3-5 How Do Tornadoes Form

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LESSON PLAN 1

How Do TornadoesForm?The word tornado comes from the Spanish wordtronada, 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 kilo-

meters) per hour or more.

Key Terms and Concepts

air pressure

anvil cloud

atmospherecondense

cumulonimbus cloud

cumulus cloud

downdraft

Purpose

To introduce students to the science of tornadoes

Objectives

The students will UseA 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

bookfiction or nonfictionthat 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)

UseHail Makerto 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)

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Tornado Science

1Masters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form?

Copyright 2007 The American National Red Cross

Visit the American Red Cross Web site

at www.redcross.org/disaster/masters

Enhanced Fujita

Scale

funnel cloudhail

mesocyclone

supercell

thunderhead

tornado

updraft

vertical wind shearvortex


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LESSON PLAN 1

How Do TornadoesForm?

Set up, present and discuss observations of weather demonstrations,

using the activity sheets Wind Maker, Storm Cloud, Tornado in a

Bottle andWind 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






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LESSON PLAN 1


3

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

Tornado Talk

SET UP 45 minutes CONDUCT two 45-minute classes

Language Arts: Writing and Research; Science: Earth Science and

Physical Science

1. Display the classroom library of materials on the weather.

Include a computer or computers with access to the Internet.

2. DistributeA 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 defi-

nitions for each of the words on the chalkboard or large

poster paper.

Definitions forA Tornado Is Born

anvil cloud: the upper portion of a cumulonimbus cloud that flattens

spreads out, sometimes for hundreds of milesatmosphere: 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 heavyrains and violent wind gusts

front: the boundary between two air masses with differing characteris-

tics, 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 winds 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




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LESSON PLAN 1


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.

Answers toA 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 orcumulonimbus

(kyu-mya-lo-NIM-buhs) cloud, grows, topped by an anvil cloud. The

thunderheads most likely to cause tornadoes are those that form alongand 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 amesocyclone (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.






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LESSON PLAN 1


5

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.

Resources:Animations of Tornado Formation

Prentice Hall, Geoscience Animations

http://esminfo.prenhall.com/science/geoanimations/animations/

Tornadoes.html

MSNBC: Birth of a Tornadohttp://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... Natures 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, entitledA Tornado Is Born. Their books can be fiction or non-

fiction, 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

tornados approach did they observe?

Briefly, discuss what students learned at home. Challenge them to work

together to tie clues to the reality of a tornados formation. For example,

why might hail be a good clue to the possible approach of a tornado?

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.




TEACHING NOTE The Hail Makerdemonstration takes about four hours to set up.


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LESSON PLAN 1


1. DistributeHail Makerand the needed materials to student groups.

2. Have the groups complete the demonstration and work together to

answer the questions on the activity sheet.

Answers toHail 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 fromA

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 becomeheavy 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.





Materials

Freezer, for use by all the

groups

For each group:

Hail Maker

Scissors

Wax paper

Saucer

Eyedropper

Cold tap water

Black construction paper

Desk lamp

Paper towel

Magnifying lens


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LESSON PLAN 1


7

Making Weather

SET UP 45 minutes CONDUCT two 45-minute classes

Science: Earth Science and Inquiry

1. Introduce the activity by discussing with students the importance ofdemonstrations to the understanding of difficult concepts. Explain that

the demonstrations will help them better understand the physics behind

tornado development.

2. Divide the students into four teams and assign one weather demonstra-

tion to each team. Help the teams gather the materials they need and, if

necessary, guide them through the demonstrations within their groups.




TEACHING NOTE Tornado Talk, the first activity in Lesson Plan 1, describes the

basics of tornado formation. Students will better understand Making Weather ifthey complete Tornado Talk first.

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 fourdemonstrations:

Wind Maker

Wind Maker

3 (8 cm) paper circle cut into a spiral

10 (25 cm) piece of thread

Heat source (light bulb)

Storm Cloud

Storm Cloud

Clear, plastic sweater box or similarcontainer, 8 x 8 x 12 (20 x 20 x 30 cm)

Water (room temperature)

Heated milk, about 140 F (78 C) meas-ured on a candy thermometer

Clean baby food jar

Plastic wrap

Rubber band

Sharp object, such as the end of a paperclip

Wind Shear

Wind Shear

Toilet tissue tube

2 hardbound books

Tornado in a Bottle

Tornado in a Bottle

Two 2-liter soda bottles with caps

Hammer and a 2 (5 cm) nail Scissors

Balloon

Food coloring

About 2 quarts (2 liters) of water


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LESSON PLAN 1


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 teams

findings and analysis with the class as a whole.

Team 1Wind MakerAnswer

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 2Storm 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 waters 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 thunder-

storm cloud, frequently accompanied by heavy rains, lightning,

thunder and, sometimes, hail, tornadoes or strong winds.

Team 3Wind 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.






