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He also used prefixes and suffixes to furtherdefine the many other cloud types that heobserved. 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 highaltitude.

Clouds form when moist air rises. Sometimesthis is caused by winds blowing up and overmountains. At other times, cold and warmfronts can push air upwards. Thunderstormclouds, called cumulonimbus, (cu-mu-lo-nim-bus) form when air rises very quickly.

Cloud WatchingClouds may have shapes of things familiar tous. Above, is a cloud that looks like a flyingelephant. Nephelococcygia (neph-e-lo-coc-cy-gia) is a word used to describe looking foranimal and other shapes in the clouds.Clouds are often whiter on top anddarker on the bottom. This isbecause the cloud top reflectswhite sunlight and the cloudbottom lies in its shadow.

SCIENCE SAYS… When looking at cloudsnever look directly at the sun. Always use your

hand or another object to shade your eyes.

SCIENCE

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Clouds

®Vol. 21, No. 2

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

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

Cloud NamingMeteorologists classify clouds into threebasic types. Each has different attributes or shapes. In 1803, Luke Howard, a Britishchemist, named the clouds. To name theclouds, he matched their shapes andaltitudes to Latin root words. Some cloudshave more than one attribute. If a cloud islayered and puffy it is called stratocumulus(stra-to-cu-mu-lus).

Level C

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

DID YOU KNOW??

Clouds at sunriseand sunset

may be pink, orange

or red because of

pollution in the air.

DID YOU KNOW??

Clouds, called

nebula (neb-u-la),

can exist in space.

Clouds can also

appear on otherplanets.

DID YOU KNOW??

There are also clouds

of dust, smoke and

volcanic ash.

Horsehead Nebula/ IC434, Photo by N. A. Sharp/ NOAO/ AURA/ NSF, used bypermission

DID YOU KNOW??Cumulonimbus

clouds can grow toheights of morethan 12 miles.

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.

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 threetimes 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: Sendaddress changes to Science Weekly, Level C, P.O. Box 70638, Chevy Chase, MD 20813-0638. Visit our web site at www.scienceweekly.com.C-2

Weekly LabHow 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 byclouds 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

blue construction

paper paper plate

scissors

Step 3

Steps 4 and 5

Step 2

Step 1

Step 6

DID YOU KNOW??

“Partly cloudy” means

that clouds cover more

than half the sky. but

not the whole sky.

Math

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.DISTINGUISHED

ACHIEVEMENTAWARD WINNER

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Create your own sheet of 4 cloudstamps on white paper. Divide a sheetof paper into 4 equal parts. Designfour different cloud stamps and write abrief description of each. Be sure toinclude the cloud names and don’tforget the 37 cents postage on each ofyour stamps.

Writing in ScienceOn October 4, 2004, the U.S. PostalService issued a sheet of 15 cloudstamps. Many scientistswrote to the PostalService, 15 years ago, torequest these stamps.In addition to theimages, each stamphas a briefdescriptionof its cloud.

CLOUDSCAPES © 2004 U.S. Postal Service

SCIENCE SAYS…“I like these new cloud stamps!”

DID YOU KNOW??

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.

DID YOU KNOW??Clouds can sometimes block so much sunlight that daytime

“turns to night.” Once athunderstorm in Birmingham,

Alabama actually causedautomatic streetlights to

come on around 4:00 p.m.

FLY-pothesis is going to the Post Office to buy somecloud 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 KNOW??High-flying jet aircraft can create cirrus clouds?Just look up and you canoften see lines of cirrusclouds criss-crossing the sky. These types of clouds are called contrails (con-trails).

I estimate that I will get…

$_______.______ change back.

How muchchange will

I get?

Use Luke Howard’s prefixes, suffixes and root wordsto create new clouds. For example, you might createan alto-cumulo-nimbo-stratus cloud. Once you createthe name, draw and describe your new cloud.

Comprehension

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VocabularyHow many words can you find hidden in this largeword? Nephelococcygia (neph-e-lo-coc-cy-gia) is a wordthat describes looking at clouds and finding shapes offamiliar things in them. You may need a second sheetof paper if your word list gets very long.

N E P H E L O C O C C Y G I A

cirruscumulusstratus

alto-cumulo--nimbus