Recognize how weather directly affects our lives.
Describe examples of weather folklore.
Create stories to explain weather phenomenon.
Bryan, Ashley. The Story of Lightning and Thunder. New York: Atheneum, 1993. A Nigerian weather folktale.
Davis, Hubert. A January Fog Will Freeze a Hog and Other Weather Folktales. New York: Crown, 1977. Thirty sayings, their origins and what they mean.
Hiscock, Bruce. The Big Storm. New York: Atheneum, 1993. Hiscock follows the 1982 April blizzard that paralyzed the East Coast from its beginnings in the Northwest through all of its changes as tornadoes in Texas to hail in Kentucky, and shows how it affected people.
Kahl, Jonathan. Weatherwise: Learning About Weather. Minneapolis, Lerner, 1992.
Mayo, Gretchen. Earthmakers' Tales: North American Indian Stories about Earth Happenings. New York: Walker, 1989.
McVey, Vicki. The Sierra Club Book of Weatherwisdom. Boston: Little Brown, 1991. Natural signs of approaching weather changes have been observed by Native Americans and passed on to their children as "weatherwisdom" for generations. McVey tells stories of how this wisdom helped young people predict bad weather and survive in the wilderness.
Milord, Susan. Tales of the Shimmering Sky. Charlotte, VT: Williamson, 1996. Ten folktales from around the world that explain celestial and weather phenomenon.
Suzucki, David. Looking At Weather. New York: Wiley, 1991. How weather affects people's lives and how people affect the weather.
Watson, Benjamin. The Old Farmer's Almanac of Weather and Natural Disasters. New York: Random House, 1995.
Wolff, Barbara. Evening Gray, Morning Red: A Ready-to-Use Handbook
of American Weather Wisdom. New York: Macmillan, 1976. Rhymes, sayings
and signs used to forecast the weather.
Tell the students that this month they will be studying weather. Ask: What is weather? (Sunny, rainy, snowy, hot, humid, windy, cold, stormy, icy--weather is what the air is like around us at any particular time.) Discuss with the students how weather affects their lives. In addition to needing warm clothes and heated buildings in the winter time, remind them that without rainfall, farmers cannot grow their crops. In years of drought (little rainfall) farmers harvest much less and must raise the prices for their crops. We pay these higher prices at the grocery store. Ask: What happens if it rains too much and the storm drains can't handle the water? (flooding and water damage to homes) Discuss what happens sometimes during storms with high winds (Power lines get knocked down and there are power outages--no fans, no refrigerators, no lights, no television.) Discuss how heavy snowfalls in Baltimore change the students' daily routines. Ask students to describe their favorite kind of weather.
Ask: When we look out the window or walk outside, what senses do we use to tell what the weather is like? (Accept all answers. Examples: We know it is raining when we hear raindrops tapping on the window. We know it is windy when we feel it pushing against our skin.
We know it is stormy when we see lightning flash in the sky. We know it has just rained when we smell wet pavement.) Ask: Can our sense of taste tell us anything about what the weather is like? (Accept all answers. Snowflakes on our tongues?)
Tell the children that in the past, people were affected by the weather as much if not more than they are today. Understanding the weather was extremely important and so they used all their senses to try to observe weather patterns. For instance, some sailors noticed that on nights when there was a hazy cloud halo around the moon, there was usually rain the next morning. They passed this information on to other sailors as a rhyme: Ring around the moon, rain before noon. Other sailors heard it and added their own observations. They noticed that if the sunset sky was a glowing red, the seas were usually calm in the morning. However, if the sunrise sky was red, it meant storm on the way. They made this into an easy-to-remember rhyme, too: Red sky at night, sailor's delight. Red sky at morning, sailors take warning. Farmers used their ears to observe this weather pattern: Goose honks high, weather fair. Goose honks low, weather foul. Ask: What do you think that means? (If you hear a goose honking from way up high in the sky, there probably aren't any storm clouds up there and the weather is fair. If the goose is flying low, it is probably avoiding the rain clouds and rain is on the way.)
Sometimes people made up stories to explain weather changes. Ask the students if they ever heard someone say that thunder was the angels moving heavy furniture around in heaven. Ask what other stories they have heard to explain what thunder is. (angels bowling league night, Mother Earth's turn to wash the dishes, Thor walking across the sky with his big boots on, throwing lightning bolts) These stories and the sailors' and farmers' observations are part of what we call weatherlore. Some of it has truth to it and some of it does not. We don't know who came up with the sayings and stories, they have just been handed down by word of mouth for generations. Read aloud The Story of Lightning and Thunder by Ashley Bryan.
Divide the students into groups of four and give each group a slip of paper with a piece of weatherlore. Have the groups imagine who might have come up with the weatherlore. Do they think it has truth to it? Create a story to explain where this piece of weatherlore came from.
Following are some weatherlore suggestions:
If the cows lie down in the field it is going to rain.
When bees are out flying, there will be fair weather. When they stay close to the hive, rain is coming.
Grasshoppers chirp louder and louder the hotter it gets.
Cats wash themselves just before it rains.
When a donkey nods and shakes its head a lot, it means rain is on the way.
Flies bite more if there is a storm coming.
When you hear mice squeaking in the house, the weather is going to change.
If the spiders are making bigger webs, the weather will be dry.
Have the students share their stories with the class.
Tell the students that during their study of weather, they will keep
Weather Journals. Each day they should record their observations about
the weather. Was the morning sunny or cloudy? Were the streets wet from
previous rain? Did the wind blow hard enough to make the flag wave? If
the day was sunny, did they notice a lot of birds flying? Was a puddle
that was there in the morning gone in the afternoon? Perhaps they may notice
some weather patterns and make their own weatherlore.
Fourth Grade - Science - Lesson 2 - Meteorology
Adapted from Teaching Children About Life and Earth Sciences
by Elaine Levenson, p. 64.
Recognize that uneven warming of the Earth causes differences in air temperature and pressure.
Observe how warm air expands and rises.
Build a working thermometer to measure the relative temperature of water,
based on the warm- water-rises principle.
Transparency of Earth's atmosphere (see attached)
Plastic soda bottle, balloon, pan or small bucket of ice water, pan or small bucket of hot water
Transparency of prevailing winds (see attached)
For each group of five: small bucket or container of ice water,
small bucket or container of hot water, small easy-pour container of water
with red food coloring in it, small plastic soda bottle, drinking straw,
wad of clay or playdoh, index card and piece of tape, newspaper to cover
Allaby, Michael. How the Weather Works. Pleasantville, NY: Readers Digest, 1995. While many of the experiments presented here require a lot of adult supervision, the attempt to include an activity to demonstrate each concept is admirable. The color photos of children performing the experiments are extremely helpful.
Ardley, Neil. Science Book of Weather. San Diego: Harcourt, 1992. An excellent and comprehensive book with lucid explanations of weather phenomenon. Highly recommended.
Bower, Miranda. Experiment with Weather. Minneapolis: Lerner, 1994. This introduction to meteorology answers common questions about and offers activities to demonstrate how rainbows, fog, wind and clouds are formed.
Branley, Franklyn. It's Raining Cats and Dogs: All Kinds of Weather and Why We Have It. Boston, Houghton, 1987.
Flint, David C. Weather and Climate. New York: Gloucester, 1991. Simple experiments and information on the composition of the atmosphere. Part of the Hands-On-Science series.
Gardner, Robert. Science Projects About Weather. Hillside, NJ: Enslow, 1994.
Lambert, David. The Weather and Its Work. New York: Facts on File, 1987.
Levenson, Elaine. Teaching Children About Life and Earth Sciences. New York: TAB Books, 1994.
McMillan, Bruce. The Weather Sky. New York: Farrar Straus, 1991.
Morgan, Sally. Weather. New York: Time Life, 1996.
Simon Seymour. Weather. New York: Morrow, 1993. Simon is able to organize complex information on wind currents and the effects of uneven atmospheric warming and present it in a complete narrative rather than in short chapter snippets as it is in other books.
