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Weather on the Move Teacher's Guide Editors: Brian A. Jerome Ph.D. Stephanie Zak Jerome Assistant Editors: Louise Marrier Hannah Fjeld Graphics: Fred Thodal Dean Ladago Lyndsey Canfield Heather Fjeld Visual Learning Company www.visuallearningco.com 1-800-453-8481 25 Union Street Brandon VT 05733 A Message from our Company . . . Visual Learning is a Vermont-based, family owned company specializing in the creation of science programs. As former classroom science teachers we have designed our programs to meet the needs and interests of both students and teachers. Our mission is to help educators and students meet educational goals while experiencing the thrill of science! Viewing Clearances The video and accompanying teacher’s guide are for instructional use only. In showing these programs, no admission charges are to be incurred. The programs are to be utilized in face-to-face classroom instructional settings, library settings, or similar instructional settings. Duplication Rights are available, but must be negotiated with the Visual Learning Company. Television, cable, or satellite rights are also available, but must be negotiated with the Visual Learning Company. Closed circuit rights are available, and are defined as the use of the program beyond a single classroom but within a single campus. Institutions wishing to utilize the program in multiple campuses must purchase the multiple campus version of the program, available at a slightly higher fee. Video streaming rights are available and must be negotiated with the Visual Learning Company. Discounts may be granted to institutions interested in purchasing programs in large quantities. These discounts may be negotiated with the Visual Learning Company. Use and Copyright: The purchase of this video program entitles the user the right to reproduce or duplicate, in whole or in part, this teacher’s guide and the black line master handouts for the purpose of teaching in conjunction with this video, Weather on the Move. The right is restricted only for use with this video program. Any reproduction or duplication, in whole or in part, of this guide and student masters for any purpose other than for use with this video program is prohibited. The video and this teacher’s guide are the exclusive property of the copyright holder. Copying, transmitting, or reproducing in any form, or by any means, without prior written permission from the copyright holder is prohibited (Title 17, U.S. Code Sections 501 and 506). Copyright © 2007 ISBN 978-1-59234-176-4 Page 2 Weather on the Move Visual Learning Company 1-800-453-8481 Table of Contents Visual Learning Company 1-800-453-8481 A Message from our Company 2 Viewing Clearances 2 Use and Copyright 2 National Standards Correlations 4 Student Learning Objectives 5 Assessment 6 Introducing the Program 7 Program Viewing Suggestions 7 Video Script 8 Answer Key to Student Assessments 12 Answer Key to Student Activities 13 Pre-Test 14 Post-Test 16 Video Review 18 Vocabulary 19 Writing Activity 20 Model of a Front 21 Name That Hurricane 23 Thunderstorm Safety Tips 25 Weather on the Move Page 3 National Standards Correlations Benchmarks for Science Literacy (Project 2061 - AAAS) Grades 3-5 The Physical Setting - The Earth (4B) By the end of the fifth grade, students should know that: • Air is a substance that surrounds us, takes up space, and whose movement we feel as wind. • When liquid water disappears, it turns into a gas (vapor) in the air and can reappear as a liquid when cooled, or as a solid if cooled below the freezing point of water. Clouds and fog are made up of tiny droplets of water. National Science Education Standards (Content Standards: K-4, National Academy of Sciences) Earth and Space Science - Content Standard D As a result of their activities in grades K-4, all students should develop an understanding of: Changes in Earth and Sky • Weather changes from day to day and over the seasons. Weather can be described by measurable quantities, such as temperature, wind direction and speed, and precipitation. Science and Technology - Content Standard E As a result of their activities in grades K-4, all students should develop: Understanding about Science and Technology • People have always had questions about their world. Science is one way of answering questions and exploring the natural world. Page 4 Weather on the Move Visual Learning Company 1-800-453-8481 Student Learning Objectives Upon viewing the video and completing the enclosed student activities, students will be able to do the following: • Describe an air mass as a large region of the atmosphere throughout which the air has the same general properties. • Explain that the characteristics of an air mass are associated with the