How Do Tornadoes Form? Tornadoes 3–5
LESSON PLAN 1 Tornadoes 3–5 Tornado Science How Do Tornadoes Form? The word “tornado” comes from the Spanish word tronada, which means “thunderstorm.” Although a tornado is not a thunderstorm, it would not exist without strong thunderstorms. A tornado is a violently rotating column of air extending from a thunderstorm to the ground. The most violent tornadoes have rotating winds of 250 miles (402 kilometers) per hour or more. Key Terms and Concepts air pressure anvil cloud atmosphere condense cumulonimbus cloud cumulus cloud downdraft Enhanced Fujita Scale funnel cloud hail mesocyclone supercell thunderhead tornado updraft vertical wind shear vortex Purpose To introduce students to the science of tornadoes Objectives The students will— • Use A Tornado Is Born to define tornado vocabulary using words and images. • Read A Tornado Is Born to learn how tornadoes form. • Work as a class to create a storyboard showing the birth of a tornado. • Use information and vocabulary about tornadoes to write a picture book—fiction or nonfiction—that illustrates the formation of tornadoes. • Investigate family memories about experiences with tornadoes; compare the recollections with the facts of physical science to explain why the clues helped make an accurate tornado prediction. (Home Connection) • Use Hail Maker to research and analyze the relationships among supercells, tornadoes and hail. (Linking Across the Curriculum). • Research the Internet to learn about supercells and straight-line winds and create a presentation to share their information with others. (Linking Across the Curriculum) Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 1 Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? • Set up, present and discuss observations of weather demonstrations, using the activity sheets Wind Maker, Storm Cloud, Tornado in a Bottle and Wind Shear. • Describe how each demonstration helps to explain tornado formation. • Use The Enhanced Fujita Scale of Tornado Intensity to understand and develop comparative scales. (Linking Across the Curriculum). • Research to learn about the Great Cyclone of 1896 that hit St. Louis, Missouri; use the Enhanced Fujita Scale to try to rate the tornado. (Linking Across the Curriculum) • Analyze the science, or lack of science, in works of art and drama in which tornadoes play a role. Predict possible danger that might proceed from misinformation about tornadoes. (Linking Across the Curriculum) Activities “Tornado Talk” “Making Weather” Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 2 “Tornado Talk” SET UP 45 minutes CONDUCT two 45-minute classes Language Arts: Writing and Research; Science: Earth Science and Physical Science Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? Materials • A Tornado Is Born, 1 copy per student • A variety of books on weather, especially tornadoes • Access to the Internet • Hail Maker, 1 copy per student or group (Linking Across the Curriculum) • Chalkboard and chalk or chart paper and markers Visit the American Red Cross Web site at www.redcross.org/disaster/masters 1. Display the classroom library of materials on the weather. Include a computer or computers with access to the Internet. 2. Distribute A Tornado Is Born. Ask students to use sources from your “weather library” and the Internet to define the list of words on page 1 of the activity sheet. Write the class definitions for each of the words on the chalkboard or large poster paper. Definitions for A Tornado Is Born anvil cloud: the upper portion of a cumulonimbus cloud that flattens spreads out, sometimes for hundreds of miles atmosphere: the mass of air surrounding the earth condense: to cause a gas or vapor to change into a liquid cumulonimbus cloud: a cloud that towers above ordinary cumulus clouds with stronger or severe storms. The cloud often has a more sharply outlined, defined appearance with relatively rapid rising motions that are visible. cumulus cloud: a column of rising air that has condensed into a dense cloud with distinct outlines. The cumulus cloud is the first stage of a developing thunderstorm, although most cumulus clouds do not form thunderstorms. downdraft: rapidly descending column of cooling air that causes heavy rains and violent wind gusts front: the boundary between two air masses with differing characteristics, such as temperature or humidity funnel cloud: a rotating, cone-shape column of air extending downward from the base of a thunderstorm. When a funnel cloud reaches the ground, it is called a tornado. mesocyclone: a rotating shaft of rapidly rising air within a storm. Under certain conditions, a mesocyclone can generate a tornado. supercell: a violent thunderstorm that has a persistent, rotating updraft and is capable of spawning tornadoes thunderhead: the upper portion of a swelling cumulus cloud, or the entire cumulonimbus cloud updraft: a column of warm, moist air that is rising in a thundercloud or supercell vertical wind shear: the change in the wind’s direction and speed with height vortex: a whirling mass of air in the form of a column or spiral Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 3 3. When the words are defined, divide students into small groups. Turn their attention to the second and third pages of the activity sheet. Have them work together to fill in the blanks of the tornado formation description on their activity sheets. Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? Answers to A Tornado Is Born, Pages 2 and 3 High in the atmosphere, cool air pushes against warm air. The place where the two kinds of air meet is called a front. A front can stretch over 100 miles (161 kilometers). On warm days, the air near the ground is much warmer than it is at higher elevations. Warm air rises by bubbling up from the ground, just like the bubbles in a pot of boiling water. If the air has enough moisture in it, the moisture condenses and forms cumulus clouds. Sometimes, the rising air is trapped by a layer of cooler air above it. As the day continues, the warm air builds up. If this pocket of warm air rises quickly, it can break through the cap of cooler air like water shooting up from a fountain and a thunderhead or cumulonimbus (kyu-mya-lo-NIM-buhs) cloud, grows, topped by an anvil cloud. The thunderheads most likely to cause tornadoes are those that form along and ahead of fronts. Strong, fast winds tend to blow along and above fronts. If slower surface winds blow opposite to the direction of the higher winds, a vertical wind shear forms. Vertical wind shear can cause the rising air in a thunderhead to begin to rotate. A supercell is a thunderstorm with a constantly rotating updraft. Supercells are responsible for a high percentage of severe weather events, especially tornadoes. If the rising column of air in a thunderhead begins to rotate, it is called a mesocyclone (mez-uh-SY-klon). In a mesocyclone, the updrafts and down drafts are in near balance, allowing the storm to continue for several hours. As a mesocyclone rotates, it stretches toward warm air near the ground. The lower part of the mesocyclone narrows. The narrower it becomes, the faster it spins. When this vortex dips down from the mesocyclone, it draws in warm, moist air. The air cools as it is pulled up into the column. Tiny droplets of water form and a whirling cloud appears. This cloud is called a funnel cloud. Some funnel clouds hang straight down from the storm cloud. Others stretch sideways through the sky. A funnel cloud may dip down and then retract into the mesocyclone, or it may touch the ground. If it touches the ground, the funnel cloud is called a tornado. Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 4 4. Challenge students to draw and label a storyboard showing the birth of a tornado as described on the activity sheet. The following resources will help students with illustrations as they work on the storyboards. Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? Resources: Animations of Tornado Formation • Prentice Hall, Geoscience Animations http://esminfo.prenhall.com/science/geoanimations/animations/ Tornadoes.html • MSNBC: Birth of a Tornado http://www.msnbc.com/modules/tornado/default.asp • USA Today: How Tornadoes Form http://www.usatoday.com/weather/graphics/tornadoes/flash.htm • National Weather Service: Thunderstorms, Tornadoes, Lightning http://www.nws.noaa.gov/om/brochures/ttl.pdf • NOAA: Tornadoes... Nature’s Most Violent Storms http://www.nssl.noaa.gov/edu/safety/tornadoguide.html Wrap-Up Have groups share their completed activity sheets and drawings in short presentations. Working with the class, compile a storyboard about the formation of a tornado from the best elements of the presentations. Challenge each group to work together to create a storybook for young children, entitled A Tornado Is Born. Their books can be fiction or nonfiction, but they must include all the correct material on tornado formation. Home Connection Have each student take home his or her activity sheet to share with family members. Ask family members to relate any personal memories they have about tornadic storms. What clues to the tornado’s approach did they observe? Briefly, discuss what students learned at home. Challenge them to work together to tie clues to the reality of a tornado’s formation. For example, why might hail be a good clue to the possible approach of a tornado? TEACHING NOTE The Hail Maker demonstration takes about four hours to set up. Linking Across the Curriculum Science: Earth Science and Physical Science Both tornadoes and hail form when atmospheric conditions are unstable. An unstable atmosphere occurs when the updraft of warm, moist air is strong enough to push through the top layer of colder, drier air. Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 5 1. Distribute Hail Maker and the needed materials to student groups. 2. Have the groups complete the demonstration and work together to answer the questions on the activity sheet. Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? Materials • Freezer, for use by all the groups For each group: • Hail Maker • Scissors • Wax paper • Saucer • Eyedropper • Cold tap water • Black construction paper Answers to Hail Maker, page 2 Observation of Layers You can see the different layers within the frozen droplet. The layers farthest from the center are the clearest; the inner layer is white. What You Discovered The ice pellets resemble hail because of the layers of ice within each. They are different from hail because they are not round and the number of layers is not dependent on the winds and temperature changes within a cloud. Challenge: Temperature differences may have an effect, because the addition of warm water might partially melt the previous layer of the ice pellet before it is refrozen, blurring the layers. Using ice-cooled water might change the clarity of the layers. The actual demonstration may differ depending on the temperature of the water used. 3. Ask students to use their demonstration and the information from A Tornado Is Born to explain the relationship between hail and tornadoes. If hail falls during a storm, does that mean a tornado is inevitable? Explain. Answer As water droplets condense when the warm moist air hits the cold air, they freeze. They will begin to fall but, if the updraft is strong enough, they will be pushed up into the cold air at the top of the thunderstorm and refreeze. They will continue to add moisture from the updraft and the new moisture will freeze in the cold air. Eventually, they become heavy enough that they fall to the ground. Science: Earth Science Storm damage from straight-line winds is also associated with supercells. Challenge interested students to research on the Internet to learn more about this weather event. When the research is complete, ask them to create a short presentation that explains what happens to cause this kind of storm and how it relates to tornadoes. • Desk lamp • Paper towel • Magnifying lens Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 6 “Making Weather” SET UP 45 minutes CONDUCT two 45-minute classes Science: Earth Science and Inquiry TEACHING NOTE “Tornado Talk,” the first activity in Lesson Plan 1, describes the Tornadoes 3–5 basics of tornado formation. Students will better understand “Making Weather” if they complete “Tornado Talk” first. LESSON PLAN 1 How Do Tornadoes Form? TEACHING NOTE Depending on your time constraints and your students’ interest and abilities, “Making Weather” activities can be teacher or student demonstrations. All directions and questions for discussion are provided on the student activity sheets. To conserve time, consider dividing the class into groups and having each perform and present a different demonstration. Materials for all four demonstrations: Wind Shear Wind Maker • Wind Maker • Wind Shear • 3” (8 cm) paper circle cut into a spiral • Toilet tissue tube • 10” (25 cm) piece of thread • 2 hardbound books • Heat source (light bulb) Tornado in a Bottle Storm Cloud • Tornado in a Bottle • Storm Cloud • Two 2-liter soda bottles with caps • Clear, plastic sweater box or similar container, 8” x 8” x 12” (20 x 20 x 30 cm) • Hammer and a 2” (5 cm) nail • Water (room temperature) • Balloon • Heated milk, about 140° F (78° C) measured on a candy thermometer • Food coloring • Scissors • About 2 quarts (2 liters) of water • Clean baby food jar • Plastic wrap • Rubber band • Sharp object, such as the end of a paper clip 1. Introduce the activity by discussing with students the importance of demonstrations to the understanding of difficult concepts. Explain that the demonstrations will help them better understand the physics behind tornado development. Visit the American Red Cross Web site at www.redcross.org/disaster/masters 2. Divide the students into four teams and assign one weather demonstration to each team. Help the teams gather the materials they need and, if necessary, guide them through the demonstrations within their groups. Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 7 3. When all the teams have worked through the demonstrations, give them time to discuss and agree on answers to the questions at the end of the sheet. 4. Help each team set up and present its weather demonstration and analysis to the rest of the class. Guide a brief discussion of each team’s findings and analysis with the class as a whole. Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? Team 1—Wind Maker Answer When you hold the spiral by the thread over the heat source, the spiral begins to swirl. When you move it away from the heat source, the spiral stops swirling. What You Discovered When the air around the heat source is heated, the warmer air rises (updraft) and the cooler air drops down (downdraft) causing air movement. This movement of air causes wind. Team 2—Storm Cloud Answer The warmer milk immediately rises toward the top of the container. It spreads into an anvil-shaped cloud as it hits the cooler water of the container and the water’s surface. As the milk cools, it sinks in pouches and then in tiny streams back into the water. What You Discovered A cumulonimbus cloud develops vertically (updrafts of moist air) and is often capped by an anvil-shaped cloud. This is a thunderstorm cloud, frequently accompanied by heavy rains, lightning, thunder and, sometimes, hail, tornadoes or strong winds. Team 3—Wind Shear Answer When you move the books in opposite directions, the horizontal tube rolls between the books and then shears off vertically. What You Discovered Wind shear is the effect of winds moving in opposite directions. When the tube hits the ground, it represents a tornado. The power of the winds aloft and the slower winds closer to the ground can make the rising air in a thunderhead start spinning, forming a column of spinning air (mesocyclone) that can be the basis of a tornado. Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 8 TEACHING NOTE In the Tornado-in-a-Bottle demonstration, you may substitute a commercial Tornado Tube for the connector between the two bottles. If you do not use a Tornado Tube, make sure you maintain close supervision of the students when they use the hammer and nails. Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? Team 4—Tornado in a Bottle What You Discovered The swirling motion builds energy and, as the water drops through the opening of the bottle, it forms a vortex (a spinning funnel shape). The energy of a real tornado comes from winds and wind shear that produce “rotation,” which results in the tornado vortex. As this energy is forced into the smaller opening, it becomes more violent because the molecules move closer to the center. Wrap-Up 1. Now, ask students to use the demonstrations to explain the following: • Why do tornadoes often form when the surface air is warm and very moist and the upper level air is cold? Answer from Wind Maker and Storm Cloud When the sun heats the ground, the air near it grows warm, too. The warm air rises, but sometimes it is trapped by a layer of cooler air above it. As the day progresses, the sun continues to shine, and more heated air pushes its way skyward. Finally, it breaks through. The warm air blasts high into the sky, like water shooting up from a fountain, and a thunderhead grows. • Why do these circumstances—warm, surface air and cooler, drier air aloft—result in thunderheads? What if the warm air is dry? Would thunderclouds form? Why or why not? Answer from Storm Cloud Thunderstorms must have warm, moist air to form. • What happens to air masses caught between surface winds moving in one direction and upper level winds moving in the other? Answer from Wind Shear Strong winds often blow high above fronts. The power of these winds, along with slower winds closer to the ground, can make the rising air in a thunderhead start rolling along a horizontal axis. • A tornado forms from a vertical, rotating mass of air called a mesocyclone. At first, the rotating air is horizontal. What probably causes it to lift up and become vertical? Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 9 Tornadoes 3–5 LESSON PLAN 1 How Do Tornadoes Form? Materials The Enhanced Fujita Scale of Tornado Intensity (Linking Across the Curriculum) Answer from Wind Shear and Wind Maker The powerful updrafts of the storm tilt the air rolling along the horizontal axis until it whirls along a vertical axis or vortex. • The mesocyclone acts like a vacuum cleaner. It sucks up more and more warm, moist air. What happens to the cold air at the top of the column? Answer from Wind Maker and Tornado in a Bottle The mesocyclone draws ground-hugging air up into itself, where it expands and cools, condensing and, thus, building the cloud base downward into a wall cloud. • In some mesocyclones, a smaller column of faster-spinning air forms inside the bottom of the mesocyclone. This column is usually less than a half mile wide. As it spins, it reaches toward the ground, drawing in more warm, moist air. The air cools as it is pulled up into the column. Tiny droplets of water form and a whirling cloud appears. This cloud is called a funnel cloud. If this funnel cloud touches the ground, it is called a tornado. What feeds the tornado cloud energy? Answer from Tornado in a Bottle The energy of a real tornado comes from winds and wind shear that produce “rotation,” which results in the tornado vortex. As this energy is forced into a smaller area, it becomes more violent because the molecules move closer to the center. Linking Across the Curriculum Science: Earth Science; Mathematics: Comparison Tornado winds are often too difficult or even impossible to measure. The Enhanced Fujita Scale (also known as the EF Scale) is a measurement of observed damage caused by tornadoes. The scale includes estimated wind speeds based on damage. Use The Enhanced Fujita Scale of Tornado Intensity to help the students understand and develop comparative scales of their own. Challenge students to create scales to measure and report information. For example, a scale of difficulty could be measured by the grades students earn on tests. A “D0” would be a test that 99 percent of the students ace; on a “D5,” no student earns an “A.” Students could set up a scale to rate distances between homes, schools, towns or states. “Your home is just a T0 away, but mine’s a full T4.” Science: Earth Science; Mathematics: Comparisons On May 27, 1896, a tornado struck the city of St. Louis, Missouri. The news media called it “The Great Cyclone” and took extensive pictures of the damage it caused. The Enhanced Fujita Scale was a long way from creation at that point, so no EF Scale measurement has been assigned this horrific tornado. In small groups, have students examine the pictures and text of the Great Cyclone of 1896 in light of the EF Scale. Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 10 TEACHING NOTE Go to the Photo Library of the National Oceanic and Atmospheric Administration at http://www.photolib.noaa.gov/nws/monsters.html. Click Tornadoes for pictures and click http://www.photolib.noaa.gov/nws/tornado .html for text. Tornadoes 3–5 In their opinion, what rating would the groups assign this historic tornado and why? Have each group make a short presentation to the class to share their rating and the reasons for it. When everyone is finished, invite further discussion on any differences in class opinion and on the kind of information they would need to make a more definitive classification. LESSON PLAN 1 Language Arts: Reading How Do Tornadoes Form? Lead a discussion of the impossible situations the students have seen in fictional accounts of tornadoes—from The Wizard of Oz to Twister. What scientific facts are misinterpreted or misrepresented? Can misinformation be dangerous? Explain. Visit the American Red Cross Web site at www.redcross.org/disaster/masters Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross 11 A Tornado Is Born Page 1 of 3 Name ________________________________________________________________________ Step 1: Use books, the Internet and other resources to define each of the words below. If possible, draw a picture of the word to help others understand its meaning. anvil cloud: atmosphere: condense: cumulus cloud: cumulonimbus cloud: downdraft: front: funnel cloud: mesocyclone: supercell: thunderhead: updraft: vortex: vertical wind shear: Visit the American Red Cross Web site at www.redcross.org/disaster/masters A TORNADO IS BORN Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross A Tornado Is Born Page 2 of 3 Step 2: Below is a description of the way tornadoes form. Some of the words are missing. Use the words from Step 1 to complete the description. Then, draw a storyboard on the back of the page showing the formation of a tornado. High in the _______________, cool air pushes against warm air. The place where the two kinds of air meet is called a ______. A front can stretch over 100 miles (161 kilometers). On warm days, the air near the ground is much warmer than it is at higher elevations. Warm air rises by bubbling up from the ground, just like the bubbles in a pot of boiling water. If the air has enough moisture in it, the moisture ____________ and forms ____________________. Sometimes, the rising air is trapped by a layer of cooler air above it. As the day continues, the warm air builds up. If this pocket of warm air rises quickly, it can break through the cap of cooler air like water shooting up from a fountain and a __________________, or _________________ (kyu-mya-lo-NIM-buhs) cloud grows, topped by an ____________. The thunderheads most likely to cause tornadoes are those that form along and ahead of fronts. Strong, fast winds tend to blow along and above fronts. If slower surface winds blow opposite to the direction of the higher winds, a _______________________ forms. Vertical wind shear can cause the rising air in a thunderhead to begin to rotate. A _____________ is a thunderstorm with a constantly rotating ____________. Supercells are responsible for a high percentage of severe weather events, especially _____________. Visit the American Red Cross Web site at www.redcross.org/disaster/masters A TORNADO IS BORN Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross A Tornado Is Born Page 3 of 3 If the rising column of air in a thunderhead begins to rotate, it is called a ______________ (mez-uh-SY-klon). In a mesocyclone the updrafts and _____________ are in near balance, allowing the storm to continue for several hours. As a mesocyclone rotates, it stretches toward warm air near the ground. The lower part of the mesocyclone narrows. The narrower it becomes, the faster it spins. When this _________ dips down from the mesocyclone, it draws in warm, moist air. The air cools as it is pulled up into the column. Tiny droplets of water form and a whirling cloud appears. This cloud is called a _______________. Some funnel clouds hang straight down from the storm cloud. Others stretch sideways through the sky. A funnel cloud may dip down and retract into the mesocyclone, or it may touch the ground. If it touches the ground, the funnel cloud is called a _______________. Visit the American Red Cross Web site at www.redcross.org/disaster/masters A TORNADO IS BORN Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Hail Maker Page 1 of 2 Name ________________________________________________________________________ Directions: Gather the following materials and follow the steps below to illustrate how hail forms within thunderclouds. What You Need— • Scissors • Wax paper • Saucer • Eyedropper • Cold tap water • Black construction paper • Desk lamp • Paper towel • Magnifying lens • Freezer What You Do— 1. Cut a piece of wax paper to fit into the saucer. Place the paper into the saucer. 