Wyatt, Valerie. Weatherwatch. New York: Addison Wesley, 1990.
Suggestions for how to set up a class weather station and weather record
Suggested Books listed in this lesson contain information and illustrations useful for all lessons in this month's unit on Weather. A few books that focus on special weather events such as hurricanes or include particularly strong chapters on air masses or weather forecasting are
listed with those lessons.
If possible, mount a thermometer outside the classroom window (some
thermometers come with suction cup attachments) and have students record
temperatures twice daily on a chart next to it.
Meteorology is the study of weather and climate. Changes in the Earth's weather are caused by uneven heating. The sun's energy passes through the Earth's atmosphere as visible light and invisible radiation. One third of the energy is reflected back into space. The other two thirds are absorbed and changed into heat. The heat is held in by the Earth's atmosphere. This is called the greenhouse effect. Like a closed-up car on a sunny day, light passes through the windows, is absorbed and heats the inside of the car, but the heat cannot escape. The temperature inside the car rises. The atmosphere holds in heat at night and moderates temperatures on Earth. If we had no atmosphere, our temperatures would be similar to the moon's: 214 degrees Fahrenheit during the day and minus 238 degrees Fahrenheit during the night. In fact, without an atmosphere, Earth would look a lot like the moon--a treeless, oceanless, lifeless hunk of rock. Thanks to Earth's gravity, it is able to hold on to its atmosphere.
Earth's atmosphere is an envelope or blanket of air 434 miles thick with four layers. The outer layer where the atmosphere ends and space begins is called the thermosphere. Gases are very thin in this layer and ultraviolet light heats them to very high temperatures. Meteors burn up in the thermosphere. Under that layer is a much colder layer about 20 miles thick called the mesosphere. Beneath that is a warmer, dry layer, the stratosphere, where the ozone layer--the Earth's protection against excessive ultraviolet radiation--is found. The troposphere, the seven-mile-thick, bottom layer, full of water vapor and dust, is where most of our weather happens. One could say that weather is the state of the atmosphere at a particular place at a particular time. The factors that interact to cause weather are heat energy, air pressure and winds, and moisture.
Because the Earth is a sphere, as the sun's rays pass through Earth's atmosphere, they do not strike a flat surface evenly. The sun's rays hit more directly along the equator and more diffusely at the poles. The uneven heating causes air movements that set weather patterns in motion.
When heated, air molecules spread out and air becomes lighter. Air pressure on the Earth is less. The heated air at the equator rises and moves toward the poles. Cooler air from the poles sinks because it is denser with molecules closer together. It exerts more air pressure and moves toward the equator where it is heated and rises. When the rising equatorial air cools off, it sinks and replaces the cool air moving toward the warmer equator. This exchange of warm and cool air creates winds--air in motion. These global winds do not move north to south and south to north. They are affected by the rotation of the Earth. Earth rotates from west to east at speeds of a thousand miles an hour at the equator and much faster at the poles. Winds in the Northern Hemisphere curve to the right. Winds in the Southern Hemisphere curve to the left. If you could watch the Earth spin, you'd see mountains, oceans, deserts, prairies, canyons, and jungles pass by. The variations in the Earth's surface reflect and absorb the sun's energy unevenly. Polar ice
caps reflect 90% of the sun's energy. Tropical rainforests absorb large
amounts of energy. Oceans capture and hold heat longer than land. This
further uneven heating also causes winds.
One can see that the density or pressure of an air mass is affected
by temperature (heating and cooling). It is also affected by water vapor
and elevation. Air with lots of water vapor in it, of high humidity, exerts
less pressure on the Earth. Air pressure decreases the higher the elevation.
moves from areas of high pressure to areas of low pressure causing local
and global winds. Some winds or air currents are called prevailing winds
because they blow from one direction. The trade winds blow from
east to west and were the winds that blew the sailing ships from Europe
to the New World to explore, settle and trade. The prevailing westerlies
that blow from west to east are very strong winds that blow above 30 degrees
north and south latitudes.
Polar easterlies are weak winds but cause
many weather changes in the U.S. Jet streams are narrow belts of
fast moving air that move from west to east at high altitudes. They don't
stick to one path but move around disturbing air masses in the lower atmosphere
and affecting weather.
Tell the students that the study of weather and climate is called meteorology. Write this word on the board. Tell the students that it comes from a Greek word meteor which means something in the air. Write air, fire, water and land on the board. Tell them that one could say air, fire, water and land interact to make weather.
Tell the students that the Earth is surrounded by a blanket of air 434 miles thick called the atmosphere. Write atmosphere next to air. Energy from the sun passes through the Earth's atmosphere. One third of it bounces off, is reflected into space. The other two thirds is changed into heat. Write heat energy next to fire. The heat is held in by the Earth's atmosphere. This is called the greenhouse effect. Ask the students to imagine what it is like to sit in a closed-up car on a sunny day. Ask a student to describe it. Ask: Why do you think it gets so hot in a closed-up car? (Light passes through the windows, heats the inside of the car, but the heat cannot escape. The temperature inside the car rises.) Tell the children that a greenhouse for growing plants in cold weather works the same way. So does the Earth's atmosphere.
Show the students the transparency of the atmosphere and point out the four layers. Tell the students that weather happens in the troposphere, the layer closest to the ground, the layer full of water vapor and dust. Write vapor next to water on the board. Tell the children that if we had no atmosphere, the Earth would look like the moon. The moon doesn't have enough gravity to hold on to an atmosphere. Daytime temperatures on the moon could boil water if there was any water on the moon, but there's not. Nighttime temperatures drop to 200 degrees below zero and could freeze oceans if there were any oceans on the moon which there aren't. There are no trees, no oceans, no life on the moon. Thanks to Earth's gravity, we have an atmosphere thick enough to protect us from too much of the sun's rays and to hold in heat during the night to keep the planet from becoming a frozen icicle. What happens in our atmosphere, the way fire or heat energy, air, water and land interact causes weather. One could say that weather is what's happening in the atmosphere at a particular place at a particular time.
Show the students the globe and shine the flashlight directly on the equator as it spins. Tell the students that the sun's rays hit directly on the equator but the rays get spread out and don't heat up the poles as much. This uneven heating causes air to move. Ask: What do you think happens when air is heated? (Accept all answers.)
Show the students the empty soda bottle. Show them the container of water and specify
which is ice water and which is hot water. Place the soda bottle in the ice water. Ask: What do you think will happen to the air in the soda bottle? (It will get cold.) After a minute or two, put a
balloon over the neck of the bottle. Now place the bottle in the hot water. The balloon will begin to inflate. Ask: What do you think is happening to the air inside of the bottle? (It is being heated by the hot water around it.) Tell the students that when air is heated, it spreads out and gets thinner and lighter. It moves upward and fills the balloon. Ask: What do you think will happen when I put the bottle in the cold water again? (The balloon will deflate.) Put the bottle in the ice water. When the balloon deflates, ask: What do you think happened to the air that was in the balloon? (It was cooled.) Tell the students that cold air takes up less room than warm air and it is heavier. Cold air sinks. On the board draw an arrow going up and label it warm air and one going down and label it cool air. Point out to the students that when they open the refrigerator, cold air spills out on their feet. When they open the oven, hot air hits them in the face. Ask: What happens when air is heated? (It spreads out and rises.)