location in which it was formed. • Differentiate between warm fronts and cold fronts, and contrast the types of weather they often create. • Explain the general characteristics of a hurricane, and describe how a tropical storm becomes a hurricane. • Summarize some of the effects a hurricane can have when it hits land, including wind damage, storm surges, and high waves. • Using a diagram, explain how a thunderstorm forms. • Explain the causes of both lightning and thunder. • Describe a few of the key safety procedures to follow in a thunderstorm. • Identify a tornado as a spinning, funnel-shaped cloud with very low pressure at the bottom. • Contrast two different low pressure systems – hurricanes and tornadoes. Describe what makes these storms similar and different from each other. Visual Learning Company 1-800-453-8481 Weather on the Move Page 5 Assessment Preliminary Test (p. 14-15): The Preliminary Test is an assessment tool designed to gain an understanding of students’ preexisting knowledge. It can also be used as a benchmark upon which to assess student progress based on the objectives stated on the previous pages. Post-Test (p. 16-17): The Post-Test can be utilized as an assessment tool following student completion of the program and student activities. The results of the Post-Test can be compared against the results of the Preliminary Test to assess student progress. Video Review (p. 18): The Video Review can be used as an assessment tool or as a student activity. There are two sections. The first part contains questions displayed during the program. The second part consists of a five-question video quiz to be answered at the end of the video. Page 6 Weather on the Move Visual Learning Company 1-800-453-8481 Introducing the Program Before showing the video program, ask students to describe some of the different types of weather they experience during the course of a year. For example, they might describe winter weather as cold and wet. Summer weather might be described as hot and dry. Write their descriptions of weather along with the corresponding time of year on the board. Explain to students that much of the weather they experience is influenced by large air masses which either originate where they live, or move from another location. Tell students to pay close attention to the program to learn more about air masses. Next, ask the class the types of extreme weather events they have experienced or heard about. Have several volunteers describe their experiences with different types of storms, such as thunderstorms, tornadoes, or hurricanes. Make a list on the blackboard of the weather events the class describes. Tell students to pay close attention to the video to learn more about severe weather. Program Viewing Suggestions The student master “Video Review” (p.18) is provided for distribution to students. You may choose to have your students complete this Master while viewing the program or do so upon its conclusion. The program is approximately 14-minutes in length and includes a five-question video assessment. Answers are not provided to the video assessment in the video, but are included in this guide on page 12. You may choose to grade student quizzes as an assessment tool or to review the answers in class. The video is content-rich with numerous vocabulary words. For this reason you may want to periodically stop the video to review and discuss new terminology and concepts. Visual Learning Company 1-800-453-8481 Weather on the Move Page 7 Video Script 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. Page 8 Have you ever been out in a strong wind, ...or experienced a blizzard? Or have you been startled by the flash of lightning and the roar of thunder? All these are examples of the powerful forces of weather. From the torrential downpour of rain. . . . . . and the hard hitting pellets of a hail storm. . . . . .to the awesome wind and rain of a hurricane, weather is continually unleashing its energy throughout the world. What causes different types of weather? How are storms created? And what are some of the various kinds of weather systems? During the next few minutes we are going to explore these questions. . . . . . and others as we investigate weather on the move. Graphic Transition – Air Masses Maybe you have been outside on a hot, humid day. . . . . . when all you wanted to do was go swimming. And then the next day, amazingly, the weather was cool and clear with low humidity. How could the weather be so different on these two days? The answer to this question has to do with something called air masses. An air mass is a large region of the atmosphere in which the air throughout it has the same general properties. An air mass gets its characteristics from the area over which it is formed. For example, an