Printer Friendly



A cloud is just a visible collection of water droplets, ice crystals, or a mixture of both that is suspended in the air. You can look up and see clouds on most days in most places, even in dry regions (like Arizona and coastal southern California). There can also be clouds of dust, smoke, and volcanic ash. In fact, last month, the small eruptions from Mt. St. Helens created an ash cloud that, when viewed from a distance, looked much like a towering cumulus cloud. Other examples of clouds include tornadoes, waterspouts and dust devils. Astronomers may study clouds or nebula in space or clouds on planets.

On October 4, 2004, the United States Postal Service recognized clouds by issuing a 15-stamp sheet called "Cloudscapes." You can learn more about these stamps by visiting the National Weather Service--Memphis web site (see the Science Weekly web site for links and images (1)).

Cloud Types

Meteorologists classify clouds into three basic types because of the pioneering work of Luke Howard, a British chemist, in 1803. Howard used Latin root words to name the clouds based on their characteristics or shapes.

The three basic cloud types, from lowest to highest altitude, are: stratus, cumulus and cirrus (see "Cloud Type Table" on our links page (1)).

Howard then used prefixes and suffixes to further define the many other cloud types that he observed. Alto- means high, cirro- are wispy, ice crystal clouds, and -nimbus means rain. Thus, altocumulus is a puffy cloud at high altitude and cumulonimbus is a cumulus cloud that rains. All in all, there are 10 distinct cloud types (see links page (1)).

Cloud Formation

Clouds form under many conditions. The most common is when moist air rises because winds blow up and over mountains, the sun heats air near the ground, or weather fronts push air upward. Cumulus-type clouds (and the tallest cumulus cloud, the cumulonimbus or THUNDERSTORM) are often the result. The most intense thunderstorms (and their dangerous offspring--tornadoes, high winds, hail and torrential or flooding rains)--often occur with cold fronts. Cold fronts are regions where cold air often pushes warm air forcibly out of the way both horizontally and vertically. Steadier rain and snow occur near warm fronts (where warm air pushes cold air away more gently), although thunderstorms can occur with these fronts, too.

Thunderstorms over the Florida peninsula occur almost like clockwork, especially during summer afternoons. Daytime heating of the land, enhanced by miniature cold fronts known as sea breeze fronts (cooler ocean air tries to displace the warmer air over Florida), forces warm and very humid air high into the atmosphere.

Mountain areas are another favored place for thunderstorms. Air flowing upward, coupled with the heating of the ground, can lead to some very strong thunderstorms. The Colorado Rockies are known for these storms.

Areas along the east and south shores of the Great Lakes may receive heavy snow in winter as cold Canadian air blows across the warmer lakes. Much like the air over ground is warmed due to sunlight heating the ground, the warm lake waters heat the cold air. Then clouds form and eventually heavy "lake effect" snow falls. The same effect has been observed along the south and east shores of the Great Salt Lake in Utah.

All of these situations involve relatively moist air that rises either gradually or quickly. Rising air cools because it uses up energy; the cooling process allows condensation to occur and clouds to form.

On the other hand, clouds can form whenever air cools. Sometimes, especially at night, air near or over cold water, cold ground, or snow cover may be cooled through contact. This chilling effect can also lead to condensation and the formation of low, layered clouds--stratus or fog. The California and New England coasts are well known for the frequent occurrence of stratus clouds.

Warm fronts, especially in winter, involve warm air moving across cold ground or water surfaces. This typically leads to situations involving very dense fog. In some places, this type of fog is known as "pea soup" fog because it is so thick, much like split pea soup.

We have all seen condensation in our lives. Cumulus-type clouds often rise above a pot of boiling water or from a factory smoke stack. The lava lamp provides a highly visual perspective of a fluid heated from the bottom. Stratus-type clouds are best seen when shallow ground fog lies along the ground but the sky is clear above. Condensation shows itself as dew on grass or on our cars; moisture on the outside of a glass of water or soda on a summer day; or "fog" that forms on our bathroom mirror as we take a shower. If it is very cold outside, condensation can sometimes form on the inside surface of windows of our home.

Even jet aircraft, flying at 5 to 8 miles above the earth's surface can create clouds. Look up and you can often see their CONdensation TRAILS (or CONTRAILS). Because of their altitude, these trails immediately become cirrus clouds. If the air is dry at the contrail's altitude, the contrail will disappear in moments. If the air is moist (or if other cirrus clouds are present), the contrails may spread across parts of the sky and last for a long time. Have you ever seen ten contrails at the same time? Twenty?

