National Teachers Enhancement Network: Lesson Plan

Lesson Plan: Predicting Monthly Precipitation
Subject: Environmental Science/ Meteorology/ Weather Forecasting
Classtime: 100 minutes
Grade Level: 8-12

Materials/Technology:

students are expected to have basic computer and spreadsheet skills that include the ability to: download data from an Internet site, paste into the Excel spreadsheet program, parse this data, and appropriately replace any missing data.

These skills are taught in the lesson entitled: Dealing With Missing Data.

students will need an Internet accessible computer with Excel spreadsheet, the REAL (not "light") version; otherwise, results will not be consistent with lesson.

It is preferred, but not necessary, that computers have a mouse with both right and left click buttons.

Safety, Handling, Disposal:

Internet access should be monitored closely to prevent viewing of inappropriate sites.

Learner Outcomes: Students should be able to:

Log onto, and collect data from, a specific site on the Internet
Average and compare the data using the Excel spreadsheet program.
Make predictions from their data.
Determine the percent error of their predictions.

Problem/Purpose:

Sometimes the data we get from weather stations is incomplete and must be manipulated in order to fill in the missing pieces. After the missing pieces have been filled in, it is possible to compare the averages of precipitation data from specific months of previous years. Then it is possible to predict the amount of precipitation in the current year for these months. How much precipitation will there be in April (or any other month desired) this year based on averaged precipitation for the same month in previous years?

Background/ Inquiry:

The Internet site http://www.ncdc.noaa.gov/ol/climate/online/coop-precip.html offers precipitation data for each state in the United States. By combining sites like this with the Excel spreadsheet program, students can use real data to make scientifically sound predictions. The scientist is able to use a spreadsheet to average, graph, compare, and analyze data to determine relationships difficult to notice simply by studying large groups of numbers. In using a spreadsheet the students will learn to manipulate data in order to make calculations and valid predictions. In some data sets data is missing; this is indicated by the entry of '9999' on the spreadsheet. This data should be analyzed to fill in the missing piece(s) by interpolation.

The proper method for doing this is found in the lesson entitled: Dealing With Missing Data; the location is given above.

Vocabulary List: Here.

Hypothesis:

The amount of precipitation predicted for the month(s) of interest will be consistent with the precipitation for the same month(s) from previous years.

Procedure:

Get the data. Log onto the web, and access the following website: http://www.ncdc.noaa.gov/ol/climate/online/coop-precip.html. Now click on the tab labeled: Surface. Scroll down and click: U.S. Precipitation Data by State. Select the state you are interested in. Allow the data to collect until the location of interest is downloaded (There is a tremendous amount of data on these sites and the teacher should be advised that the browsers memory can be surpassed.) then click Stop on the toolbar at the top of the screen. Scroll through the data until you come to the specific location. Highlight all the data for this location by holding down the left mouse button and dragging the cursor down the screen. When all the data has been highlighted, click on the right mouse button and click on copy. If the mouse does not have right/left buttons, highlight the information in the same manner. On the menu bar at the top of the screen, select copy, or use the keystroke <command c>.
Paste the data into Excel spreadsheet, then parse the data.
Fill in the missing pieces of data using interpolation. Missing data is indicated by the number '9999'.
Average the data. After all missing data has been replaced properly, calculate the average amount of precipitation for the month(s) under study. To do this:
- Click on the cell at the bottom of the month to be averaged.
- Type = (an = should appear in the white bar underneath the menubar).
- On the far left side of the same line where the = appears, there should be a word in a box. To the right of the box there is a black triangle pointed down.
- Click and hold on the triangle.
- Select Average.
- A new box will appear with the word Average in the upper left. Under the word Average, the word Number 1 will be in bold, and the cells to be averaged will be highlighted to the right.
- You can change the cells to be averaged by clicking in the highlighted box and changing the formula to alter the cells' reference number.
- After modifications have been made, Click OK, or press Return.
- The average precipitation for that month for all years selected appears in the selected cell at the bottom of the column. Remember: precipitation data listed as 102 = 1.02 inches. For example, if your average is 65.782, the value indicated is equal to .65782 inches of precipitation.

Based on the history of the site(s), how much precipitation should be received for each month(s)?
Access the website again at the end of the month(s) for which precipitation predictions were made. Compare the predicted precipitation to the actual precipitation for the specific location.
Compute the percent error of the prediction(s) using the formula: {(actual value � predicted value)/ actual value}*100.

Results/Analysis:

Printed spreadsheet with the answers to the following:

Site Location ________________ Month________

Average Monthly Precipitation =_________

Actual Monthly Precipitation = _________

Monthly Precipitation % error = _____________

Conclusions:

The conclusion should include: the predicted precipitation for the month(s) in question; the actual value found after the monthly total has been posted; suspected reasons for differences in precipitation predicted and actual precipitation.

Example: Local news reported change in upper air flow compared to "normal" for the month(s) in question. El Nino.

Assessments:

Determine if students correctly located the URL. (Assess while student is actively "online".)
Determine if students accurately collected data. (Specific data is linked to specific locations.)
Printed spreadsheet of accurately parsed data will have all data in proper columns and correct labels and averages listed.
Determine if students accurately interpolated missing pieces of data. (Teacher follows steps outlined in lesson Dealing With Missing Data for specific data, then compares answer to student values used to replace missing data.)
Students accurately calculate the percent error of the predicted precipitation for the month(s) under investigation. (Teacher returns to site and downloads precipitation for the months under study, then calculates percent error using students values and % error formula above. Compare teacher values to students answer.)
The students write a brief summary of why the average or predicted precipitation value might differ from actual amounts of precipitation a specific location receives for the month(s) studied.
Teacher downloads data from a location not studied by students. Teacher parses and "cleans up" data; use directions in Dealing With Missing Data. Have students use Excel spreadsheet to calculate average of specific months determined by teacher.
Have students calculate percent error on data generated by teacher.
For a combined assessment for lessons: Dealing With Missing Data and Predicting Monthly Precipitation, send students to http://www.ncdc.noaa.gov/ol/climate/online/coop-precip.html and have them download, paste, parse, interpolate missing data, andcalculate average for a specific month and specific years for a teacher-specified location. This should be an "open book" or "open notes" practical assessment.
Have students list three reasons why it is advantageous to use a spreadsheet program.

Integration: Computer skills, mathematics (averages, comparisons, percentages, percent error).

Reflections:
Share your thoughts on this lesson with the NTEN team.

Please send an e-mail to Patti Harrison.

Extensions:

Have students collect precipitation for specific months from a site near their hometown and compare it to other locations in their state. This could be done over the course of a year and students would gain insight as to how their town relates to the other sites in the state.
Have students consult a topographic map and make predictions as to differences in precipitation they discovered in the data collected at other locations in their state.

References/Resources:

http://www.ncdc.noaa.gov/ol/climate/online/coop-precip.html
ESCI 517, Electronic Hydrology Course Materials

http://www.student.montana.edu/~uessc/esci517/syllabus.html

Credits
Contributing Teacher: Bryan E. Mastin, Houghton Academy
NTEN Course: ESCI 517 Electronic Hydrology
Instructor: Steve Custer
Developing Team:
T.L. Buck Buchanan, Patti Harrison, Don Samuelson, John Usher, Don Wilson
Original HTML Editors: Tyson N. Trebesch, Ryan Huddleston, Andy Tomascak, Ching-Kwong Chia

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