air mass formed over the warm, dry desert of the Southwest has the characteristics of being dry and warm. You Decide! What are the general characteristics of an air mass formed over the Gulf of Mexico? An air mass formed over the Gulf of Mexico tends to be warm and moist. While air masses formed over the North Atlantic tend to be cool and moist. . . . . . as are those formed off the coast of Canada and Alaska. Cold, dry air masses in the northern hemisphere, originate in higher latitudes. These types of air masses are responsible for much of the bitter cold weather southern Canada and the northern United States experience in winter months. So as you can see, there are different types of air masses possessing characteristics of the areas over which they form. As air masses move, they bring the characteristics of the air from which they form with them. Air masses play a big role in creating the weather we experience. Graphic Transition - Fronts Perhaps you have been outside on a pleasant summer day when. . . Weather on the Move Visual Learning Company 1-800-453-8481 Video Script 33. . . . all of a sudden the sky darkens, the air cools, and the wind picks up. And then it starts to pour. What causes this sudden change? 34. This sort of weather may be caused by a passing front. 35. What are fronts? 36. When two air masses meet they usually do not mix too well. 37. Instead, a boundary between the two air masses forms. This boundary is called a front. 38. There are several different types of fronts. Let’s discuss two of them – cold fronts and warm fronts. 39. A warm front is formed when a moving warm air mass meets a cold air mass. 40. You Predict! What will happen when warm, less dense air meets a cooler air mass? 41. In a warm front, a moving warm air mass meets and overrides a cooler air mass. 42. The less dense warm air moves over the denser, cooler air. 43. Warm fronts generally bring steady, light precipitation. . . 44. . . . followed by warm weather. 45. In a cold front, a cooler, denser air mass moves into and under a warmer, less dense air mass. 46. Cold fronts can move quickly. They may cause heavy rain, snow, and even violent thunderstorms. 47. Graphic Transition - Hurricanes 48. The damage to these houses is the result of a powerful hurricane named Charley. In August of 2004, hurricane Charley. . . 49. . . . tore roofs off buildings, . . . 50. . . . leveled trees, . . . 51. . . . and caused tremendous property damage, forcing people to lose their homes, businesses, and possessions. 52. A year later in August of 2005, one of the most devastating hurricanes to ravage North America struck the city of New Orleans and the neighboring Mississippi coast. 53. A massive hurricane called Katrina turned out to be the costliest U.S. hurricane on record and the deadliest U.S. hurricane since 1928. 54. In all, Hurricane Katrina took the lives of at least 1,300 people, . . . 55. . . . and caused at least $80 billion in damage. 56. Hurricanes are large, swirling storms centered around very low pressure. 57. They form over warm tropical waters near the equator typically from June through November. 58. This is a satellite image of a hurricane. 59. You Observe! Is the hurricane rotating in a clockwise or counterclockwise direction? 60. This hurricane, like other hurricanes in the northern hemisphere, is rotating in a counterclockwise direction. 61. A hurricane gets its energy from moisture evaporated off warm ocean waters. Visual Learning Company 1-800-453-8481 Weather on the Move Page 9 Video Script 62. As this air rises, clouds form, and more and more air is drawn into the system. 63. As the storm system builds, winds begin to spin in toward the areas of low pressure. 64. At first, a tropical depression forms with winds from 37 to 63 kilometers per hour, or 23 to 39 miles per hour. 65. Then a tropical storm forms with winds up to 119 kilometers per hour, or about 70 miles per hour. 66. When the winds get stronger, the tropical storm grows into a hurricane. 67. Winds may reach speeds of 300 kilometers, or 180 miles per hour. 68. Winds this strong can blow out windows, and drive debris through buildings and trees. 69. When a hurricane comes ashore it often brings high waves and severe flooding. 70. In many cases a wall of water called a storm surge accompanies a hurricane near the coast. 71. In the case of hurricane Katrina the storm surge was up to 9 meters, or 30 feet high in some places, smashing coastal properties with a wall of water. 72. For these reasons people living in the path of a strong hurricane are instructed to evacuate to a safe place before a hurricane reaches landfall. 73. Graphic Transition – Thunderstorms and Tornadoes 74. Perhaps you have been outside on a warm summer afternoon. . . 75. . . . and noticed the sky darken with gray clouds. 