Finally, there are clouds that appear to be banded (like the altocumulus stamp in the center of the "Cloudscapes" sheet on page 1). The cloud forms where the air is rising and it evaporates where the air is sinking. Thus, this banding is really linked to a wave in the sky that lies perpendicular (at right angles) to the bands in the cloud. This type of cloud is called undulatus (from Latin) because it undulates or waves.

Cloud Watching

Looking up is actually one of the best ways to make your students avid cloud watchers. And if you model this "hobby," your students will gladly join you. It's really quite easy. Just try it and you'll be amazed at the ever-changing sky show overhead. Clouds can last for hours or they can form and/or transform before your eyes.

Typically, layered-type clouds are present early in the day. As the day progresses (and the ground and air become heated), puffy clouds form. By late afternoon or early evening, layered clouds return. Of course, in some places and at different times of the year, the clouds may not follow this general script. Here are four images showing how the clouds changed in the Rockville, Maryland area on October 16-17, 2004.

You have probably seen clouds that have shapes of things familiar to us. We've showcased an image of a cloud that looks like a flying elephant. But, many people have reported seeing fish, birds, dragons and other shapes. Nephelococcygia (neph-e-lo-coc-cy-gia) is a word used to describe this cloud watching activity.

Clouds are typically white on top because of reflected white sunlight and darker on the bottom where the cloud casts its shadow. Around sunrise and sunset, pollution and dust may cause orange and pink colors to become more visible. This can create very colorful clouds. Sometimes, sunlight passing through ice crystal cirrus clouds may cause a colored ring or halo to form. A similar coloring may sometimes be seen at the 3 o'clock and 9 o'clock positions relative to the sun. These are known as sundogs.

If sunlight shines through thin clouds that are composed of water droplets instead of ice, a corona--a series of colored rings--may encircle the sun. It's easy to see this in the image to the right, because part of a roof blocked the sun.

Falling raindrops (especially with the sun on the opposite side of the sky) can lead to the appearance of a rainbow. The raindrops, through a series of internal reflections and other optical factors, split sunlight into its component colors. If the angle made between the sunlight, the raindrops and your eyes is just right, you'll see the bow. Typically, this happens either early or late in the day.

Clouds On The Web

Many TV stations, ski resorts, environmental sites and others now have "skycam" (sky cameras) posted at their web site. During daylight hours, these can provide students an opportunity to see the weather in other places and match cloud views from space with views from Earth (see links page (1)).

Clouds from Space

Meteorologists can also view clouds from space, thanks to weather satellites and past space shuttle orbital missions. By looking at visible satellite images, we see the clouds and Earth as we might if we were to be in space looking down at the Earth. Infrared images measure the heat energy given off by clouds, the ground and water surfaces. (See web links page for additional information about interpreting satellite images. (1))

Clouds and Climate

During the day, clouds block incoming sunlight and often lead to lower daytime temperatures. At night, clouds, especially those at low and middle levels, act like a blanket, trapping heat and warming the air. Over long periods, changes in cloud cover across the globe or in certain places can affect the earth's climate.

To help understand these changes, scientists at NASA, NOAA and many universities are studying clouds and climate. Deborah Vane, our featured "Meet the Scientist" is working with colleagues in other places to develop a cloud monitoring satellite--called CLOUDSAT. Scientists expect to launch this satellite in the spring of 2005.

Safely Watching The Sky

It is always important to take care of your eyes when sky watching. Meteorologists and medical doctors know how much damage bright sunlight can do our eyes.

For general, bright light conditions, you can use proper sunglasses or tinted lenses to help protect your eyes. But, don't think that sunglasses will let you look directly at the sun!

A good rule to follow is to ALWAYS block the sun when you sky watch. You can use a natural or human-made object (e.g., a tree or a building) or you can simply hold your fist up at arm's length and use it to block the sun.

Toward sunrise or sunset or when thick clouds are present, you may be able to briefly look toward the sun without these protective measures. But, if you aren't sure that it is safe to look toward the sun, it's best not to.


NEVER look directly at the sun. Always use your hand or another object to shade your eyes.

Level Pre-A

Main Concepts: There are many different types of clouds. Some are puffy. Others are flat. Rain and snow are inside clouds.