Ask: Do you think water acts like air when it is heated? Do you think hot water molecules spread out, get lighter and move upward? (Accept all answers.) Distribute materials to groups. Have them cover their desks with newspaper for easier cleanup. Tell the students that what they are going to make is a working thermometer. A thermometer measures temperature. If water is like air and rises when it is heated, the thermometer will work. Have the students pour the red dyed water into the soda bottle and insert the straw. Tell them to plug up the hole around the straw with the wad of clay so that no air can get in the bottle around it. Tape the index card to the back of the straw. Place the soda bottle in the container of hot water. Ask the students to watch the colored water carefully. When they report that the water is rising, ask: Does heated water spread out and move up the straw? (yes) Ask the students to mark a line on the index card showing how far up the colored water rose. Ask: What do you think will happen when you put the soda bottle in the ice water? (Accept all answers.) Have the students move the bottle to the cold water container and mark a line on the index card as a cold water reading. Ask: Why do you think the liquid goes up and down in the straw? (Warm water spreads out and takes up more space in the straw. Cold water [and air] contracts and takes up less space. Cold water is also heavier and sinks.) Collect thermometers and materials.
Show the students the globe again. Tell them that when the air around the equator is heated, it rises. The heated air is lighter. We say it has less air pressure or low pressure. Write this on the board next to the up arrow. The heated air moves up and toward the poles where it is cooled. Show them this on the globe. Cooler air from the poles sinks because it is denser and heavier. We say it has high pressure because it puts more weight on the Earth. Write high pressure on the board next to the down arrow. This cooler, heavier air moves toward the equator. There it is heated, spreads out and floats up. This circulating of the air causes winds. Tell the students that air from areas of high pressure pushes in under areas of low pressure causing wind.
With the globe, show the students that while the wind is moving up and down, the Earth is moving, too. The Earth rotates from west to east at speeds of a thousand miles an hour at the equator and much faster at the poles. This affects the way the winds curve. Winds in the Northern Hemisphere curve to the right. Winds in the Southern Hemisphere curve to the left. Ask the students to watch the mountains, oceans, deserts, prairies, canyons, and jungles pass by as you spin the globe. Tell them that the polar ice caps reflect 90% of the sun's energy. Tropical rainforests absorb large amounts of energy. Oceans capture and hold heat longer than land. This
uneven heating also causes air movement or winds.
Tell the students that some winds or air currents are called prevailing winds because they blow from one direction. Show the students the transparency of prevailing winds. Point to the trade winds and tell them that trade winds blow from east to west and were the winds that blew the sailing ships from Europe to the New World to explore, settle and trade. The prevailing westerlies that blow from west to east are very strong winds that blow above 30 degrees north and south latitudes, below the Tropic of Capricorn and above the Tropic of Cancer. Point to this on the transparency. Point out the polar easterlies and tell the students that these are weak winds but cause many weather changes in the U.S. Tell the students that jet streams are narrow belts of fast moving air that move from west to east at high altitudes. Sometimes they switch paths and affect our weather by moving air below them in the lower atmosphere.
Ask: What makes the prevailing winds and all winds blow? (Uneven heating. Air moves from high pressure areas [cool air] and pushes into low pressure areas [warm air].)
Have students watch the weather forecast part of the evening news and
write down any terms they are unfamiliar with. Compile a list and have
students take turns tracking down information on each term in Suggested
Books and reporting to the class.
Fourth Grade - Science - Lesson 3 - Meteorology
Review the water cycle: evaporation, condensation and precipitation.
Predict where air from certain climates would be placed on a scale of relative humidity.
Describe how clouds are formed.
Identify cloud formations by type and record cloud observations over
a week's time.
Transparency of water cycle (see attached)
Cloud Watchers Guide and Cloud Record sheets (see attached)
Allaby, Michael. How the Weather Works. Pleasantville, NY: Reader's Digest, 1995. Includes an extensive "Cloud Atlas" with great photos of clouds.
McKeever, Susan, ed. Science Encyclopedia. New York: Dorling Kindersley, 1993. The section on weather in this generously illustrated encyclopedia is 32 pages long and well-written. The pages on cloud classification are outstanding.
McMillan, Bruce. The Weather Sky. New York: Farrar Straus, 1991. This is a cloud record kept over a year's time with photographs of clouds, their names, heights from the Earth, humidity on the ground when observed and charts showing position of the cloud in relation to any warm or cold fronts.
Morgan, Sally. Weather. New York: Time Life, 1996. Has a good
color spread on cloud formation.
Remind the students that last time they saw how heated air spreads out and rises while cool air is heavier and sinks. Ask: What happens to air at the equator as the sun shines directly on it? (It is heated, spreads out and rises or floats up.) Ask: Does this heated air form a high pressure or a low pressure area? (low pressure area because the heated air puts less weight or pressure on the Earth) Ask: Does cool air around the North and South Poles form a high or low pressure area? (high pressure because cool air is heavier and puts more weight or pressure on the Earth) Ask: What happens to cool air around the North and South Poles? (It sinks and moves down toward the equator.) Ask: What does all this movement of air cause? (prevailing winds)
Remind the students that last time they learned about how fire--heat energy from the
sun--and air--the layers of atmosphere--interact to heat the Earth unevenly and cause air to move about the globe as winds. Tell them that today they will be studying how the atmosphere soaks up water and how it releases it. They will also learn the answer to the question: Where can I find some dinosaur breath?
Point out to the students that water comes in three forms. Ask: What are three forms of water? (solid-ice, liquid-water, and gas-water vapor) Point out on the globe that at the Earth's poles water is locked up, frozen as ice in the polar ice caps. In liquid form it covers nearly three-quarters of the Earth as oceans and seas. Water vapor is in the air all around us. Ask: How did the water vapor get into the air? (It evaporated.) Ask: What happens if you leave a pan of water out for a few days? (The water evaporates. It goes into the air.) Write the word evaporation on the
board. Ask the students to imagine how much water evaporates from the oceans every day. The answer is millions of tons of water daily leave the oceans and become part of the atmosphere. Tell the students that they are all contributing to the amount of water in the atmosphere at this very moment. Ask: How do you think you are doing that? (by breathing, by sweating if it is warm in the classroom) Tell the students that the water vapor from their moist lungs is evaporating into the air with each breath. Tell them that plants breathe, too, and moisture evaporates from the leaves of all the trees, and from every blade of grass. Spin the globe and ask the students to imagine all the water being evaporated at this moment from every puddle, every leaf, every animal's exhaled breath, every fountain, every gutter, every stream, every lake, every glass of lemonade, every wet sidewalk, every ocean, every farm field, every sink, every wetland, (at this point, put your finger in your mouth to wet it and hold it up) every wet finger in the world. Evaporation is happening all the time. How much water vapor is there in the atmosphere at any time? The answer is about 14 million tons of moisture.
Ask: What do we call moisture in the air when we want to measure it? (humidity) Ask: Have you heard people say, "It is so hot and humid today."? Tell the students that some places have more moisture in the air, are more humid than others. Draw a horizontal line on the board. Write dry air and 0% humidity on one end and very wet air and 100% humidity on the other. Tell the students that you have drawn a relative humidity scale from dry air with little moisture in it to very wet air where there is high humidity. Have a student come up and place where they think the air over a desert would be on the relative humidity scale (near the dry air end). Point out that deserts have a dry climate so one would expect the air over a desert to be dry. Have another student place where they think tropical rainforest belongs on the humidity scale. (very wet air) Point out that there is a lot of rainfall in a tropical rainforest and one would expect in that climate that the air would be very humid. Ask: Is it wet or dry day today? Is there high humidity or low humidity? Have another student place Baltimore today on the scale. Ask a student to place air over a warm ocean on the scale (on the wet air end of the scale). Tell the students that when air cannot hold any more moisture we say it is at 100% humidity.
Ask: Which do you think holds more moisture--warm air or cool air? (warm air) Ask the students if they have ever looked at a cold soda can on a hot day and seen beads of water form and run down the sides of it. Tell them the beads of water are called condensation, something they may have learned about in a second grade study of weather. The cold can cools the air around it. Since warm air holds more moisture than cool air, the cool air has to let go of its extra moisture. The moisture condenses on the can and runs down in droplets. Write condensation on the board below evaporation.