76. In the distance maybe you heard the low rumble of thunder. 77. As the dark clouds approached, you suddenly saw a flash of lightning, . . . 78. . . . and a couple of seconds later you heard the loud clap of thunder and suddenly rain poured down. You experienced a thunderstorm. 79. What factors are responsible for the creation of thunderstorms? 80. Thunderstorms are large violent clouds which produce heavy rain, strong winds, lightning, and thunder. 81. Thunderstorms begin to form when warm, moist air rises rapidly in an unstable atmosphere. 82. When this happens, large moisture-rich cumulus clouds form. 83. As warm, moist air continues to rise, these clouds grow and darken to form cumulonimbus clouds. 84. Within these clouds, in processes not completely understood, swirling winds create a build-up of static electricity which is suddenly released as a bolt of lightning. Lightning bolts can leave the cloud and hit objects on the ground. 85. A single lightning bolt may contain millions of volts of electricity. 86. The loud bang you hear as thunder is the result of air being superheated to a temperature as high as 30,000 degrees Celsius. This causes the air to expand rapidly, creating an explosive roar. Page 10 Weather on the Move Visual Learning Company 1-800-453-8481 Video Script 87. 88. 89. 90. Hundreds of people are hit by lightning each year, with many losing their lives. Do not go outside in a thunderstorm. If you are outside, seek safe shelter immediately. Conditions which lead to the development of thunderstorms may also create very powerful localized storms called tornadoes. 91. A tornado is a spinning funnel-shaped cloud containing very low pressure at its center. 92. When tornadoes touch the ground they act like a giant vacuum cleaner, sucking up large objects. 93. The length of a tornado’s path of destruction varies, but it averages about 8 kilometers in length, and about 10 to 60 meters wide, lasting only a few minutes. 94. The winds of a tornado range from 120 kilometers per hour to as high as 500 kilometers per hour! 95. About 75% of the world’s reported tornadoes occur in the United States with the majority occurring in the shaded area seen here, referred to as Tornado Alley. 96. The safest place to be during a tornado is in the basement of a strong building. 97. Graphic Transition – Summing Up 98. During the past few minutes we have explored some of the fascinating features of weather on the move. 99. We discussed the nature of different kinds of air masses, and some ways they influence our weather. 100. And we investigated how warm fronts and cold fronts form when air masses meet. 101. The awesome power of hurricanes, their formation, and movement was highlighted. 102. High intensity weather phenomena including thunderstorms and tornadoes were also investigated. 103. So the next time you notice the weather changing. . . 104. . . . see a flash of lightning, . . . 105. . . . or read about a tornado, think about some of the things we have discussed during the past few minutes. 106. You just might think about weather on the move a little differently. 107. Graphic Transition – Video Assessment Fill in the blanks to complete the sentence. Good luck, and let’s get started. 1. An air __________ is a large region of air having the same general properties. 2. A __________ is the boundary between two air masses. 3. The passing of a __________ front often produces thunderstorms in the summer. 4. This is a satellite image of a __________. 5. A tornado consists of a funnel cloud containing very __________ pressure. Answers can be found on page 12 Visual Learning Company 1-800-453-8481 Weather on the Move Page 11 Answer Key to Student Assessments Pre-Test (p. 14-15) 1. b - warm and moist 2. d - a front 3. a - precipitation 4. c - low pressure 5. d - counterclockwise 6. a - a storm surge 7. b - lightning 8. b - indoors 9. c - a few minutes 10. a - Tornado Alley 11. false 12. true 13. false 14. true 15. true 16. An air mass is a large region of the atmosphere throughout which the air has the same general properties. 17. A front is the boundary between two air masses. 18. Hurricanes form over warm ocean waters when winds begin to spin around an area of low pressure. 19. When a thunderstorm approaches, winds increase, the sky darkens, and rain may begin to fall. 20. A tornado is a funnel-shaped cloud spinning around an area of extreme low pressure. Post-Test (p. 16-17) 1. a - Tornado Alley 2. d - counterclockwise 3. c - a few minutes 4. b - lightning 5. d - a front 6. b - indoors 7. c - low pressure 8. b - warm and moist 9. a - a storm surge 10. a - precipitation 11. true 12. true 13. false 14. false 15. true 16. Hurricanes form over warm ocean waters when winds begin to spin around an area of low pressure 17. A tornado is a funnel-shaped cloud spinning around an area of extreme low pressure. 