Picture Activity

Ask where WHY FLY, FLY-pothesis and SCIENCE are in this issue of Science Weekly. They are in, on or flying around the clouds. SCIENCE is sitting in a stratus (flat) cloud on the ground (called fog); WHY FLY is on a cumulus (puffy) cloud; FLY-pothesis is flying high in the sky by cirrus (wispy) clouds. Some clouds have rain and snow inside them.


Go over all the pictures together first--rain, trail, sail, pail and brain. Have students trace over the first "ai" and then fill in the blank spaces with the same two letters. Note that "ai" sounds like "ay" in day.


Use the template shown in the student issue to create mini-books with your students. Lead students through the folding activity step by step; adults need to score, cut and refold the booklet. 1. Take an 8-1/2" x 11" sheet of paper and fold it hot dog style along line E-F. Then fold in half (E to F) and in half again (D to F) to create 8 sections. Open and lay the sheet flat. Carefully score line A-B with scissors. Then separate A-B or cut, as needed. 2. Refold hot dog style. Separate the scored section pulling D to the back and C forward. 3. Close by folding E to C, C to F, and then F to D and you have a 6-page mini-book. 4. Once the books are made, students can draw pictures of the clouds they see.

Weekly Lab

You need: wax paper sheets, pipettes, plant misters, paper towels and sponges. (If you do not have pipettes, you can use coffee stirrers or straws.) Give each student a sheet of wax paper (around 12" x 12") and a pipette. Ask students not to use the pipette until instructed to do so.

Use a plant mister to spray water droplets onto the wax paper. Spray about 3 to 5 times or until there is a visible raindrop-size distribution. Be careful not to spray too much or you will saturate the wax paper. NOTE: If the wax paper gets too wet or tears, throw it away, wipe up the area and provide the student with a new sheet of wax paper.

Ask, "What can you tell me about your raindrops?" Encourage all answers--round from on top, round from the sides, different sizes, reflect overhead lights, have air bubbles inside them, and see through them.

Introduce the word transparent and explain that this means being able to see through something. Windows, for example, are transparent.

Ask students to "play with their raindrops" to discover how raindrops may get bigger. They can do this by moving the drops with their pipettes. Note that some students may blow on the drops, use the pipettes to create wind to blow the drops around, or draw the drops up into their pipette and then push the water out onto another drop.

Ask "How did your raindrops get bigger?" " What happened when one raindrop came very close to another?"

Much like two magnets of opposite charge will "jump" at each other when they are close, raindrops want to merge with their neighbors. Surface tension, the skin on a water drop, attracts the skin on the other. Surface tension acts like our skin and keeps what's inside together.

To extend this activity, try the experiment with salt water. Ask, "Did the salt water behave the same way as tap water?" You can also let the raindrops dry on the wax paper and have students observe the raindrop markings. Ask, "Are all the drops the same size? Are all the drops round?"


We have filled the rain gauge with 6 inches (15 centimeters) of water. Answer: Using a "standard" paper clip, the gauge should be about 5 clips full. If you use clips that are a different size, have students measure to the closest whole paper clip. Then, students should use a ruler to measure to the nearest inch.

Meteorologists (people who study about the weather) are interested in how much rain and snow falls. They use a rain gauge (a tube-shaped instrument) and a ruler to measure the rain and snow. This data helps people understand what types of plants can live in a place and how water fills rivers and streams.

To extend this activity, you can leave a plastic cylindrical jar outside on a rainy day and then measure how much rain has fallen (usually in parts of an inch). If it has snowed, you can use a ruler (meter stick or yardstick) to see how deep the snow is.


Answers: From left to right, the clouds are cirrus, cumulus and stratus. (Refer to the "Cloud Type Table" on our links page (1)).

Bringing It Home

With adult supervision, students can make it rain at school or at home. A plant mister or a garden hose helps to create raindrops of many different sizes. Students can watch the drops float and fall based on their size. They can also watch the patterns as the drops land on a sidewalk or playground.

Level A

Main Concepts: There are many different types of clouds. Some are puffy. Others are flat. Rain, snow and hail form inside and then fall from clouds.


Go over all the pictures together first--rain, trail, sail, pail, brain and braid (or plait). Have students write the beginning and ending letters of these "ai" words. Note that "ai" sounds like "ay" in day.

