the range of values, using whole numbers. Label all contours.
Top row of grid, FID values
5 by 5 grid
1. 305 to 309
2. 310 to 314
3. 516 to 520
4. 818 to 822
5. 315 to 319
6. 148 to 152
7. 469 to 473
8. 276 to 280
9. 764 to 768
10. 1346 to 1350
11. 1438 to 1442
12. 1176 to 1180
13. 1561 to 1565
14. 1309 to 1313
15. 1708 to 1712
16. 1843 to 1847
17. 1917 to 1921
18. 1852 to 1856
Example Assessment Items
Multiple choice – correct answer underlined.
A bathymetric contour line is a line that:
A. Is at the same depth at all points along that line.
B. Shows how much the seabed rises or falls.
C. Can split to go around landforms on the seabed.
D. Will sometimes end within the boundaries of a map.
The difference between weather and climate is:
A. Climate describes short-term observations, weather is long-term.
B. Climate refers to Ice Ages, and weather is for warmer cycles.
C. Climate describes long-term observations, weather is short-term.
D. Climate and weather refer to the same observations over similar timeframes.
Winds are generated by:
A. The rapid rotation of the Earth.
B. Tidal influences of the Sun and Moon.
C. The differential heating of Earth’s different surfaces.
D. Mountain ranges.
E. Surface ocean currents.
The relative humidity of an air mass is defined as:
A. The total amount of water vapor in a parcel of air, measured in liters.
B. The temperature of a parcel of air over the open ocean.
C. The amount of water vapor in a parcel of air, relative to the total amount of water
vapor that the parcel of air could contain.
D. The amount of rainfall that a parcel of air can produce in a given amount of time.
In the Northern Hemisphere, a parcel of air moving away from a high pressure area will:
A. Move counterclockwise.
B. Move upward.
C. Move clockwise.
D. Be relatively stationary.
In the central portion of the Sierra Nevada mountain range, an increase in surface elevation from
west to east will cause rainfall totals to generally:
A. Remain the same.
B. Decrease.
C. Increase.
D. Produce a west slope rain shadow.
As water is evaporated, it becomes a component of a parcel of air that then:
A. Immediately causes precipitation.
B. Descends and draws cool air in behind it.
C. Rises, expands, and begins cooling.
D. Rises, compresses, and continues warming.
Open-ended – key elements provided
Describe contour lines and how they are used to describe a landscape.
Key elements of answer: Lines of equal elevation. Show a 3D landscape in 2D. Closer
lines show rapid changes in elevation, wide spacing shows less change. Can show stream
drainage patterns and north and south facing slopes, which are important for habitat
considerations.
Describe the influence that the Sierra Nevada mountains have on rainfall totals on both the west
and east sides of the range, and why that occurs. How does the vegetation indicate the difference
in rainfall?
Key elements of answer: As air and moisture are forced upward by the mountains from
west to east, it cools leading to greater amounts of precipitation at higher elevations. Descending
air on the east side of the Sierra is moisture depleted, and warms with compression leading to
reduced precipitation causing the rain shadow effect. The west slope vegetation is denser, larger,
and adapted to a wetter environment. The east slope vegetation is characterized by sparse,
smaller, desert type plants.
1
2
3
4
5
6
6,800
A
B
C
D
E
F
G
A. Using the letters and numbers to form a grid, plot the following depths at the proper
coordinates. The first one has been completed for you.
A,1 = 6,800
C,4 = 75
F,4 = 500
A,3 = 6,100
C,5 = 5,000
G,2 = 3,200
A,5 = 5,300
D,3 = 79
H,1 = 7,500
B,4 = 4,500
D,5 = 3,800
H,4 = 6,200
B,6 = 10,200
E,1 = 1,200
H,5 = 7,800
C,2 = 92
E, 2 = 48
H,6 = 10,400
C,3 = 45
E,6 = 8,100
B. Draw the contours for the depths 100, 500, 1,000, 5,000, and 10,000 meters and label each
contour with the proper depth.
H
C. Based on these contours, what is the prominent landform that is represented here?
Seamount