18. A front is the boundary between two air masses. 19. An air mass is a large region of the atmosphere throughout which the air has the same general properties. 20. When a thunderstorm approaches, winds increase, the sky darkens, and rain may begin to fall. Video Review (p. 18) 1. An air mass formed over the Gulf of Mexico tends to be warm and moist. 2. This is called a warm front and generally warm fronts bring steady, light precipitation followed by warm weather. 3. The hurricane is rotating in a counterclockwise direction as do all hurricanes in the northern hemisphere. Page 12 Weather on the Move 1. An air mass is a large region of air having the same general properties. 2. A front is the boundary between two air masses. 3. The passing of a cold front often produces stormy weather. 4. This is a satellite image of a hurricane. 5. A tornado consists of a funnel cloud containing very low pressure. Visual Learning Company 1-800-453-8481 Answer Key to Student Activities Vocabulary (p. 19 ) 1. air mass 2. front 3. hurricane 4. tropical storm 5. storm surge 6. thunderstorm 7. lightning 8. thunder 9. tornado 10. cumulonimbus Writing Activity (p. 20) An air mass is a large region of air with uniform characteristics. Air masses possess the same general temperature and moisture content of the area where they form. The border between two air masses is called a front. Hurricanes are large low pressure storms with high winds formed over warm ocean waters. At the center of a hurricane is an area of intense low pressure. Tornadoes, consist of fast spinning, funnel-shaped clouds, containing very low pressure. The most common type of extreme storms are thunderstorms. When static electricity inside thunder clouds is suddenly released, lightning forms. The bang of thunder afterward is caused by the rapid heating of air. In Your Own Words (p. 20) 1. An air mass is a large region of air with the same general characteristics throughout. 2. A hurricane is a large low pressure storm that possesses high winds and rain. 3. Thunder is caused by air particles rapidly expanding after being superheated by a bolt of lightning. Visual Learning Company 1-800-453-8481 Model of a Front (p. 21-22) 1. The blue cold water represents a cold air mass. The surrounding warm water represents a warm air mass. 2. The blue, cold water moved into and under the warm water. 3. The blue water moved this way because it is denser than the warm water. 4. This activity is a model of a cold front where a cooler, denser air mass moves into and under a warmer, less dense air mass. 5. This type of front can move quickly and may cause precipitation or even violent thunderstorms. Naming Hurricanes (p. 23-24) 1. Tropical storms and hurricanes are given names because names help people differentiate between the unique characteristics of each storm. 2. Storms that occur in the northern Atlantic Ocean are named by the United States National Hurricane Center. 3. Storms are named when they become tropical storms, that is, when wind speeds reach 64 to 119 kilometers per hour, (about 40 to 70 miles per hour). 4. Some storm names are not reused when a storm causes a particularly large amount of damage. 5. The sixth storm in 2009 will be named Fred. 6. Answers will vary depending on student names. Additional lists of hurricane names are available through the U.S. National Hurricane Center. Thunderstorm Safety Tips (p. 25) 1. When a thunderstorm approaches, the first thing you should do is find shelter inside a sturdy building. If a sturdy building is not available, seek shelter in a car. 2. You should avoid being in or on the water during a thunderstorm because water readily conducts electricity. This means you could be shocked if you are in or around water when lightning strikes. 3. It is a good idea to turn off or unplug electrical appliances during a thunderstorm because there is a possibility of a power surge or outage occurring. Such surges or outages have the potential to destroy the circuitry in electrical appliances. Weather on the Move Page 13 Pre-Test Name Circle the best answer for each of the following questions. 