WHAT IS A TORNADO?

The National Weather Service defines a tornado as "a violently rotating column of air pendant from a thunderstorm cloud and touching the ground." Each year, about 100,000 thunderstorms form over the United States. In an average year, between 600 and 1,000 of those thunderstorms generate tornadoes.

Although most U.S. tornadoes occur in only a handful of states, tornadoes can -- and do -- occur in every state. Every student in the country needs to be prepared to deal with the deadly storms. What do your students know about tornadoes? What do you know?

Do You Know That ...?

• Tornadoes are the most destructive of all weather-related events.
• On average, a tornado's path is 4 miles long and 400 yards wide but can be as long as 100 miles and as much as a mile wide.
• Tornadoes can reach heights of 60,000 feet.
• The average tornado travels at a speed of 25 to 40 mph., but tornadoes can reach speeds up to 70 mph.
• Winds inside a tornado can swirl at close to 300 mph.
• Tornadoes stay on the ground for an average of four to five minutes; however, a tornado can touch down several times.
• Most tornadoes move from southwest to northeast.
• Most tornadoes in the Northern Hemisphere rotate in a counter-clockwise direction. Most tornadoes in the Southern Hemisphere rotate in a clockwise direction.
• Building damage during a tornado happens when high winds cause a buildup of pressure on building surfaces. This pressure is related to wind velocity squared.
• Most tornadoes occur between 3 p.m. and 7 p.m.
• Tornadoes occur throughout the world; however, the greatest number of tornadoes and most intense tornadoes occur in the United States.
• About 800 tornadoes touch down in the United States each year.
• Half of all tornadoes occur during the spring months of April, May, and June.
• Tornadoes can form in any state but they occur most frequently in Alabama, Arkansas, Florida, Georgia, Illinois, Indiana, Iowa, Kansas, Louisiana, Mississippi, Missouri, Nebraska, Oklahoma, South Dakota, and Texas.
• Only 2 percent of tornadoes are considered violent, but those storms cause 70 percent of tornado-related deaths.
• On average, 100 people are killed by tornadoes each year.
• A National Oceanic and Atmospheric Administration (NOAA) weather alert radio receiver, equipped with a warning siren, can warn of an impending tornado when people are sleeping.

What more is there to know? The activities below will help your students explore weather, understand tornadoes and their power, and prepare them to act if a severe storm warning is issued for your area. Severe weather isn't any fun -- but these activities will be!

Note: Most of the activities are for students in grade 3 and above. Starred activities can be used with, or adapted for use with, students in the primary grades as well.

BE PREPARED!

Science -- learn about tornadoes. Encourage students to read How Do Tornadoes Form? and study the diagrams. Then have them click on the image of a tornado to view streaming video of a tornado at the National Center for Supercomputing Applications (NCSA). Ask students to use the diagrams to identify the formation of the tornado in the video.

Math -- solve word problems. Invite students to find the answers to the problems at Disaster Math.

Safety and art -- create a poster. Have students explore tornado safety at sites such as Are You Ready for a Tornado? (in English and Spanish), Tornado Safety, and How to Save Your Life. Have students work together to create a poster about tornado safety in school. Then ask each student to create a poster about tornado safety at home. Encourage students to take their posters home and discuss them with their families.

Reading -- analyze words. Explain to students that the word tornadocomes from the Spanish words tronado, meaning "thunderstorm," and tornar, meaning "to turn." Ask them to make a list of other English words that come from, or are formed from, words in other languages.

Technology -- go on a scavenger hunt. Invite students to complete the on-line Hunt for Tornadoes.

Language arts -- write a poem. Invite students to read the Cloud Poems written by first-grade students in Florida. Then ask them to write their own poems about tornadoes.

Lab science -- create a tornado. Help students follow Dorothy's Tornado Recipe to create a tornado in a bottle.

Math -- fun and games. Invite students to play Water, Wind and Earth. Ask younger students to keep track of the number of times they beat the computer and the number of times they're beaten by the computer and then help them make a table of the results. Ask older students to compute various probabilities related to the game. For example, they might find the probability that both "players" will make the same choice, of each combination of choices occurring, or of beating the computer in a five-game match if the computer is ahead two to one.

Art and science -- design a tornado-safe house. Encourage students to read Effects of High Winds. Then ask them to design a house that could withstand a tornado.

Geography -- make a map. Invite students to read about Doppler Radar and Tornadoes and have them use on-line resources to find the location of Doppler radar weather stations across the United States. Then have students indicate the locations of those weather stations on a map. Ask: Which weather station is most likely to observe tornadoes? What other kinds of weather is each Doppler weather station most likely to observe? What are the benefits of predicting severe storms as early as possible?

Community involvement -- talk to a meteorologist. As a follow up to the previous activity, invite a local meteorologist to visit the classroom to talk about Doppler radar and its use in predicting weather. Have students use what they have learned to prepare questions about Doppler, tornadoes, and local weather for the visitor.

WANT MORE?

Science -- take a quiz. Encourage students to explore Take the Quiz, prepared by the two eighth graders from Alaska.