To extend this activity, have students work in small teams to see who can make the longest list of "ai" words (e.g., sail, rail, wait, pain, plain, afraid, Spain, refrain, chain).

NOTE: the "ai" can appear anywhere in the word.

Writing In Science

See TN Level Pre-A for instructions on making the minibooks. Once the mini-books are made, students should observe clouds on five different days and record their observations (cloud picture and cloud name).

Weekly Lab

See TN Level Pre-A. Introduce measuring the size or diameter (distance across the middle) of raindrops. Ask students, "Is it easier to measure to the nearest whole number in inches or centimeters? Which scale should we use to measure our raindrops?"

Answer: Either scale would work. Centimeters is preferred for measuring smaller drops because there are more divisions.

To extend this activity, make a class bar graph using only two observations from each student. The x-axis should range from 0 cm to 10 cm or 0 inches to 5 inches. Zero is included because any observation less than 1/2-inch or 1/2-centimeter would be closest to zero.

Record the data on graph chart paper. If necessary, expand the chart vertically by adding another sheet of chart paper.

Discuss the graph with students. You will likely find that most drops are smaller than 3 centimeters.


See TN Level Pre-A.

Answer: We have filled the rain gauge with about 6 inches (15 centimeters) of water.

To extend this activity, you can set up rainfall measuring stations using plastic cylindrical jars around your classroom. Label these A, B, C ... and fill each with a different amount of water. Place a ruler at each station.

Create a data sheet for students to use as they move around the room measuring the water in these miniature rain gauges.


Answers: From top to bottom, the clouds are cirrus, cumulus and stratus. This arrangement is how the clouds would appear in the sky. (Refer to the "Cloud Type Table" on our links page (1)).

Bringing It Home

See TN Level Pre-A. Once the drops have landed, students can also watch how they evaporate (how water transforms from a liquid to a gas).


Cumulonimbus clouds can grow to heights of more than 12 miles.

Level B

Main Concepts: There are many different types of clouds, each with different attributes. Some clouds have multiple attributes. Clouds form under different weather conditions. Cloud colors (white vs. grey) are due to reflection and shadowing.


Words are found horizontally and vertically. No words are shown backwards or diagonally.

Weekly Lab

You need (for each team): two small cotton balls, two wax paper sheets, a pipette, a small cup filled with water, a pencil and a data-recording worksheet.

Clouds become saturated with (full of) water when condensation (process by which water vapor changes to liquid water) occurs. But rising air currents keep the raindrops suspended in the cloud. The cotton ball is like a cloud except that it lacks rising air currents. Once the amount of water in the cloud exceeds the cloud's capacity to hold the water, raindrops fall.

This activity involves controlling variables. It is important that students practice with the pipettes before beginning the activity.

Variables could include any or all of the following: differences in the pipettes; how the students squeeze the pipettes; how the students count the drops; how they hold the cotton ball; and variations in the cotton balls.

For "Trial 1," the predictions would be more like "guesses." By "Trial 2," students will have begun to integrate their knowledge of the pipettes and cotton balls to make more accurate and reasonable predictions.


In this activity, data from each team's weekly lab is combined into a class graph. One way to do this is to create a human graph in which each student becomes the data.

Use folded index cards, construction paper or manila folders to create a set of labels for the human graph. Place these in an open area behind which students can easily line up in columns. If your floor is tiled, use the tiles as column guides.

Have students line up behind the label that matches their actual count of raindrops as a rainmaker.

Once the students have lined up, record the count for each column on chart paper.

Have students record the data in their science notebooks and make a bar graph.

Have students write one question about their graph. Discuss questions and answers with the class. You may also want to extend the activity by asking questions such as these--How many students reported between 30 and 39 (30s) raindrops? How many students reported more than 50 raindrops? What was the difference (range) between the most (maximum number of) raindrops and the fewest (minimum number)?

Writing In Science

It is extremely important for scientists to record the date and time of an observation. Without this information, it may not be possible to make sense of the data.

To extend the activity, have students record data for a second week. Based on past cloud and weather data, students should try to predict the upcoming weather each day. As a class, discuss predictions and what actually occurred.


Answers: From left to right, the clouds are cirrus, cirrocumulus, cumulus, stratocumulus, stratus and cumulonimbus.