1. An air mass formed in the Caribbean would have the following characteristics: a. cold and dry b. warm and moist c. cold and moist d. warm and dry 2. The boundary between two air masses is called: a. cold b. warm c. a storm d. a front 3. A warm front often brings steady, light: a. precipitation b. earthquakes c. waves d. condensation 4. What is found at the center of both a hurricane and a tornado? a. sleet b. high pressure c. low pressure d. cold weather 5. In the northern hemisphere, in what direction do hurricanes rotate? a. left b. clockwise c. right d. counterclockwise 6. The wall of water that sometimes accompanies a hurricane near the coast is called: a. a storm surge b. a ripple c. rain d. lightning b. lightning c. a hurricane d. rain 7. Thunder follows: a. a storm 8. Where is the safest place to be during a thunderstorm? a. in the water b. indoors c. outside d. under a tree 9. In a specific location a tornado generally lasts: a. many hours b. two seconds c. a few minutes d. several days 10. In North America, the majority of tornadoes occur in an area referred to as: a. Tornado Alley b. Sonoran Desert c. California d. Canada Weather on the Move Visual Learning Company Page 14 Pre-Test Name Write true or false next to each statement. 11. An air mass always gets its characteristics from the ocean. 12. Cold fronts tend to cause more extreme weather than warm fronts. 13. Hurricanes are usually formed over land. 14. Cumulonimbus clouds indicate a thunderstorm may be possible. 15. A tornado acts like a vacuum cleaner, sucking up objects and tearing up debris in its path. Write a short answer for each of the following. 16. What is an air mass? 17. What is a front? 18. How and where do hurricanes form? 19. Describe how the weather changes as a thunderstorm approaches. 20. What is a tornado? Weather on the Move Visual Learning Company Page 15 Post-Test Name Circle the best answer for each of the following questions. 1. In North America, the majority of tornadoes occur in an area referred to as: a. Tornado Alley b. Sonoran Desert c. California d. Canada 2. In the northern hemisphere, in what direction do hurricanes rotate? a. left b. clockwise c. right d. counterclockwise 3. In a specific location a tornado generally lasts: a. many hours b. two seconds c. a few minutes d. several days b. lightning c. a hurricane d. rain 4. Thunder follows: a. a storm 5. The boundary between two air masses is called: a. cold b. warm c. a storm 6. Where is the safest place to be during a thunderstorm? a. in the water b. indoors c. outside d. a front d. under a tree 7. What is found at the center of both a hurricane and a tornado? a. sleet b. high pressure c. low pressure d. cold weather 8. An air mass formed in the Caribbean would have the following characteristics: a. cold and dry b. warm and moist c. cold and moist d. warm and dry 9. The wall of water that sometimes accompanies a hurricane near the coast is called: a. a storm surge b. a ripple c. rain d. lightning c. waves d. condensation 10. A warm front often brings steady, light: a. precipitation b. earthquakes Weather on the Move Visual Learning Company Page 16 Post-Test Name Write true or false next to each statement. 11. Cold fronts tend to cause more extreme weather than warm fronts. 12. A tornado acts like a vacuum cleaner, sucking up objects and tearing up debris in its path. 13. Hurricanes are usually formed over land. 14. An air mass always gets its characteristics from the ocean. 15. Cumulonimbus clouds indicate a thunderstorm may be possible. Write a short answer for each of the following. 16. How and where do hurricanes form? 17. What is a tornado? 18. What is a front? 19. What is an air mass? 20. Describe how the weather changes as a thunderstorm approaches. Weather on the Move Visual Learning Company Page 17 Video Review Name While you watch the video, answer these questions: You Decide! 1. What are the general characteristics of an air mass formed over the Gulf of Mexico? You Predict! 2. What will happen when warm, less dense air meets a cooler air mass? You Observe! 3. Is the hurricane rotating in a clockwise or counterclockwise direction? After you watch the video, test your knowledge with these questions. 1. An air ___________ is a large region of air having the same general properties. 2. A ______________ is the boundary between two air masses. 3. The passing of a ___________ front often produces stormy weather. 4. This is a satellite image of a ______________________ . 5. A tornado consists of a funnel cloud containing very ______ pressure. Weather on the Move Visual Learning Company Page 18 Vocabulary Name Use these words to fill in the blanks next to the sentences below. Words thunder hurricane tornado lightning air mass storm surge thunderstorm front tropical storm cumulonimbus 1. A large region of air possessing the same general properties. 2. The boundary between two air masses. 3. A large, swirling storm centered around very low pressure. 4. A smaller low pressure system that may develop into a hurricane. 5. A wall of ocean water created by a hurricane near the coast. 6. Small, intense weather system that produces heavy rain, strong winds, lightning, and thunder. 7. The release of built-up static electricity during a thunderstorm. 8. The loud bang caused by superheated air expanding rapidly from a lightning bolt. 9. A spinning, funnel-shaped cloud containing very low pressure at its bottom. 