### Summary

Students will analyze data of tornadoes throughout the United States. They will create a bar graph of the number of tornadoes for the top ten states in the country and then calculate the median and the mode of the data.

### Engineering Connection

### Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the *Achievement Standard Network (ASN)*, a project of *JES & Co. *(www.jesandco.org).

In the ASN, standards are hierarchically structured: first by source; *e.g.*, by state; within source by type; *e.g.*, science or mathematics; within type by subtype, then by grade, *etc*.

Click on the standard groupings to explore this hierarchy as it applies to this document.

### Learning Objectives

- Explain why engineers need to know where tornadoes occur and how engineers might analyze data to determine those patterns.
- Be able to rank states according to the number of tornadoes (greatest to least).
- Explain the difference between and how to calculate the median and the mode.
- Create bar graphs and interpret data of tornado occurrences.

### Materials List

- Ruler
- Graph paper
- Pencils
- Markers, crayons, or colored pencils
- Calculator
- Copy of either the Ranked Worksheet (easier) or the Alphabetized Worksheet (advanced)

### Introduction/Motivation

### Procedure

Before the Activity

- Decide if the students will work with the Ranked Worksheet or the Alphabetized Worksheet tables. (Note: the ranked data will be easier, whereas the alphabetized data will provide an extra challenge.)
- Copy the tables for each student.

With the Students

- Explain to the students that tornadoes can form in any state and that they will be looking to see which states have the most and least tornadoes.
- Ask students to predict which states they think will have the most and least tornadoes. What about their home state? Alaska? Hawaii? Students should write their prediction in their science journals or on a sheet of paper.
- Have the students get into pairs. Pass out either the Ranked Worksheet or the Alphabetized Worksheet to students.
- Have students create a bar graph of the ten states with the most tornadoes.
- Have students create a bar graph of the ten states with the least tornadoes.
- Which state actually has the most? (Answer: Texas) Which state has the least? (Answer: Alaska) Where there any surprises? Have students write the answer on their worksheets.
- Explain to students that the median is the middle value of a series of numbers, and mode is the number that occurs the most often.
- Have students find the median and the mode of the data set and record their values on their worksheets. Providing students with a ranked data set will be very helpful for this part. (The median will be between the 25th and 26th, ranked states, Wyoming and South Carolina respectively. The exact answer would be 428.5, but anything between 423 and 434 could be acceptable.) The mode is 886.
- Have the students look at their original predictions (what states they think will have the most and least tornadoes). Was their prediction right? How close were their predicted states to the median and mode of the data?
- Using engineering terms, have students write a summary of the data they graphed. Tell them to write a paragraph summarizing what the graphs tell them. This should be 3-4 sentences describing any patterns they see, the median and mode of the data, and why understanding the data is important to engineers.

### Troubleshooting Tips

### Assessment

Pre-Activity Assessment

*Prediction:*Have students predict which states have the most and fewest tornadoes. Have them write their answers down in their science journals or on a sheet of paper.

Activity Embedded Assessment

*Worksheet/ Pairs Check:*Have students work individually or in pairs on their worksheet. Students who work in pairs should check each other's answers.

Post Activity Assessment

*Prediction Revisited:*Have students review which states have the most and fewest tornadoes. Have them look at their predictions in their science journals or on a sheet of paper. Were they right?

*Graphing:*Students should create a bar graph of the ten states with the most number of tornadoes. Students then create a bar graph of the ten states with the least number of tornadoes.

*Engineering Analysis:*Have students write an engineering analysis of the data they graphed. Tell them to write a paragraph summarizing what the graphs tell them. This should be 3-4 sentences describing any patterns they see, the median and mode of the data, and why understanding the data is important to engineers.

### Activity Extensions

### References

http://www.tornadoproject.com/

http://www.noaa.gov/tornadoes.html

http://www.asce.org/pressroom/publicpolicy/ka0100_windhazard.cfm

http://www.nssl.noaa.gov/

http://www.noaa.gov/tornadoes.html

http://www.chaseday.com/tornadoes.htm

http://www.spc.noaa.gov/archive/tornadoes/st-trank.html

### Contributors

Jessica Todd, Melissa Straten, Malinda Schaefer Zarske, Janet Yowell

### Copyright

© 2004 by Regents of the University of Colorado.

### Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

### Acknowledgements

Last modified: April 20, 2015