Bringing It Home

In addition to the cloud types found in the sky, students may see clouds in their bathrooms, over a pot of boiling water in the kitchen, atop a smoke stack at a factory or power plant, or coming out the exhaust of a car on a cold morning. Students may also have seen the cloud exhaust from a high-flying jet aircraft (see TN BACKGROUND--contrails, page 2, bottom left).

If students have a chance to fly, they may get to see clouds from the top looking down.

To extend the activity, students can photograph the sky and help to create a cloud bulletin board. Also, see the Letter From the Editor starting on page 1.


Clouds, called nebula (neb-u-la), can exist in space. Clouds can also appear on other planets.

Level C

Main Concepts: There are many different types of clouds, each with different attributes. Some clouds have multiple attributes. Cloud names are combinations of root words, prefixes and/or suffixes. Clouds form under different weather conditions. Cloud colors (white vs. grey) are due to reflection and shadowing.

Weekly Lab

You need (per student): one white paper plate, two sheets of blue construction paper, scissors and a pencil.

This activity involves both math and science and tries to replicate how meteorologists estimate the amount of sky that is covered by clouds.

It is important to realize that by looking up at the celestial dome, we see different things overhead than we see near the horizon. Overhead, we see cloud bases; near the horizon, we may see cloud bottoms, but we also see the sides of clouds. For this reason, skies near the horizon may appear to be cloudier than they really are.

There are many possible ways to position the wedges and pieces in steps 4 to 6. Most students should be within 1/8 of the sky cover estimated by their classmates (step 8).


Answer: $4.45. Students should initially estimate $4.00. They should round $5.55 to $6.00 and subtract from $10.00.

You can extend this activity by having FLY-pothesis purchase additional sheets of stamps. All purchases have to be in whole sheets of 15 stamps.

Writing In Science

In addition to the artistic value of this activity, there is a student assessment component. Through writing and drawings, students will demonstrate their mastery of cloud identification.

You may want to consider creating a cloud stamp wall and post some of the images crafted by the students. Arrange these by altitude, just as the U. S. Postal Service did with its stamps.


Following the WRITING IN SCIENCE assessment, this activity keys on the understanding of the Latin root words, prefixes and suffixes. By creating, drawing and describing a fictitious type of cloud through the creative use of these word parts, students will show their understanding of cloud names.


With your students, define the terms of carrying out this word-finding activity. For example, you can limit words to 3 letters or more; you can decide whether or not to accept proper names; and you can time the activity.

There is no answer key, but students can challenge words by verifying them in a dictionary or other reference source. R, S and T are the 3 consonants not found in this word.

To extend this activity, consider creating a master class word list. Don't be surprised if you find hundreds of words hidden in nephelococcygia.

Level D

Main Concepts: There are many different types of clouds, each with different attributes. Some clouds have multiple attributes. Cloud names are combinations of root words, prefixes and/or suffixes. Clouds form under different weather conditions. Cloud colors (white vs. grey) are due to reflection and shadowing. There can even be clouds of smoke, pollution, dust and volcanic ash. Clouds can be found on other planets and in space.


See TN Level C--VOCABULARY. After discussing potential rules for the activity with your class, challenge them to find only words that have 4 letters or more.

Weekly Lab

Nephanalysis (cloud analysis) is a map showing cloud information. Typically, it separates areas that have few clouds from partly cloudy and mostly cloudy skies.

From a series of nephanalyses, it is possible to extrapolate (use the past information to project a future value or position) to create a cloud forecast map.

The analysis can also be done using satellite (something that orbits something else) images. For this activity, a set of satellite images from a National Oceanic and Atmospheric Administration (NOAA) satellite, that is about 22,000 miles above the Earth, has been posted at our web site links page (see Internet Resources, page 8).

On November 2rid, there was a bright area of clouds over Louisiana. On the 3rd, it was located over eastern Tennessee. On the 4th, it was over the New York-Pennsylvania area. If you can transfer this bright cloud information to a single map graphic (e.g., overhead or computer display), this may help students better see the day-to-day progression of the bright cloud area. Then ask students, "Where do you think this bright cloud area was located on November 5th?"

Answer: parts of eastern Canada. (See web links page for image for November 5, 2004.)

To extend the activity, visit the Plymouth State College web site at Click on "Make your Own" (left menu) and then "Satellite Imagery-WXP GOES." Then select different satellite image types (including infrared or heat-based, which is the type shown here) for different places. Print and post images, as needed. NOTE: Times shown on the images are Greenwich Mean Time (GMT) or Z time, which is 5 hours ahead of Eastern Standard Time (EST), or 8 hours ahead of Pacific Standard Time (PST).