2. Use the eyedropper to place, separately, about 5 drops of water onto the wax paper. 3. Place the saucer in the freezer. 4. After 30 minutes, remove the saucer and place a drop of water on top of each frozen drop. Put the saucer back in the freezer. 5. Repeat Step 4 twice more. Wait an hour after you last add water. (Note: For a more dramatic effect, use different colors of water to form each layer.) 6. Place the black paper under the desk lamp. Remove one of the ice pellets and dry it with a paper towel. Place the pellet with its flat side facing up on the black paper. 7. Use the magnifying lens to observe the structure of the ice. View it from different angles. (As you make your observations, replace melted ice pellets with others.) Visit the American Red Cross Web site at www.redcross.org/disaster/masters HAIL MAKER Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Hail Maker Page 2 of 2 Describe the color and clarity of each of the different layers. What You Discovered— How do these ice pellets resemble hail? How are they different? Challenge: Does the temperature of the water used to form each layer have an effect? Test your hypothesis: Use both warmer and colder (ice-cooled) water as you form your ice pellets. Visit the American Red Cross Web site at www.redcross.org/disaster/masters HAIL MAKER Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Wind Maker Page 1 of 2 Name ________________________________________________________________________ Directions: Gather the following materials and follow the steps below to illustrate how wind occurs. What You Need— • 3-in. (8-cm) paper circle cut into a spiral • 10-in. (25-cm) piece of thread • Heat source (light bulb) What You Do— 1. Tie the thread to the center of one end of the paper spiral. 2. Hold the spiral by the thread and place it over the heat source. What happens? 3. Move the spiral away from the heat source. What happens? Visit the American Red Cross Web site at www.redcross.org/disaster/masters WIND MAKER Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Wind Maker Page 2 of 2 What You Discovered— • What happens when the air around the heat source is heated? • What effect does that have on the air above? • How does the activity explain the creation of winds? (Remember, when air is warmed, its molecules are excited and move farther apart.) Visit the American Red Cross Web site at www.redcross.org/disaster/masters WIND MAKER Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Storm Cloud Page 1 of 2 Name ________________________________________________________________________ Directions: Gather the following materials and follow the steps below to illustrate how thunderstorm clouds form. What You Need— • Clear, plastic sweater box or similar container (8 in. x 8 in. x 12 in.) • Water (room temperature) • Heated milk (about 78o C or 140o F measured on a candy thermometer) • Clean baby food jar • Plastic wrap • Rubber band • Sharp object, such as the end of a paper clip What You Do— 1. Fill the clear plastic box about 3/4 full of water 2. Fill the baby food jar to the top with heated milk and stretch a single layer of plastic wrap over it tightly 3. Carefully place the baby food jar into one end of the filled plastic container and allow it to sit for a minute until the water settles 4. Using a sharp object, puncture several holes in the top of the plastic wrap. Observe from the sides and top of the plastic container 5. Illustrate or describe what happens immediately 6. Illustrate or describe what happens next Visit the American Red Cross Web site at www.redcross.org/disaster/masters STORM CLOUD Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Storm Cloud Page 2 of 2 7. Illustrate or describe what happens when the milk begins to cool and sink. What You Discovered— How does this demonstration apply to thunderstorm cloud formation? Challenge: Use the terms anvil cloud, updraft, virga, and mammatus clouds in your description. Visit the American Red Cross Web site at www.redcross.org/disaster/masters STORM CLOUD Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Wind Shear Page 1 of 1 Name ________________________________________________________________________ Directions: Gather the following materials and follow the steps below to illustrate wind shear and its role in creating tornadoes. What You Need— • Toilet tissue tube • 2 hardbound books What You Do— 1. Place the toilet tissue tube, horizontally, between the two books 2. Move the books in different directions as the tube