10. Large, moisture rich, dark clouds formed by warm, moist air rising rapidly which have the potential to produce lightning. Weather on the Move Visual Learning Company Page 19 Writing Activity Words tornadoes front thunder Name air mass hurricanes lightning thunderstorms Use the correct word from above to complete the sentences in the following paragraph. An _________ ___________ is a large region of air with uniform characteristics. Air masses possess the same general temperature and moisture content of the area where they form. The border between two air masses is called a _____________ . _____________________ are large low pressure storms with high winds formed over warm ocean waters. At the center of a hurricane is an area of intense low pressure. _________________, consist of fast spinning, funnel-shaped clouds, also containing very low pressure. The most common type of extreme storms are _____________________ . When static electricity inside thunder clouds is suddenly released, ____________________ forms. The bang of __________________ afterward is caused by the rapid heating of the air. In Your Own Words 1. What is an air mass? 2. What is a hurricane? 3. What causes thunder? Weather on the Move Visual Learning Company Page 20 Model of a Front Name Background: If you live in a place that has different kinds of weather throughout the course of the year, maybe you have wondered what causes the weather to change. One of the factors responsible for changing weather is the arrival of different air masses. An air mass is a large region of the atmosphere in which the air throughout it has the same general properties. An air mass gets its characteristics from the area over which it is formed. For example, an air mass formed over the warm, dry desert of the Southwest has the characteristics of being dry and warm. An air mass formed over the Gulf of Mexico tends to be warm and moist. Air masses formed over the North Atlantic tend to be cool and moist like those formed off the coast of Canada and Alaska. Cold, dry air masses in the northern hemisphere originate in higher latitudes. As air masses move, they bring the characteristics of the air from which they form with them. Perhaps you have been outside on a pleasant summer day when all of a sudden the sky darkens, the air cools, and the wind picks up. And, then it starts to pour. What causes this sudden change? This sort of weather may be caused by a passing front. What are fronts? When two air masses meet they usually do not mix well. Instead, a boundary between the two air masses forms. This boundary is called a front. There are several different types of fronts. A warm front is formed when a moving warm air mass meets a cold air mass. In a warm front, a moving warm air mass meets and overrides a cooler air mass. The less dense warm air moves over the denser, cooler air. Warm fronts generally bring steady, light precipitation followed by warm weather. In a cold front, a cooler, denser air mass moves into and under a warmer, less dense air mass. Cold fronts can move quickly and may cause heavy rain, snow, and even violent thunderstorms. In this activity you will create a model of a cold front. Materials: a small aquarium or a water-tight see-through container, six ice cubes, ziploc bag, blue food coloring, thumbtack, hot water Activity: 1. Carefully drop five drops of blue food coloring in the ziploc bag. Seal the bag and then gently shake it. Allow the bag to sit for a few minutes. 2. Working in groups of two to three students, obtain the materials listed above. 3. Fill the container with about 20 centimeters of hot water. 4. Place the six ice cubes in the ziploc bag. 5. Insert about 5 - 8 holes in the bottom of the ziploc bag using the thumbtack. Be careful not to injure yourself when doing this. 6. Gently immerse the bag in one end of the container full of water until it touches the bottom. 7. Hold the bag down for several minutes and observe the pattern of the blue-colored water as it seeps out of the bag. 8. Answer the questions on the next page. Weather on the Move Visual Learning Company Page 21 Model of a Front Cont. Name Questions: 1. Describe the two different air masses modeled in this activity. 2. Describe how the blue, cold water moved. 3. Why did the blue water move the way it did? 4. What type of front did this activity model? 