You can also view "animated GIFs" and "MPEGs" (look halfway down the left menu). Although these are low-resolution animations, some show as much as 72 hours of images. This will help your students see how wind patterns move the clouds and how extrapolation can be used as a forecasting tool.

Even if you and your students can't fully understand the image content, simply looking at the images will generate interest in learning more about this type of data.


Here is a chance to find out about your state's official symbols. In addition to learning what the symbols are, consider having students find out how the symbols came into being.

Writing In Science

No state has an official state cloud. This activity keys on developing and implementing an election strategy (and its related campaigning opportunities) to decide upon a candidate state cloud. Then, students can develop a strategy for working within political channels to obtain a state cloud designation.


Tallying election results, to ensure that the count is fair, is something that has been showcased in two recent national presidential elections. It is just as important in any election. Having two or more people count and recount the votes will generally address this concern. Once the votes are counted, they can be posted and graphed in easy-to-understand formats.


See TN Level C.

Meet the Scientist

We discovered Deborah Vane by searching the Internet for scientists who were studying about clouds. We found some scientists who fly airplanes into clouds; others who look at clouds from the ground up; and still other scientists, like Ms. Vane, who study clouds from space. (Refer to Internet Resources, page 8, to find direct links to NASA's space shuttle and MODIS (3) high-resolution images.)


"Partly cloudy" means that clouds cover more than half the sky. but not the whole sky.

(3) MODIS = MODerate resolution Imaging Spectroradiometer.

Level E

Main Concepts: There are many different types of clouds, each with different attributes. Some clouds have multiple attributes. Cloud names are combinations of root words, prefixes and/or suffixes. Clouds form under different weather conditions. There can even be clouds of smoke, pollution, dust and volcanic ash. Clouds can be found on other planets and in space. It is possible to study and track clouds using weather satellites.


See TN Level C--VOCABULARY. After discussing potential rules for the activity with your class, challenge them to find only words that have 5 letters or more.

Weekly Lab

See TN Level D. In addition to looking at infrared images, compare and contrast infrared, visible, and water vapor images.


See TN Level D.

Writing In Science

See TN Level D.


See TN Level D.

To extend this activity, students may want to interview a sampling of other students to obtain data about WHY they voted for a particular cloud.


To find out information about some of these questions (and others the students may pose), students can use classical library reference sources; key on resources provided in these TNs; and make some focused searches on the Internet. If students are not able to focus their search, tell them that it is often a good idea to search for one word first and then narrow their search by adding key words. For example, if the student is looking for information about how clouds float, a search for "clouds" alone will be too general. Have them try searching for "weight of clouds," "size of clouds," or even "how heavy is a cloud." It may take several tries to narrow their search sufficiently.

Another approach might be to find a weather web site that has lots of information and then search within that web site for a specific topic.

Meet the Scientist

See TN Level D.


A cumulus cloud occupying a volume of one cubic mile can weigh about 500 tons! A cumulonimbus cloud occupying a volume of 1,000 cubic miles often weighs more than 1 million (1.0 X [10.sup.6]) tons! Rising air currents, some as fast as 50 mph or more, keep the clouds afloat?

Weekly Resources

Helpful Sources for Planning Your Science Weekly Classroom Activities

Recommended Resources

* Allaby, Michael. How The Weather Works. Pleasantville, NY: Reader's Digest Association, Inc., 1995

* Barrett, Judi. Cloudy With a Chance of Meatballs. New York: Aladdin Books, 1978

* Brandley, Franklyn M. Down Comes The Rain. New York: HarperCollins Publishers, 1997

* Day, John A. Day and Vincent Schaefer. Clouds and Weather--A Petersen First Guide. New York: Houghton-Mifflin Company, 1991

* De Paola, Tomie, The Cloud Book, New York: Holiday House, 1975

* DeWitt, Lynda. What Will The Weather Be. New York: HarperCollins Publishers, 1991

* Eden, Philip. The Weather and its Secrets. Pleasantville, NY: Reader's Digest Association, Inc., 1998

* Greene, Carol. Hi, Clouds. Chicago, IL: Children's Press, 1983

* Locker, Thomas. Sky Tree. New York: HarperCollins Publishers, 1995

* Shaw, Charles G. It Looked Like Spilt Milk. New York: HarperCollins Publishers, 1947

* Supraner, Robyn. (I Can Read About) Weather. New York: Troll Communications. 2001

(1) Many of the cloud images and web links referenced here may be found at the Science Weekly web site at vol21.2.clouds.html.