Remind the students that last time, when you talked about the troposphere, the bottom layer of the atmosphere where weather happens, you said it was full of water vapor and dust. Tell the students that this dust is very important to the making of clouds. Water vapor usually needs something to condense on, like the side of the can. In the air, it condenses on tiny particles of dust and soot.
Point to the Bahamas on the globe and ask the students to imagine they have made a trip to the Bahamas and are relaxing in a small boat that bobs gently up and down in the warm Caribbean Sea. The sun is hot and reflecting off the aqua-blue water. There is a little breeze, but the air is humid. Say: You lean back and because you are wearing specially-made sunglasses that let you see every microscopic drop and speck in the sky, you watch as a cloud forms above you. Moisture from the warm water around you has evaporated into the air. Now the air is full of
water vapor. The warm air rises and as the air moves higher and higher, it begins to cool off. As it cools, it needs to let go of some of the moisture. The water vapor condenses in tiny droplets around dust particles. In the highest, coldest part of the cloud, some of the droplets even freeze into ice crystals. The droplets and ice crystals reflect the light from the sun so they look white. And there it is...a white cloud over the Caribbean Sea.
The cloud floats over an island and joins other clouds. Inside the cloud you see the tiny droplets of water bumping and sticking together and getting to be bigger and bigger droplets of water. The tiny droplets have grown to a million times their original size. The cloud turns a darker color because now the light cannot shine through it. Before long, the droplets are so big that they begin to drop from the cloud. They fall on the island as rain. They slide down the island's mountain together and back into the warm sea. What you have been watching from your boat with your special glasses is something called the water cycle.
Show the children the transparency of the water cycle and review evaporation, condensation and point out that the falling rain is called precipitation. Show the students that the water on our planet is recycled through the water cycle again and again and has been recycling for billions of years, since there was first water on Earth. Tell them that when a dinosaur yawned or roared or just breathed, water vapor from its breath re-entered the water cycle. That same water vapor has been recycled billions of times. Tell them that perhaps they are breathing in recycled dinosaur breath right now!
Distribute the Cloud Watcher's Guide and Cloud Record sheets. Tell the
students that no two clouds are alike but there are cloud families. Clouds
that are formed when warm wet air is pushed up to a cooler place are piled-up
and puffy looking. These are in the cumulus family. Clouds that
are formed in a layer of cool air without having to move up and down are
stratus family. They look like spreading flat sheets or layers.
There are words added to a cloud's name that also describe its. Alto
means high above the ground. Fracto means broken into pieces by
the wind. Nimbus means rain cloud. Knowing what kinds of clouds
are in the sky can give one a good idea about what kind of weather is coming.
Go over the Cloud Watcher's Guide and remind the students that some of
the cloud names were learned in their Second Grade unit on weather. If
possible, try with the students to identify any clouds seen from the classroom
window or take them outside for a cloud identification session. Show the
students pictures of different types of clouds from Suggested Books (The
Weather Sky by Bruce McMillan has good photos) and ask them to identify
them. Ask them to observe the clouds they see in the sky every day for
a week and record their observations. Help the students fill in the first
Fourth Grade - Science - Lesson 4 - Meteorology
Interpret information on a weather map.
Describe what happens when air masses meet.
Describe what causes lightning and thunder.
Build a rain gauge, measure and graph simulated rainfall.
Transparency of air masses (see attached)
Weather page from The Sun (one for each student)
A large watering can full of water (the sprinkler type)
For each group of five students: a tin can (coffee can) or flat-bottomed
plastic cup, a plastic ruler, a funnel short enough to clear the bottom
of the can or cup
Kahl, Jonathan. Weather Watch: Forecasting the Weather. Minneapolis, Lerner, 1996.
Kahl, Jonathan. Storm Warning. Minneapolis: Lerner, 1993.
Kramer, Stephen. Lightning. Minneapolis: Carolrhoda, 1992. Includes wonderful photos of lightning, discusses different types of lightning and how they are formed and suggests tips to avoid danger from lightning.
Polacco, Patricia. Thunder Cake. New York: Philomel, 1990. A grandmother eases her grandchild's fears of an approaching storm's thunder and lightning by including her in preparations for a "thunder cake.'
Pearce, Q. L. Lightning and Other Wonders of the Sky. Morristown,
NJ: Silver Burdett, 1989. Explores lightning as well as dust storms, meteors,
acid rain and trade winds.
Anthes, Richard. Meteorology. Upper Saddle River, NJ: Prentice-Hall, 1992. (0-13-231044-9) An in-depth text with lots of graphs and diagrams. A great resource for anyone with specific weather questions not generally addressed in books for children.
Duckworth, Carolyn. "Lightning Chasers." Ranger Rick Magazine,
July, 1988. Contains lightning facts as well as safety tips.
When reproducing the newspaper weather map, use a light setting and
reduce size or use legal-sized paper.
Air masses form over land or over water. There are four major air masses that affect the weather of the U.S. Air masses formed over northern seas are called maritime polar air masses. They are cool and moist. Continental polar air masses formed over land are cold and dry. Continental tropical air masses formed over Mexico and the southwestern U.S. are hot and dry and affect U.S. weather only in the summer. Maritime tropical air masses formed over the Gulf of Mexico and the southern Pacific Ocean are warm and moist.
These air masses are moved around the Earth by winds. When air masses of different temperature and humidity meet, a boundary is formed between them called a front. As in a battle, the two air masses do not mix but push against each other. Along a front the weather is very changeable and usually stormy. A warm front forms when a warm air mass, usually with a lot of humid air behind it, catches up with a cold air mass and moves over it. Rain normally comes
with a warm front followed by hot, humid weather. A cold front forms when a cold air mass pushes underneath a warm air mass and forces it upward. The rapidly rising warm air mass cools quickly and forms clouds that drop lots of rain. Violent storms often accompany a cold front,
followed by fair cool weather.
When two different fronts meet, expect to see rainstorms or snowstorms. When a warm front moves in to meet a cold front, nimbostratus clouds form. There is heavy rainfall or snowfall. If wind speed and temperature of the cloud are right, a blizzard is the result. When a cold front moves in to meet a warm front, thunderheads (cumulonimbus) form. Because of the quick cooling of warm, wet air, ice crystals and water droplets form in the cloud. Strong air currents cause them to bump together and static electricity builds up. Electrons, negatively charged particles from the ice, get knocked off in all the commotion and collect at the bottom of the cloud. The top of the cloud becomes positively charged. Lightning flashes between the top and bottom of the cloud or from cloud to cloud or cloud to ground release the charge. The lightning heats the air around it hotter than the surface of the sun. The superheated air expands so rapidly it breaks the sound barrier and we hear a loud clap of thunder. Thunder and lightning happen at the same instant but because the speed of light is greater than the speed of sound, we see the lightning and the thunder sound is delayed. One can tell how many miles away a storm is by counting the number of seconds after a lightning flash before thunder is heard and dividing by five. When one feels a blast of cool air as a thunderstorm approaches, it is air brought down by the rain from the top of a thunderhead.
Remind the students that they learned about how uneven heating of the Earth causes wind. Air moves from areas of high pressure to areas of low pressure. Demonstrate this by blowing up a balloon. Ask: Which is the high pressure area--inside the balloon or outside the balloon? (inside. The pressure is pushing the sides of the balloon out so that it inflates.) Ask: What will happen when I let go of the balloon? (all the air will rush out) Let go of the balloon. Ask: Where did the air from the balloon, the high pressure area go? (It moved from the balloon to the low pressure area around it.) Remind them that huge masses of air, many miles wide, form over land and over water. Depending on whether they are cold or warm, wet or dry, these air masses create areas of high pressure or low pressure. The uneven pressure moves the air masses around the Earth and they change the weather. Remind the students about the story to explain thunder, that the angels were moving furniture in heaven. Air masses are constantly being moved around the planet by wind.