Math -- make a double bar graph. Encourage students to track the number of tornadoes that occur during each of the next three months. Then have them make a double bar graph comparing that number to the average number of tornadoes that occur in the United States during each of those months.

Reading -- create a glossary. Encourage students to read about Tornadoes! Formation and then have them create an illustrated glossary of tornado-related terms.

Language arts -- research and write about tornadoes. Invite students to complete the Weather Activity for 3rd Grade.

Math -- figure it out. Have students study the information about Tornado Numbers, Deaths, Injuries, and Adjusted Damage 1950-1994. Then ask them to compare the state rankings for number of tornadoes and tornado deaths and discuss the results. For example, you might point out that Oklahoma had more than twice as many tornadoes as Mississippi, but Mississippi had more than 100 more deaths. Ask students to speculate on the reasons for that discrepancy as well as others they might find.

Language arts -- reading for comprehension. Invite students to read the Case Analysis of a Historic Killer Tornado Event in Kansas on 10 June 1938. Be sure they look at all the accompanying photographs. Offer a prize to the first student to identify the better-known version of this event. Then encourage students to read the fictional version for themselves -- or show the movie!

More Fun and Games. Invite students to choose from a variety of storm related Games, Quizzes and Challenges.

Science -- take a test. Invite students to visit Twister, the home page for the Warner Brothers movie, and take the storm chaser test to qualify for a research position at the Severe Weather Institute Research Lab.

TORNADO WARNING!

Be advised: The following sites provide excellent, completely developed units on tornadoes. Use them alone or as part of your own tornado study. Be sure, however, to supplement the units with some of the activities noted in this article!

• For middle-school students, Tornadoes, from Science With OAR, provides background information, activity sheets, links, and application and enrichment activities.
• For elementary students, Taming Tornadoes, from Link 2 Learn, includes discussion topics, links, and activities designed to provide non-threatening lessons about tornadoes. Though suggested for primary students, most students will need help to successfully complete the unit. It's appropriate -- with varying degrees of teacher assistance -- for all elementary students.

ADDITIONAL ON-LINE TORNADO RESOURCES

• Oklahoma Twisters The Oklahoman newspaper has put together an online section devoted to the 1999 tornadoes and their devastation. Read real-life accounts, view photos of the destruction, and listen to National Weather Service interviews.
• Or visit KFOR-TV, News Channel 4's coverage of the tornadoes.
• Tornado Project Online This is the definitive site for tornado information. If you can't find it anywhere else, you'll probably find it here.
• USA Today Tornado Information Index This site includes lots of easily read and understood information as well as many great graphics about tornado formation, history, prediction, safety, and more.
• Storm Spotter's Guide This National Oceanic and Atmospheric Association site provides lots of interesting and useful information about severe storms, including tornadoes.
• Tornadoes: Going Around in Circles The Why Files, funded by the National Science Foundation, contain a great deal of easy-to-read information about tornadoes.
• FEMA for Kids The Federal Emergency Management Agency provides lots of information for teachers and parents, as well as "Games, Quizzes, and Challenges" for kids.
• Severe Weather This clearly written and comprehensive site includes information about severe storms, including hurricanes and Tornadoes.
• Welcome to the Storm Chaser Homepage! The page includes information on storm chasers, links to weather information, and photographs of tornadoes.
• Turn! Turn! Turn! This article from Scientific American includes links to relevant images and forecasting instruments.
• Tornadoes The site provides a compilation of the most important tornado information from a number of more comprehensive sites.
• SPC Severe Storm Statistics The Storm Prediction Center (SPC) provides the latest statistical information about tornadoes that have occurred since 1996, as well as a current severe weather forecast.
• Power of Tornadoes This brief but kid-friendly tour of tornadoes includes a Quick Time movie of a tornado.
• Tornadoes This Nebraska site contains lots of valuable background information about tornadoes and related topics.
• Science With OAR A joint effort of the Office of Oceanic and Atmospheric Research (OAR) and the College of Education at the University of South, the site provides middle-school students and teachers with "research and investigation experiences using on-line resources." Lessons are on a variety of topics, including El Niño, storms, fisheries, the atmosphere, the Great Lakes, and oceans. This is a great site, with lots of information and activities.
• Tornadoes Explore Zone provides basic, easy-to-read information about tornadoes.
• WeatherNet Weather Maps The site offers an assortment of temperature, surface, and upper-air maps.
• Weatherwise The index to this on-line weather magazine includes a number of articles about tornadoes.
• Tornado Information for Kids The Champaign (Illinois) Public Library provides a list of tornado-related books, poems, and videos for students in kindergarten and up.
• WeatherOnline This is a good source for current weather information.
• National Weather Service -- Interactive Weather Information Network (IWIN) This is another good source for current weather information.
• Astronomy Picture of the Day Tornadoes on the Sun See a picture of tornadoes on the, and read a brief explanation of the phenomena.
• Both Hides Now This funny and irreverent song provides a vivid image of a tornado's power.

Article by Linda Starr
Education World®
Copyright © 1999 Education World