rolls between them 3. Describe or illustrate what happens What You Discovered— If the top book represents the upper winds and the bottom book represents the lower winds, how does the movement represent wind shear? If the tube in its initial position represents a horizontal wind tunnel, what does the tube represent when it hits the ground? How does this illustrate real tornado formation? Visit the American Red Cross Web site at www.redcross.org/disaster/masters WIND SHEAR Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Tornado in a Bottle Page 1 of 2 Name ________________________________________________________________________ Directions: Gather the following materials and follow the steps below to illustrate some of the concepts behind tornado formation. What You Need— • Two 2-liter soda bottles with caps • Hammer and a 2-in. or 3-in. nail • Scissors • Balloon • Food coloring • About 2 liters (2 quarts) of water What You Do— 1. Use the hammer and nail to punch a hole through each bottle cap. Widen the holes to about 1/4 inch. 2. Cut the top off the balloon, leaving just 1 inch or so of the tight bottom. 3. Fill one bottle 2/3 full with water. Put a few drops of food coloring the water and swirl it around so the color mixes in. 4. Leave the other bottle empty. 5. Screw the caps on each bottle. 6. Fit one end of the balloon over the neck of the bottle with water in it. 7. Flip the empty bottle over and place the caps of the bottles together. 8. Fit the other end of the balloon over the neck of the empty bottle. 9. Turn the bottles over and shake the full bottle in a circular motion. 10. Illustrate or describe what happens. Visit the American Red Cross Web site at www.redcross.org/disaster/masters in TORNADO IN A BOTTLE Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross Tornado in a Bottle Page 2 of 2 What You Discovered— What part(s) of a tornado does this demonstrate? How does it compare to real tornado formation? Visit the American Red Cross Web site at www.redcross.org/disaster/masters TORNADO IN A BOTTLE Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross The Enhanced Fujita Scale of Tornado Intensity Page 1 of 2 Name ________________________________________________________________________ The winds of a tornado are often too difficult or even impossible to measure. The Enhanced Fujita Scale is a measurement of observed damage caused by tornadoes. The scale includes estimated wind speeds of 3-second gusts based on damage. You can read more about it at the National Oceanic and Atmospheric Administration’s Storm Prediction Center Web site (http://www.spc.noaa.gov/efscale/efscale.html). Challenge: Study the Enhanced Fujita Scale on the next page. Then, create scales to measure and compare the relative size or strength of other things: school or local teams, rivers, parks, buildings, pets, the success or failure of ______________________. Make sure your descriptions will allow others to use the scale to measure and compare similar items. Visit the American Red Cross Web site at www.redcross.org/disaster/masters THE ENHANCED FUJITA SCALE OF TORNADO INTENSITY Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross The Enhanced Fujita Scale of Tornado Intensity Page 2 of 2 EF Scale Number Wind Speed (3-second gusts) Description of Damage EF0 Light damage 65 to 85 mph (105–137 km/h) Causes some damage to siding, shingles and gutters; breaks branches from trees and overturns trees with shallow roots EF1 Moderate damage EF2 Considerable damage EF3 Severe damage EF4 Devastating damage EF5 Incredible damage Visit the American Red Cross Web site at www.redcross.org/disaster/masters 86 to 110 mph (138–177 km/h) Causes considerable roof damage; can uproot trees, bend flagpoles and large signs; may overturn single-wide mobile homes, tear off exterior doors and break windows and other glass 111 to 135 mph (178–217 km/h) Destroys most single-wide mobile homes; tears roofs off well-constructed homes and shifts these homes from their foundations; uproots or breaks large trees in half; debarks softwood trees; tosses and overturns cars; collapses flag poles and large signs 136 to 165 mph (218–266 km/h) Tears the bark from hardwood trees; destroys all but small portions of houses; causes severe damage to office buildings or shopping malls; overturns trains and throws cars; blows away structures with weak foundations 166 to 200 mph (267–322 km/h) Completely destroys well-built residences, large sections of school buildings and large office buildings; throws about cars and other large objects; tosses small objects like missiles More than 200 mph (more than 322 km/h) Causes significant structural deformation of mid- and high-rise buildings; throws automobile-sized missiles through the air 100 yards (91 meters) or more. To date, no EF5 tornadoes have been recorded. THE ENHANCED FUJITA SCALE OF TORNADO INTENSITY Masters of Disaster® Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form? Copyright 2007 The American National Red Cross
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