(2) Images courtesy of H. Michael Mogil, used by permission.

Dear Subscribers

Do you really know the "scientific method?" If not, just conduct a search for it on the Internet. The last time I did this, I had obtained more than 4.0 million "hits." Maybe the process isn't as easy as we thought!

Perhaps one of the better discussions can be found at the Discovery School's web site courtesy of Janice van Cleave (see Internet Resources, page 8). While older students and adults could use the method that she describes best, younger students, even those at grades 5 and 6, might have a hard time carrying out such a rigorous approach.

However, in her description, she notes "... Research is the process of collecting information from your own experiences, knowledgeable sources, and data from exploratory experiments." This is where K-6 students may actually excel over their grade 7-12 counterparts.

Young scientists can be eager observers. Many of the activities that are done in these early grades key on looking at the world around them. It isn't uncommon to look at trees, leaves, plants, bugs and even rocks. Moon watching is a mainstay in many elementary schools.

But, there is almost no scientific topic that provides an opportunity for observing, in general, and observing change QUICKLY, than weather. And within that discipline, cloud watching is unparalleled.

Look to the sky and observe the clouds. Look again in 5 minutes ... sometimes even within seconds ... and the sky has transformed. Watch the sky on a windy day or when thunderstorms are developing and you can even see the clouds changing their shapes.

If you and your students (or your child) are already avid observers, hopefully this Science Weekly topic will help you build on those skills. If you are not yet into watching the natural world EVERY DAY, we hope that this subject may become your springboard.

And, if your eyes and brain are your primary documentation modes, you might even think about a sky or nature journal (drawing and/or writing modes) or my favorite--a digital camera.

In the past month alone, I have captured images of clouds, trees in full fall regalia, wooly caterpillars, preying mantises, slugs (ugh!), and even time exposures of the lunar eclipse. And on a recent plane trip, I took time to view the Earth and sky from 35,000 feet. River valleys, power plant smoke stacks (with plumes), forests and even the layout of the airport runways all captured my attention.

Observations alone won't make your students effective scientists. But good observational skills can go a long way to making them become more curious about their world and want to learn more about it.

This edition of Science Weekly is designed to foster those improved observational skills not only at the elementary level but throughout their lives.


H. Michael "Mike" Mogil Editor-in-Chief

Have you ever been inside a cloud? You may have walked through one on a foggy day. You might have even created one the last time you took a shower.

A cloud is a visible collection of water drops, ice crystals, or a mixture of both that is suspended in the air.

Cloud Naming

Meteorologists classify clouds into three basic types. Each has different attributes or shapes. In 1803, Luke Howard, a British chemist, named the clouds. To name the clouds, he matched their shapes and altitudes to Latin root words. Some clouds have more than one attribute. If a cloud is layered and puffy it is called stratocumulus (stra-to-cu-mu-lus).

He also used prefixes and suffixes to further define the many other cloud types that he observed. Alto- (al-to-) means high, cirro-(cir-ro-) are ice crystal clouds, and -nimbus (-nim-bus) means rain. Thus, altocumulus (al-to-cu-mu-lus) is a puffy cloud at high altitude.

Clouds form when moist air rises. Sometimes this is caused by winds blowing up and over mountains. At other times, cold and warm fronts can push air upwards. Thunderstorm clouds, called cumulonimbus, (cu-mu-lo-nimbus) form when air rises very quickly.

Cloud Watching

Clouds may have shapes of things familiar to us. Above, is a cloud that looks like a flying elephant. Nephelococcygia (neph-e-lo-coc-cygia) is a word used to describe looking for animal and other shapes in the clouds. Clouds are often whiter on top and darker on the bottom. This is because the cloud top reflects white sunlight and the cloud bottom lies in its shadow.

SCIENCE SAYS ... When looking at clouds never look directly at the sun. Always use your hand or another object to shade your eyes.


Clouds, called nebula (neb-u-la) can exist in space. Clouds can also appear on other planets


Cumulonimbus clouds can grow to heights of more than 12 miles.