Show the students the North American air masses transparency. Tell them that these are the air masses that affect the weather in the U.S. Ask: Where do cold, dry air masses come from? (north of the U.S. in Canada) Ask: Where do warm, moist air masses come from? (from the south, from tropical oceans) Ask: Where do cold, moist air masses come from? (from northern oceans)
Tell the students that when these air masses meet, they do not mix. They have a pushing war. They push against each other all along the boundary where they meet. This boundary is called a front. Write this word on the board. Tell the students that a weather front is just like a battle front with two armies trying to take over territory from each other. Along a front expect the weather to be changeable and often stormy.
Distribute the weather maps and tell the students that weather maps can give lots of
information about what's happening in the atmosphere at a particular time. Ask the students to see if they can locate on the map L or H. Ask: What do you think these letters stand for? (Low or high pressure area) Ask the students to see if they can locate on the map a symbol that looks like
this (Draw it on the board.)
Tell the students that this symbol shows a warm front (write
this on the board). This is the battle line that forms when a warm air
mass, usually with a lot of humid air behind it, catches up with a cold
air mass and moves over it. The warm front moves across the land and beneath
it there is usually rain. After the warm front passes over, expect hot,
humid weather. In what part of the country is the warm front now? Ask:
Do you think they are having sunny weather or rainy weather? (rainy) Write
rain then hot, humid weather next to warm front. Ask the
students to locate a symbol that looks like this on the map: (Draw it on
Tell the students that this symbol shows a cold front. (Write this on the board.) A cold front forms when a cold air mass pushes underneath a warm air mass. Because the cold air has more pressure, it works like a wedge and forces the warm air on top of it upward. That warm air rises so quickly and cools off so fast that big clouds form and drop lots of rain. Windy storms often come with a cold front, followed by fair cool weather. Ask: What part of the country do you think they might be having storms? (where there is a cold front) Write rain and wind then cool and fair next to cold front.
Tell the students that when a cold front and a warm front collide, there will be heavy rainfall or snowfall. In the winter, if the winds are strong and the temperature up in the clouds is low enough, it makes a blizzard. We get snowed in and plows have to shovel out the roads. In the summertime when a cold front and warm front collide, thunderheads form. Show a picture of thunderheads (cumulonimbus) from Suggested Books. Tell the children that with thunderheads come thunderstorms. Ask students to look at the precipitation key on the weather map and find the sign for thunderstorms. Ask them to see if there are any thunderstorms predicted for the U.S. Where?
Ask the students to describe a thunderstorm. Write on the board the descriptive words they use. If they have trouble, suggest they finish these sentences: The thunderclouds were the color of______. The thunder sounded like_____. The wind sounded like_______. The rain felt like_______. The lightning looked like_____. After the storm, the air smelled like_____.
Remind the students that when warm, moist air is forced upward higher and higher, it is quick-cooled and ice crystals form high in the clouds. Lightning happens when strong air currents moving up and down inside the clouds cause ice crystals to move up and down and bump against each other. They make something called static electricity. Ask: Have you ever scuffed your feet on a rug, touched a doorknob and felt a little electric shock? Tell the students that when they rubbed their feet on the rug, they were building up an electrical charge. When they touched the door knob, they were releasing the charge. Lightning is the release of the electrical charge built up by all those rubbing ice crystals inside the thunderheads. It flashes between the top and bottom of a cloud or from cloud to cloud or from a cloud to the ground and releases the charge. Tell the students thunder happens when lightning flashes. The lightning heats the air around it five times hotter than the surface of the sun. Ask: What does heated air do? (It spreads out. It expands.) The superheated air around lightning spreads out so fast, it makes a loud noise, a
clap of thunder. Tell the students that you are going to ask them a trick question. Ask: Which comes first: lightning or thunder? Tell the students that the answer is they both happen at exactly the same moment. The reason we hear thunder after we see the lighting is that light from the flash reaches our eyes before the sound waves can reach our ears. We see the lightning but the
thunder sound is delayed. Tell the students that one way to tell how many miles away the lightning is striking is to count the number of seconds--one chimpanzee, two chimpanzee-- after a lightning flash until thunder is heard, then divide the number of seconds by five. That will be
the number of miles away lightning is striking.
Ask the students to look again at the national weather map. Tell the students that there is a lot of information besides fronts and precipitation on the weather maps. Point out again the precipitation key for finding out where there is rain or thunderstorms. Point out, also, the key for temperatures. Tell the students that there is also information about the hottest and coldest places in the country and what year Baltimore had the highest temperature on this date. Divide the class into two teams for a game of Weather Info. Tell the contestants that the answers to all weather questions in Weather Info can be found on the weather map. Write team names (example: Lightning and Thunder teams) on the board and keep score during the game--one point for each correctly answered question. Following are a list of sample questions:
1. Looking at the Maryland weather map, what are the predicted high and low temperatures in Cumberland, Maryland?
2. What is the predicted high temperature for Ocean City today?
3. From which direction are the winds blowing on the Chesapeake Bay?
4. What time does the sun rise today?
5. What are the high and low temperatures for the nation's capital today?
6. Looking at the national weather map, what is the temperature in Dallas, Texas?
7. Is any rain expected in Dallas today?
8. On what date is the next full moon?
9. What was the high temperature for Hong Kong, China yesterday?
10. How much precipitation did Baltimore get yesterday?
11. What was the relative humidity at 8AM yesterday?
12. How big will the waves be on the Chesapeake Bay today?
13. In the city records, what is the highest recorded temperature for this date?
14. What was the year that highest temperature was recorded?
15. What was the pollen count for the Baltimore area: high or low?
16. What is the normal temperature recorded for B.W.I. (Baltimore Washington Airport) on this date?
17. What times are the high tides in Ocean City today?
Tally the scores and declare a winning team for the Weather Info game.
Ask: If you wanted to measure how much rain fell in a day at a certain place, how would you do it? (Accept all answers.) Tell the students that there is an instrument called a rain gauge that is used to measure precipitation. It is a very, very simple device. Tell the students that they will be given the materials to make one and you are sure they will be able to figure out how to build a rain gauge. When the students have completed their rain gauges, tell them you will make it rain in the classroom so they can test them out. Divide the class into groups of five and distribute supplies. As the devices are completed (this should take very little time) go to each group with the watering can and make it rain for eight seconds. Be sure the students time the
rainfall (one chimpanzee...two chimpanzee, etc.) If possible, make it rain "harder" for some groups. Have the groups measure precipitation. Make a bar graph (amount of rainfall in eight seconds/ Group A, Group B, etc.) on the board and have a member of each group come up and
record their groups' results. Ask: Were there big differences in amounts of rainfall around the room?
Write about a thunderstorm you have experienced. Be sure to describe
it using all your senses: how it sounded, looked, felt, smelled, even how
the air tasted. Did the storm frighten you? Was it exciting?
Fourth Grade - Science - Lesson 5 - Meteorology
Vortex project adapted from Science Projects About Weather by
Robert Gardner and David Webster
Describe how hurricanes and tornadoes form.
Create a vortex.
Map of the U.S.
Radar pictures and diagrams of a hurricane from Suggested Books
Pictures of hurricane damage from Suggested Books
Pictures of tornadoes from Suggested Books
For each group of five students: two 1/2-liter or 1-liter plastic soda
bottles (one 3/4 filled with water with a few drops of food coloring in
it), masking tape or duct tape
Cole, Joanna. The Magic School Bus Inside A Hurricane. New York: Scholastic, 1995.
Gardner, Robert and David Webster. Science Projects About Weather. Springfield, NJ: Enslow, 1994."Explore-on-your-own" projects are simple and accompanying text is directly applied.
Kahl, Jonathan. Weather Watch: Forecasting the Weather. Minneapolis, Lerner, 1996.
Lauber, Patricia. Hurricanes: Earth's Mightiest Storms. New York: Scholastic, 1996. A beautifully-written description of the life and destruction caused by a hurricane in 1938. Includes information on hurricane formation as well as forecasting and tracking techniques.
Lee, Sally. Hurricanes. New York: Franklin Watts, 1993.
