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Vol. 21, No. 2


OW?? DID YOU KN so clouds There are al e and of dust, smok h. as ic an volc

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

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.

Cumulus cloud photo © H. Michael Mogil, used by permission.

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). DID YOU KNOW ?? DID YOU KNOW?? Cumulonimbus clouds can grow Clouds, called to heights of more nebula (neb-u-la), than 12 miles. can exist in space. Clouds can also appear on other planets. Horsehead Nebula / IC434, Photo by N. A. Sharp/ NOAO/ AURA/ NSF, used by permission

Level C

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 SCIENC bottom lies in its shadow. E SCIENCE SAYS… When looking at clouds never look directly at the sun. Always use your hand or another object to shade your eyes.


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 Step 2: Step 3:

Step 4:

Step 5:

Step 6:

Step 7: Step 8:

Step 9:

NOW?? DID YOU K dy” means “Par tly clou cover more that clouds e sky. but th than half le sky. not the who

of a white paper plate onto two pieces of blue construction paper. blue Cut out both circular patterns. construction paper paper plate 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. Cut the paper plate in half, making two scissors 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. Step 1 Put four wedges on each blue circle. 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 2 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 cloudStep 3 shaped pieces and place them randomly across the sky. Again, compare what the two skies look like. This demonstrates how meteorologists estimate cloud cover. Next, go outside when clouds are Steps 4 and 5 present and make your own estimation of sky cover in eighths. Record this information in your cloud journal. Discuss your estimate with that of Step 6 your classmates.

SCIENCE WEEKLY, Level C (ISSN 8756-1788), November 17, 2004 is published monthly in October, January and May; twice-monthly in November, December, February and April; and three times in March. Copyright © 2004 (Level C) CAM Publishing Group., Inc., 2141 Industrial Pkwy., Suite 202, Silver Spring, MD 20904-7824 U.S.A. (301) 680-8804 (800) 4-WEEKLY. Classroom subscription price: (minimum 20 subscriptions to same address): $4.95 per student, per school year; $3.80 per student, per semester. Orders less than 20 subscriptions: $19.95 per student, per year, $14.95 per student, per semester, payable in advance. Periodical postage paid at Silver Spring, Maryland and additional mailing offices. Postmaster: Send address changes to Science Weekly, Level C, P.O. Box 70638, Chevy Chase, MD 20813-0638. Visit our web site at C-2

Math How much change will I get?

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?

DID YOU K NOW?? High-flying je t aircraft can create cirr us clou ds? Just look up and yo u can often see lines of ci rr us clouds cris s the sky. Th -crossing ese types of clouds are contrails (c called on-trails).

I estimate that I will get… $_______.______ change back.

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.

CLOUDSCAPES © 2004 U.S. Postal Service

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 SCIENCE SAYS… description “I like these new of its cloud. cloud stamps!”

?? DID YOU KNOW 8 ft. 14 At a height of 5, le’ale, ’a ai W t. M (1,569 m.), to up s ha Kauai, Hawaii, . ar ye r pe ys 350 rainy da cover ud clo l ua et rp pe Almost the mountain at the peak of out 500 inches ab e uc helps prod per year. (12.7 m.) of rain


DID YOU KNOW?? Clouds can sometimes blo ck so much sunlight that day time “turns to night.” Once a thunderstorm in Birming ham, Alabama actually caused automatic streetlights to come on around 4:00 p.m .

Published by CAM Publishing Group, Inc., Silver Spring, MD • Publisher, CLAUDE MAYBERRY, JR. • Editor - in -Chief, H. MICHAEL MOGIL • • Writer, BARBARA G. LEVINE • Artist, LINDA KING • Graphic Design and Production, LINDA KING • • Materials in this issue may not be reproduced in whole or in part in any form without special permission from the publisher. C-3

Comprehension 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.

cirrus cumulus stratus altocumulo-nimbus

Vocabulary 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.



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