There are also clouds of dust, smoke and volcanic ash.


Clouds at sunrise and sunset may be pink, orange or red because of pollution in the air.


[ILLUSTRATION OMITTED] cirrus wispy 4 to 8 miles high

[ILLUSTRATION OMITTED] cumulus puffy Bases 1 mile high

[ILLUSTRATION OMITTED] stratus layered Close to ground;
 if touching ground
 known as fog

Weekly lab

How Cloudy is It?

To determine how cloudy it is, meteorologists divide the sky into eight parts, much like a pizza pie. Then, they estimate how much of the sky is covered by clouds and how much isn't. To estimate cloud cover, try the following method.

You need (per student): one white paper plate, two sheets of blue construction paper, scissors, and a pencil

Step 1: Using your pencil, trace the outline of a white paper plate onto two pieces of blue construction paper.


Step 2: Cut out both circular patterns.


Step 3: Place the paper plate on top one of the blue paper circles to represent a cloudy sky; the other blue paper represents the opposite or a clear blue sky.


Step 4: Cut the paper plate in half, making two semi-circles. Then cut each of these in half, making 4 equal wedges. Cut each again, so you have 8 equal wedges, just like a pizza pie. Put four wedges on each blue circle.


Step 5: On one circle, put all four wedges together to make a semi-circle; on the other, place the pieces randomly, without overlapping. Compare what the two skies look like.


Step 6: Remove two of the wedges from each sky. On one sky keep the two wedges together, covering one-fourth of the blue circle. On the other, cut up the 2 remaining wedges into smaller cloud-shaped pieces and place them randomly across the sky.


Step 7: Again, compare what the two skies look like. This demonstrates how meteorologists estimate cloud cover.


Step 8: Next, go outside when clouds are present and make your own estimation of sky cover in eighths. Record this information in your cloud journal.


Step 9: Discuss your estimate with that of your classmates.



"Partly cloudy" means that clouds cover more than half the sky. But not the whole sky.


FLY-pothesis is going to the Post Office to buy some cloud stamps. He's going to invite some friends to a surprise birthday party for WHY FLY. He needs 15 stamps for the invitations. This costs $5.55 (15 x $0.37).

If he gives the postal clerk ten dollars, how much change will he receive?

I estimate that I will get ...

$--.--change back.


High-flying jet aircraft can create cirrus clouds? Just look up and you can often see lines of cirrus clouds criss-crossing the sky. These types of clouds are called contrails (con-trails).

Writing in Science

Create your own sheet of 4 cloud stamps on white paper. Divide a sheet of paper into 4 equal parts. Design four different cloud stamps and write a brief description of each. Be sure to include the cloud names and don't forget the 37 cents postage on each of your stamps.

On October 4, 2004, the U.S. Postal Service issued a sheet of 15 cloud stamps. Many scientists wrote to the Postal Service, 15 years ago, to request these stamps. In addition to the images, each stamp has a brief Description of its cloud.


"I like these new cloud stamps!"


At a height of 5,148 ft. (1,569 m.), Mt. Wai'ale'ale, Kauai, Hawaii, has up to 350 rainy days per year. Almost perpetual cloud cover at the peak of the mountain helps produce about 500 inches (12.7 m.) of rain per year.


Clouds can sometimes block so much sunlight that daytime "turns to night." Once a thunderstorm in Birmingham, Alabama actually caused automatic streetlights to come on around 4:00 p.m.


Use Luke Howard's prefixes, suffixes and root words to create new clouds. For example, you might create an alto-cumulo-nimbo-stratus cloud. Once you create the name, draw and describe your new cloud.



How many words can you find hidden in this large word? Nephelococcygia (neph-e-lo-coc-cy-gia) is a word that describes looking at clouds and finding shapes of familiar things in them. You may need a second sheet of paper if your word list gets very long.
COPYRIGHT 2004 Science Weekly, Inc.
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2004 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Publication:Science Weekly
Date:Nov 17, 2004
Previous Article:Lewis and Clark.
Next Article:Zoos.

Related Articles
Global warming: cloud patrol. (Earth Science: Global Warning * Clouds).
Cloud categories. (Hands-On Activity).
Mapping the frozen sky; study looks at clouds from both sides now. (This Week).
Fuse survey. (Senior Division).

Terms of use | Privacy policy | Copyright © 2020 Farlex, Inc. | Feedback | For webmasters