Ramsey, Dan. Weather Forecasting: A Young Meteorologist's Guide. New York: TAB Books, 1990.
Souza, D.M. Hurricanes. Minneapolis: Carolrhoda, 1996. Good information
and dramatic satellite pictures of hurricanes and their effects.
The word hurricane comes from a Carib Indian word that means big wind. On the other side of the world hurricanes are called typhoons. In the Indian Ocean they are called cyclones. Hurricanes begin as tropical storms over warm tropical oceans. Warm, moist air above the ocean rises and more moist air rushes into the low pressure area. That warm air rises, cools, condenses and forms clouds. More warm, moist air from below rushes in and the blowing wind begins to spiral because of the rotation of the Earth forming a chimney with warm air rising on the outside, condensing at the top and falling in the middle. The winds pick up speed and the clouds are blown around and around the spiral. Unlike a thunderstorm over land, a hurricane has the whole ocean from which to suck moisture. If a tropical storm doesn't die out after a few hours, and most do, it can grow to be hundreds of miles across with wind speeds of 74 mph. Then it is a hurricane. At the center of the hurricane, the eye of the storm, there is an area of very low pressure where the winds are calm. Hurricanes travel slowly at first, only ten to twenty miles per hour but pick up speed and can cover up to 60 miles an hour. Hurricane high winds and torrential rains can cause a lot of damage when they strike land. Hurricanes also cause storm surges, huge waves that flood coastal areas. Once over land, however, hurricanes run out of the water supply they need to keep the hurricane engine going and they die out.
Tornadoes resemble hurricanes in their formation but they don't form over water. They are whirling winds that blow around an extremely low pressure area. They form a funnel shape with wind speeds exceeding 300 mph. Tornadoes are small storms (funnels are usually only 200-300 yards wide) but their high winds can cause extensive damage. The U.S. has more tornadoes per year than any other country; approximately 700 tornadoes are reported annually, most of them in Tornado Alley, an area of the central plains that includes Oklahoma, Texas and Kansas. Tornadoes form when a wedge of cold air forces warm, humid air quickly up and more warm, moist air is drawn up to replace it. The funnel cloud descends from a severe thunderstorm and sucks up soil, cars, trucks, animals, people, buildings and anything else in its path, spiraling it up at greater and greater speeds.
Remind the students that last time they learned when a cold front and warm front collide, thunderstorms can form. Tell them that today they are going to learn about the most dangerous thunderstorms in the world--the ones that grow into hurricanes and tornadoes. Write the word hurricane on the board and tell the students that when Columbus first landed in the New World, he heard the Caribbean Indians talk about hurikan, a big wind. It wasn't long before Columbus experienced the "big wind" himself when the island was hit by a hurricane. Tell the students that in Asia, hurricanes are called typhoons. In the Indian Ocean, they are called cyclones. Write typhoons and cyclones on the board.
Ask: Does anyone remember hearing about a hurricane that hit Maryland? (Accept all answers.) Tell the students that hurricanes are given names. For instance, the hurricane that hit Maryland in 1972 was named Agnes. Agnes did more damage with its high winds and heavy rains than any other hurricane in history until 1992 when Hurricane Andrew struck the Florida Everglades. Tell them that hurricanes named Hazel and David also hit Maryland. Ask: Why do you think they give hurricanes names? (It is easier to keep track of them if they have names.) Tell the students that every six years a list of names is drawn up, one name for each letter of the alphabet. The World Meteorological Association uses this list to name hurricanes beginning with an A name such as Andrew or Agnes and continuing through the alphabet as each storm develops. Ask: Where do you think hurricanes come from? (Accept all answers.) Show the students on the globe the equatorial waters off the coast of Africa. Tell the students that most hurricanes that threaten the U.S. form out here.
Tell the students that hurricanes begin as tropical storms over warm tropical oceans. Show the students radar pictures and diagrams of hurricane formation from Suggested Books. Tell them that meteorologists, people who study weather patterns and forecast the weather, know that hurricanes form when there is a low pressure area. The warm, moist air above the ocean rises and more moist air rushes in to replace it. That warm air rises, cools, condenses and forms clouds. More warm, moist air from below rushes in and the blowing wind begins to spiral because of the rotation of the Earth. It forms a chimney with warm air rising on the outside, condensing at the top and falling in the middle. The winds pick up speed and the clouds are blown around and around the spiral. This whirling spiral is called a vortex. (Write this on the board.) At the center of the spiral is the eye of the storm. In this eye, the air pressure is very low and the winds are calm. The hurricane pulls more and more moisture from the ocean to fuel itself. Most of these tropical storms die out after a few hours, but some continue to grow. They can get to be hundreds of miles across with winds blowing 74 miles per hour. When the winds get that fast, the storm graduates from being a tropical storm and becomes a hurricane.
Ask: On a day when the wind is blowing gently, how fast do you think it is blowing? (4 mph) How fast do you think the wind is blowing on a day when it can yank an umbrella out of your hand? (25 mph) How fast do you think the wind is blowing when trees get knocked down? (55 mph) How fast is the wind that can upturn cars? (65 mph) Remind the students that hurricane winds blow at 74 mph and faster.
Tell the students that they are going to create a vortex. Ask: What is a vortex? (a whirling spiral) Divide the class into groups of five and distribute the materials to build a vortex. Have the students tape the mouths of the bottles together with a long strip of masking or duck tape so no water will leak out. Have them flip the bottles (like turning over an egg timer) so the full bottle is on top. Swirl the bottles around for a few seconds and put them on the table. Ask: Have you created a vortex? What is happening in the center of the vortex? (air, no water) Tell the students that this is like the calm eye of the hurricane with swirling winds all around it. Ask: Which way is the water moving, clockwise or counterclockwise? Students can repeat the vortex creation so everyone has a chance to make one. Ask: Can you reverse the vortex and make it spin in the other direction?
Tell the students that if hurricanes stayed where they formed and didn't travel, they wouldn't be so dangerous. Ships and planes could avoid them. But hurricanes do travel. They travel slowly at first, only ten to twenty miles per hour, an easy pedaling speed on a bicycle. But then they start to move faster and travel at 60 mph--highway speed. They can change direction at any time and veer north or west. Hurricanes can move in unpredictable ways.
Ask: Suppose one day you heard on the news that a hurricane was coming
up the coast and might strike the Chesapeake Bay area. What kind of weather
would you expect? (very high winds and very heavy rains) Tell the students
that hurricane winds can cause a lot of damage. Heavy rains can cause flooding.
Hurricanes also cause storm surges which are huge waves that flood coastal
areas. If available, show the students pictures of hurricane damage from
Suggested Books. Tell the students that in the past, meteorologists, did
not have enough information to warn people that a hurricane was coming.
Many people lost their lives. Today when meteorologists suspect a hurricane
is forming, they watch it closely to see if it might move toward land.
If they think a hurricane may strike an area, they issue a hurricane
watch for that area. If they think it is likely that the hurricane
will strike in the next 24 hours, a hurricane warning is issued.
Ask: How do you think people can prepare for a hurricane? (boarding up
windows so broken glass won't fly; sandbagging to keep rising water from
flooding homes; evacuating and moving away from the area until the hurricane
has passed) Share some other preparation tips with the students, such as
filling jugs with clean water in case drinking water is contaminated. In
case there is a power outage, have flashlight with fresh batteries and
a portable radio to listen to weather bulletins and emergency information.
Do not go outside during a hurricane. If it seems like the winds have stopped,
it may be just the calm eye of the hurricane passing over. The violent
winds will begin again, blowing in the other direction, very soon. Tell
the students that when hurricanes move inland, they die out quickly. That
is because they run out of the water supply they need to keep the hurricane
engine going. Without water, they die out.