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LESSON PLAN 1


9

Team 4Tornado 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 MakerandStorm 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 circumstanceswarm, surface air and cooler, drier airaloftresult in thunderheads? What if the warm air is dry? Would

thunderclouds form? Why or why not?

Answer fromStorm 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 mesocy-

clone. At first, the rotating air is horizontal. What probably causes it

to lift up and become vertical?




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.


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LESSON PLAN 1


Answer from Wind Shearand 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 Makerand Tornado in a Bottle

The mesocyclone draws ground-hugging air up into itself, where it

expands and cools, condensing and, thus, building the cloud basedownward 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 thisenergy 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 mines 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 andtook 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.





Materials

The Enhanced Fujita Scale of

Tornado Intensity (Linking

Across the Curriculum)


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LESSON PLAN 1


11

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 furtherdiscussion on any differences in class opinion and on the kind of informa-

tion they would need to make a more definitive classification.

Language Arts: Reading

Lead a discussion of the impossible situations the students have seen in

fictional accounts of tornadoesfrom The Wizard of Ozto Twister. What

scientific facts are misinterpreted or misrepresented? Can misinformation

be dangerous? Explain.




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

.htmlfor text.


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A Tornado Is BornPage 1 of 3

Name ________________________________________________________________________

A TORNADO IS BORNMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form

Copyright 2007 The American National Red Cros



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:


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Step 2: Below is a description of the way tornadoes form. Some of the words aremissing. Use the words from Step 1 to complete the description. Then, draw a story-

board 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 kilo-

meters).

On warm days, the air near the ground is much warmer than it is at higher eleva-tions. 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

_____________.


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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 awhirling cloud appears. This cloud is called a _______________.

Some funnel clouds hang straight down from the storm cloud. Others stretch side-

ways through the sky. A funnel cloud may dip down and retract into the mesocy-

clone, or it may touch the ground. If it touches the ground, the funnel cloud is called

a _______________.


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Directions: Gather the following materials andfollow 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 Do1. 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 itwith 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.)

Hail MakerPage 1 of 2

Name ________________________________________________________________________

HAIL MAKERMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form





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Hail MakerPage 2 of 2

HAIL MAKERMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




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.


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Wind MakerPage 1 of 2

Name ________________________________________________________________________

WIND MAKERMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




Directions: Gather the following materials and follow the steps below toillustrate 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?


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Wind MakerPage 2 of 2

WIND MAKERMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




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 movefarther apart.)


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Storm CloudPage 1 of 2

Name ________________________________________________________________________

STORM CLOUDMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




Directions: Gather the following materials and follow the steps below toillustrate 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 tightly3. 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


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Storm CloudPage 2 of 2

STORM CLOUDMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




7. Illustrate or describe what happens when the milk begins to cooland sink.

What You DiscoveredHow does this demonstration apply to thunderstorm cloud formation?

Challenge: Use the terms anvil cloud, updraft, virga, andmammatus

clouds in your description.


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Wind ShearPage 1 of 1

Name ________________________________________________________________________

WIND SHEARMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form


Directions: Gather the following materials and follow the steps below to illustratewind 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 books2. 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 lowerwinds, 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?


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Tornado in a BottlePage 1 of 2

Name ________________________________________________________________________

TORNADO IN A BOTTLEMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




Directions: Gather the following materials and follow the steps below to illustratesome 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 in

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.


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Tornado in a BottlePage 2 of 2

TORNADO IN A BOTTLEMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




What You DiscoveredWhat part(s) of a tornado does this demonstrate?

How does it compare to real tornado formation?


24/25

The Enhanced Fujita Scaleof Tornado IntensityPage 1 of 2

Name ________________________________________________________________________

THE ENHANCED FUJITA SCALE OF TORNADO INTENSITYMasters of Disaster Tornadoes, Tornado Science, Lesson Plan 1/How Do Tornadoes Form




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 Administrations 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 comparesimilar items.


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The Enhanced Fujita Scaleof Tornado IntensityPage 2 of 2

THE ENHANCED FUJITA SCALE OF TORNADO INTENSITY

EF Scale NumberWind Speed(3-second gusts) Description of Damage

EF0Light damage

65 to 85 mph(105137 km/h)

Causes some damage to siding, shingles

and gutters; breaks branches from trees

and overturns trees with shallow roots

EF1Moderate damage

86 to 110 mph(138177 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

EF2Considerabledamage

111 to 135 mph(178217 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

EF3Severe damage

136 to 165 mph(218266 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

EF4Devastating damage

166 to 200 mph(267322 km/h)

Completely destroys well-built resi-

dences, large sections of school build-

ings and large office buildings; throws

about cars and other large objects;

tosses small objects like missiles

EF5Incredible damage

More than 200 mph(more than 322 km/h)

Causes significant structural deforma-tion 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.

Documents

3-5 How Do Tornadoes Form