5. In real-life, what types of weather is common along this type of front? Weather on the Move Visual Learning Company Page 22 Name That Hurricane Name Directions: Read the following information and then answer the questions on the next page. Background: The names Katrina, Rita, and Charley might be familiar to you, and not because they are the names of your friends or family. You probably have heard these terms because they are the names of recent hurricanes that devastated parts of the Caribbean and North America. Why do storms have names? A name is a useful tool for remembering a specific person or thing. Because each tropical storm and hurricane has its own unique characteristics, giving each storm a name helps people differentiate between storms. It also makes the storms sound important. This is a good practice because hurricanes are very dangerous, and should not be ignored. Storms that form in the northern Atlantic Ocean are named by the United States National Hurricane Center. Storms are not named until they have reached tropical storm status. A tropical storm has winds of 64 to 119 kilometers per hour, (about 40 to 70 miles per hour). Hurricane season in the Atlantic lasts from June 1st through November 30th. During this time, there are usually six to fourteen named storms. The U.S. National Hurricane Center names storms using first names. There are six lists that are recycled every six years. In each list, the names are arranged alphabetically. After each male name there is a female name, and vice versa. When a storm causes a large amount of damage, its name is not reused. For example, the name “Katrina” will not be recycled because of the tragedy Hurricane Katrina caused in 2005 along the coast of the Gulf of Mexico. As of 2005, there have been 68 names that have been retired from use. More names were retired in 2005 than ever before, five, including: Dennis, Katrina, Rita, Stan, and Wilma. Because tropical storms and hurricanes occur in both the Atlantic and Pacific oceans, different countries have different naming schemes for storms that occur in their waters. However, the use of rotating alphabetical lists of human first names is the most common basis for the systems. To find more information about the six lists of names used by the U.S. National Hurricane Center, as well as lists of storm names used by other countries, you can look up the information at the library, or on the internet. Weather on the Move Visual Learning Company Page 23 Name That Hurricane Name Questions: 1. Why are tropical storms and hurricanes given names? 2. Who names storms in the northern Atlantic Ocean? 3. When are storms named? 4. When are some storm names not reused? Hurricane Names 2007 Andrea Barry Chantal Dean Erin Felix Gabrielle 2008 Arthur Bertha Cristobal Dolly Edouard Fay Gustav 2009 Ana Bill Claudette Danny Erika Fred Grace Humberto Ingrid Jerry Karen Lorenzo Melissa Noel Olga Pablo Rebekah Sebastian Tanya Van Wendy Hanna Ike Josephine Kyle Laura Marco Nana Omar Paloma Rene Sally Teddy Vicky Wilfred Henri Ida Joaquin Kate Larry Mindy Nicholas Odette Peter Rose Sam Teresa Victor Wanda 5. What will the sixth storm in 2009 be named? 6. Has there ever been, or will there be, a storm with your name? Weather on the Move Visual Learning Company Page 24 Thunderstorm Safety Tips Name Directions: Read the following information and then answer the questions. Background: Thunderstorms are the most common form of extreme weather. You are probably familiar with the characteristics of a thunderstorm. Lightning, high winds and hail associated with thunderstorms can be very dangerous. In this activity you will learn some important safety precautions to take during a thunderstorm. • If a thunderstorm is approaching, go inside a sturdy building. A house is much safer than a lean-to or a tree house. It is safer to seek shelter inside a car than to stay outside. • If you cannot find shelter, move to lower ground. Stay away from tall, isolated objects like trees or poles. Remember that lightning is more likely to strike taller objects. • Do not swim, be in a boat, or take shelter on the water during a thunderstorm. Water is a good conductor of electricity. Therefore, you are more likely to receive a shock if you are touching water when lightning strikes. If you are in a boat, seek landfall immediately. • Try not to use the telephone or other electrical devices. If lightning were to strike your house, these items could conduct electricity and give you an electric shock. • Turn off, or better yet unplug any computers or other electrical appliances in the event of power surges or outages. Such surges or outages have the potential to destroy the circuitry in electrical appliances. • If power lines have fallen, do not touch them. Have an adult call the power company so they can promptly come to fix the lines. Questions: 1. If the sky darkens and you hear thunder in the distance, what is the first thing you should do? 2. Why should you avoid being in or on the water during a thunderstorm? 3. Why is it a good idea to turn off or unplug electrical appliances during a thunderstorm? Weather on the Move Visual Learning Company Page 25