Tell the students that the vortexes they created are also called "tornadoes-in-a-bottle." Ask the students if they have seen pictures of tornadoes on T.V. Ask a volunteer to come up and draw on the board the shape of a tornado. Tell the students that the U.S. has more tornadoes per year than any other country--700 tornadoes a year. Tell the students that most of the tornadoes occur on the central plains in these states: Oklahoma, Texas and Kansas. Have a student come up and point these states out on the map. Tell the students that this area of the country is sometimes called Tornado Alley. Show students pictures of tornadoes from Suggested Books. Point out that the whirling clouds resemble the vortex of hurricanes but tornadoes form over land, not water. Tornadoes form when warm, moist air from the south meets cool, dry air moving from the Rocky Mountains. Indicate this on the map. Tell the students that warm, humid air is forced to rise quickly and thunderstorms result. Inside the thunderclouds, winds begin to whirl at speeds of over 300 mph. A funnel cloud of whirling winds descends from the thunderstorm and sucks up soil, cars, trucks, animals, people, buildings and anything else in its path, spiraling them up at greater and greater speeds. Inside the vortex, like the vortex you created, there is an area of very low pressure. Tornadoes last only a half-hour or so. As winds die, objects and debris that the storm picked up are dropped.
Have groups do research projects on famous hurricanes such as Andrew,
Gloria, Hugo, Agnes, Hazel and Camille. Find out information about where
and when the hurricane hit, whether hurricanes had hit there before, the
storm's fastest wind speed, what kind of damage it did.
Fourth Grade - Science - Lesson 6 - Meteorology
Hygrometer building activity from Science for Kids by Robert
Describe some measuring devices used at weather stations.
Build a simple humidity indicator or hygrometer.
Describe some tools used in weather forecasting.
Use a homemade "weather" balloon to measure and compare classroom temperatures
near the floor and at the ceiling.
Pictures of a barometer, weather vane and anemometer from Suggested Books
1-liter soda bottle with top cut off, spray bottle full of water
One or two helium balloons, string, a lightweight (working) keychain thermometer
For each group of four or five students: a pencil, a piece of
aluminum foil 4" wide and 10" long, a piece of newspaper 1" wide and 10"
long, scotch tape, scissors, a spool from sewing thread
Allaby, Michael. How the Weather Works. Pleasantville, NY: Readers Digest, 1995.
Cosgrove, Brian. Weather. New York: Knopf, 1991. This Eyewitness book has good photos of weather instruments on pages 42-43.
Gibbons, Gail. Weather Forecasting. New York: Four Winds, 1987. Simple text and illustrations show what meteorologists and weather forecasters do. Also has illustrations of equipment in a weather station.
Ganeri, Anita. Weather. New York: Franklin Watts, 1993.Contains some pictures of weather equipment plus stories of wild weather occurrences (raining fish?)
Kahl, Jonathan. Weatherwatch: Forecasting the Weather. Minneapolis: Lerner, 1996. Good picture of a weather balloon ready to be launched.
Kahl, Jonathan. Weatherwise. Minneapolis: Lerner, 1992. Short chapter on weather forecasting showing a radar picture.
Lauber, Patricia. Hurricanes: Earth's Mightiest Storms. New York: Scholastic, 1996. Includes multiple satellite pictures of Hurricane Hugo and pictures of weather instruments on
Simon Seymour. Weather. New York: Morrow, 1993. Includes the ultimate photo of a weather balloon and also a short discussion of global warming.
Wyatt, Valerie. Weatherwatch. New York: Addison Wesley, 1990.
Suggests how to set up a class weather station and weather record keeping
Wood, Robert. Science for Kids: 39 Easy Meteorological Experiments.
Blue Ridge Summit, PA: TAB, 1991.
It is vital that people have early warning of the possibility of tornadoes and hurricanes in order to make preparations and/or evacuate a dangerous area. Doppler radar is a particularly useful tool in tracking thunderstorms and predicting tornado formation. Radar equipment sends out radio waves which bounce off rain and snow inside clouds. The echoes that return let meteorologists make a picture of the insides of clouds and measure how fast they are moving.
Meteorologists look for a hook-shaped area in a thunderstorm on the radar picture as a sign a tornado might be forming.
Over 600 weather stations nationwide take ground-level measurements of air pressure, temperature, relative humidity, wind speed, wind direction, clouds, precipitation and visibility every one to three hours. The recorded data is collected by the National Weather Service in Asheville, North Carolina which issues round-the-clock information to meteorologists at radio and T.V. stations, newspapers and to airports and the military. The tools meteorologists use in the weather stations are anemometers to measure wind speed and direction, barometers to measure air pressure, thermometers to measure temperature, rain gauges to measure rainfall, and hygrometers to measure relative humidity. Weather satellites (Skylab), weather balloons and weather buoys anchored out at sea also record data that is collected by the National Weather Service. Weather satellites carry cameras and computers and send back pictures of the atmosphere and weather patterns over the oceans. Weather balloons carry radiosondes, instruments that send back information through radio transmissions from high in the atmosphere.
To forecast the weather, meteorologists study computer-generated weather
maps, satellite photos, and radar pictures. They use their knowledge of
weather patterns, just as the farmers and sailors did in the past, to predict
what the weather will be. They are sometimes wrong in their weather forecasts
because the information they have is never totally complete. Conditions
everywhere in the world cannot be monitored at every second. With gaps
in information, forecasts cannot be totally accurate.
Ask: What are the two most dangerous storms? (hurricanes and tornadoes) Ask: How do we know if a hurricane or tornado is going to be a threat to our area? (Meteorologists issue a hurricane watch or a tornado watch or warning.) Ask: What kind of information do you think meteorologists and weather forecasters collect that help them predict weather changes in Baltimore? Make a list on the board. Some things on the list might be: temperature, types of clouds, air pressure, humidity, how fast the wind is blowing and in which direction it is coming from. Tell the children that to get the information they need, meteorologists depend on some basic measuring equipment, on radar and computers, and on the National Weather Service.
Tell the students that first you'd like to talk about some of the basic measuring equipment every weather station has. Ask: What instrument would you use to measure temperature? (thermometer) Ask: What instrument would you use to measure changes in air pressure? (barometer) Show the students a barometer or a picture of a barometer from Suggested Books. Ask: If the air pressure is steady or rising, what kind of weather might we expect? (fair weather) If barometric pressure is falling, what kind of weather would we expect? (possibly stormy) Show the students a picture of a weather vane. Ask: What information can we get from a weather vane? (wind direction) Tell the students that if there is a change in the wind's speed or direction, it can mean a front is moving through. Point out the stationary indicators of the cardinal directions and how the wind catches the broad side of the weather vane and pushes it around until the pointer is facing into the wind. Show the students pictures of an anemometer. Ask: What do you think this instrument can measure? (wind speed) Point out the cups that catch the wind and spin
and the indicator that tells how fast they are going. Tell them that meteorologists use an instrument called a hygrometer to measure humidity. Remind the students that they placed deserts and tropical rainforests on a scale of relative humidity from 0% to 100%. Tell them that today they will build very simple hygrometers.
Divide the class into groups of four or five and distribute materials. Demonstrate how to make the hygrometer: Place the newspaper strip in the middle of the aluminum foil strip and tape just the edges down. Trim the edges of the foil with scissors so that the foil strip is about 1 " wide with the newspaper strip running down the middle. Tape one end of the strip to the pencil and wind the strip around the pencil so the newspaper is inside and the aluminum foil is showing. Stick the point of the pencil into the hole in the thread spool so it will stand up. Have the groups make the hygrometers. Spray a light mist of water inside the soda bottle. Ask: Is the air humid inside the soda bottle? (yes) Ask one of the groups to bring up their hygrometer and see if it can indicate the change in humidity of the air inside the soda bottle. Place the hygrometer on the table and place the soda bottle over it. The strip of foil will begin to unwind. Ask: How does the hygrometer show the change in humidity? (unwinds) Remove the soda bottle. The foil will wind back up. Ask: How do you think it works? (The paper absorbs moisture and expands-unwinding happens. As it dries in drier air, the paper shrinks again and the coil winds up again.) Students can take the hygrometers home to test the humidity in different rooms, especially the bathroom.
Tell the students that meteorologists also use radar to see what is happening inside clouds. Radar equipment sends out radio waves. The radio waves bounce off rain and ice crystals inside clouds. The echoes that return let meteorologists make a picture of the insides of clouds and measure how fast they are moving. If they spot a hook-shaped area in a thunderstorm on the radar picture, it is a sign a tornado might be forming. Ask if students have seen radar pictures on the evening weather reports on T.V.
Tell the students that weather satellites carry cameras and computers and send back pictures of the atmosphere and weather patterns over the oceans. It is especially important to keep an eye on hurricanes developing. Weather balloons carry instruments that send back information from high in the atmosphere.
Tell the students that this is how the National Weather Service works: There are over 600 weather stations all over the country. At each weather station meteorologists take measurements of air pressure, temperature, relative humidity, wind speed, wind direction, clouds, precipitation and visibility every one to three hours. That recorded information is collected by the National Weather Service in Asheville, North Carolina. They issue round-the-clock information to meteorologists at radio and T.V. stations, newspapers and to airports and the military.
To forecast the weather, meteorologists study computer-made weather maps, satellite photos, and radar pictures. They use their knowledge of weather patterns to predict what the weather will be. Ask: Is the weather report always right? (no) Why do you think it is sometimes wrong? (The information the meteorologists have isn't complete. Conditions change every second.)
Tell the students you would like to try out a weather balloon. Ask: How can I find out what the temperature is like near the ceiling? (Tie a thermometer to the balloon and send it to the ceiling.) Have some volunteers come forward. Have one of them read the temperature at desk level and record it on the board. Have another volunteer help secure the instrument (thermometer) to the weather balloon(s). Carefully and slowly, allow the weather balloon to ascend to ceiling level. Ask: Do you think it will be warmer, colder or the same temperature at
the ceiling? Why? After a few minutes, retrieve the weather balloon
and have a volunteer read the temperature and record it on the board. Discuss
the results. If the ceiling temperature was warmer, ask the students why
they think the temperature is higher there. Remind them that warm air rises
and cool air sinks.
Fourth Grade - Science - Lesson 6 - Meteorology
Possible Field Trip
Visit a weather station or a meteorologist at a TV station.
Adapted from How the Weather Works by Michael Allaby, page 162.
Identify some ways humans affect the weather.
Demonstrate what affect global warming will have on sea level.
For each group of five students: aluminum tray or baking dish, modeling
clay, a container of water, ice cubes, grease pencil
Tell the students that meteorologists at the National Hurricane Center have reported that the number of hurricanes is increasing. They believe it might have something to do with global warming. Because we have records of temperatures over many years in places all over the world, scientists have noticed that gradually, the Earth's atmosphere is getting warmer. Humans have added pollutants to the atmosphere that have increased the greenhouse affect. Pollution from the exhaust of cars and buses and burning coal to make electricity have added gases to the atmosphere that hold in more heat. One worry about global warming is that the higher temperatures might cause the polar ice caps to melt. Ask: What do you think would happen if the ice caps, where so much of the Earth's water is frozen, were to melt? (Accept all answers.) What would happen to islands or coastal cities such as Baltimore or New York?
Distribute materials to groups and ask them to make clay islands and a continent on the edge of their trays. Put ice cubes (polar ice caps) on the continent. Fill the rest of the tray with "ocean" and mark the sea level with the grease pencil. Allow the ice caps to melt. Ask: What affect did the melting ice caps have on the islands and continent? Did sea level rise? Are the coastal cities underwater? Ask the students to write a paragraph about what action they think people should take to keep this disaster from happening.
*Bryan, Ashley. The Story of Lightning and Thunder. New York: Atheneum, 1993. (0-68931-836-7)
Davis, Hubert. A January Fog Will Freeze a Hog and Other Weather Folktales. New York: Crown, 1977. (0-51752-811-8)
Lauber, Patricia. Hurricanes: Earth's Mightiest Storms. New York: Scholastic, 1996. (0-590-47406-5)
Mayo, Gretchen. Earthmakers' Tales: North American Indian Stories about Earth Happenings. New York: Walker, 1989. (0-80276-840-7)
McVey, Vicki. The Sierra Club Book of Weatherwisdom. Boston: Little Brown, 1991. (0-31656-341-2)
Milord, Susan. Tales of the Shimmering Sky. Charlotte, VT: Williamson, 1996. (1-88559-301-5)
Polacco, Patricia. Thunder Cake. New York: Philomel, 1990. (O-590-45426-9)
Allaby, Michael. How the Weather Works. Pleasantville, NY: Readers Digest, 1995. (0-89577-612-X)
Ardley, Neil. Science Book of Weather. San Diego: Harcourt, 1992. (0-15200-6249)
Bower, Miranda. Experiment with Weather. Minneapolis: Lerner, 1994. (0-82252-458-9)
Branley, Franklyn. It's Raining Cats and Dogs: All Kinds of Weather and Why We Have It. Boston, Houghton, 1987. (0-395-33070-X)
Cole, Joanna. The Magic School Bus Inside A Hurricane. New York: Scholastic, 1995. (0-590-44686-X)
*Cosgrove, Brian. Weather. New York: Knopf, 1991. (0-679-90784-X)
Flint, David C. Weather and Climate. New York: Gloucester, 1991. (0-53117-321-6)
Ganeri, Anita. Weather. New York: Franklin Watts, 1993. (0-531-14250-7)
Gardner, Robert and David Webster. Science Projects About Weather. Springfield, NJ: Enslow, 1994. (0-89490-533-3)
Gibbons, Gail. Weather Forecasting. New York: Four Winds, 1987. (0-02737250-2) Hiscock, Bruce. The Big Storm. New York: Atheneum, 1993. (0-68931-770-0)
Kahl, Jonathan. Weather Watch: Forecasting the Weather. Minneapolis, Lerner, 1996. (0-8225-2529-1)
________, Jonathan. Weatherwise: Learning About Weather. Minneapolis, Lerner, 1992. (0-82252-525-9)
________, Jonathan. Storm Warning. Minneapolis: Lerner, 1993. (0-82252-527-5)
Kramer, Stephen. Lightning. Minneapolis,: Carolrhoda, 1992. (0-87614-659-0)
Lambert, David. The Weather and Its Work. New York: Facts on File, 1987. (0-87196-987-4)
Lee, Sally. Hurricanes. New York: Franklin Watts, 1993. (0-53120-152-X)
McKeever, Susan (ed). Science Encyclopedia. New York: Dorling Kindersley, 1993. (1-56458-328-7)
McMillan, Bruce. The Weather Sky. New York: Farrar Straus, 1991. (0-374-38261-1)
Morgan, Sally. Weather. New York: Time Life, 1996. (0-8094-9370-5)
Pearce, Q. L. Lightning and Other Wonders of the Sky. Morristown, NJ: Silver Burdett, 1989. (0-67168-648-8)
Ramsey, Dan. Weather Forecasting: A Young Meteorologist's Guide. New York: TAB Books, 1990. (0-83063-338-3)
Simon Seymour. Weather. New York: Morrow, 1993. (O-688-10547-5)
Souza, D.M. Hurricanes. Minneapolis: Carolrhoda, 1996. (0-87614-861-5)
Suzuki, David. Looking At Weather. New York: Wiley, 1991. (0-47154-047-1)
Watson, Benjamin. The Old Farmer's Almanac of Weather and Natural Disasters. New York: Random House, 1995. (0-67975-788-0)
Wolff, Barbara. Evening Gray, Morning Red: A Ready-to-Use Handbook of American Weather Wisdom. New York: Macmillan, 1976. (0-02993-320-2)
Wyatt, Valerie. Weatherwatch. New York: Addison Wesley, 1990.
*Required or strongly recommended for lessons