why does it thunder and lightning? (tell me why, tell me how)

TELL ME WHY, TELL ME HOW

DARICE BAILER

WHY DOE IT

THUNDER ANDLIGHTNING?

S

Job Tell Me Why - Why Does It Thunder and Lightning? Upon approvalplease signFile Location Deltaserver 1

009 LKH DateAX: 8699851

We do not accept responsibility for any error,defect or inaccuracy which is not noted onthe proof. Therefore customers are advisedto thoroughly check and examine the proofprior to authorising the digital files for printing.

1st

2nd3rd

4th

5th6th

Thunder_INT_FINAL_q7.qxd:Birds Sample 4/8/10 10:37 AM Page 1

Special thanks to Dr. Don MacGorman, a physicist at the NOAA/National Severe Storms Laboratory in Norman, Oklahoma, for hisconsultation in helping explain the latest theories of thunder and lightning to children.

Copyright © 2011 Marshall Cavendish Corporation

Published by Marshall Cavendish BenchmarkAn imprint of Marshall Cavendish Corporation

All rights reserved.No part of this publication may be reproduced, stored in a retrieval system or transmitted, in any form or by any means, electronic,mechanical, photocopying, recording, or otherwise, without the prior permission of the copyright owner. Request for permissionshould be addressed to the Publisher, Marshall Cavendish Corporation, 99 White Plains Road, Tarrytown, NY 10591. Tel: (914)332-8888, fax: (914) 332-1888. Website: www.marshallcavendish.us

This publication represents the opinions and views of the author based on Darice Bailer’s personal experience, knowledge, andresearch. The information in this book serves as a general guide only. The author and publisher have used their best efforts inpreparing this book and disclaim liability rising directly and indirectly from the use and application of this book.

Other Marshall Cavendish Offices:Marshall Cavendish International (Asia) Private Limited, 1 New Industrial Road, Singapore 536196 • Marshall CavendishInternational (Thailand) Co Ltd. 253 Asoke, 12th Flr, Sukhumvit 21 Road, Klongtoey Nua, Wattana, Bangkok 10110, Thailand •Marshall Cavendish (Malaysia) Sdn Bhd, Times Subang, Lot 46, Subang Hi-Tech Industrial Park, Batu Tiga, 40000 Shah Alam,Selangor Darul Ehsan, Malaysia

Marshall Cavendish is a trademark of Times Publishing Limited

All websites were available and accurate when this book was sent to press.

Library of Congress Cataloging-in-Publication DataBailer, Darice.

Why does it thunder and lightning? / by Darice Bailer.p. cm. — (Tell me why, tell me how)

Includes index.Summary: “Provides comprehensive information on the process of thunder and

lightning happening”—Provided by publisher.ISBN 978-0-7614-4825-9

1. Thunderstorms—Juvenile literature. 2. Lightning—Juvenile literature. I. Title. QC968.2.B35 2011551.55’4—dc222009033495

Photo Research by Candlepants Incorporated

Cover Photo: Paul Avis / Getty Images

The photographs in this book are used by permission and through the courtesy of:Getty Images: Photography by Steve Kelley aka “mudpig” , 1; Dennis Hallinan, 4, 13; Lyle Leduc, 5; Steve Allen , 8; Michael Hirsch,9; Samuel D. Barricklow, 15; Ryan McVay, 16; Harald Sund, 20; Gandee Vasan , 21; Phil Schermeister, 22; Erik Simonsen, 23. ArtResource, NY: Erich Lessing, 6. Photo Researchers Inc.: Sheila Terry, 7; Roger Harris, 12; Gary Hincks, 14. Alamy Images: B.A.E.Inc., 10; Scott Camazine, 11. Corbis: Martyn Goddard, 17. Marshall Cavendish Image Library: 19.

Editor: Joy BeanPublisher: Michelle BissonArt Director: Anahid HamparianSeries Designer: Alex Ferrari

Printed in Malaysia (T)

1 3 5 6 4 2


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


What is a Thunderstorm? – 5

What Makes Thunderstorm Clouds? – 9

How Does a Thunderstorm Begin? – 13

When Lightning Strikes – 17

What Causes Thunder? – 21

Activity – 25

Glossary – 28

Find Out More – 30

Index – 32

CONTENT

S


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


It is fun to play outside withyour friends in the rain. But ifyou hear the sound of thunder,you should all go inside asquickly as you can.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


5

What is a Thunderstorm?

On a dark gray day, you might see a flash of lightning. Abright light flickers in the sky and then BOOM! You hearthunder. The air cools and rain starts to fall. You feel it onyour nose and the top of your head.

Thunderstorms light up dark skies like fireworks. Athunderstorm has claps of thunder and lightning, and it canlast just a few minutes or many hours.

Lightning can sometimes lightup the whole sky so you cansee for miles.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


Every day, there are about 44,000 thunderstorms aroundthe world. Altogether these thunderstorms produce about fiftyflashes every second. Scientists estimate that lightning strikes

the earth about one milliontimes a day!

How lightning works was amystery for a very long time.Long ago, people thoughtangry gods threw lightningbolts down from the sky.Ancient Greeks believed thatZeus, the father of the gods,hurled thunderbolts to punishpeople. Africans believed thata giant bird-god beat his greatwings in the sky to makethunder. Native Americanscalled this bird a “thunderbird”and thought that it shotlightning out of its eyes.

Benjamin Franklin was afamous American and one of

This painting shows Zeus holding lightningbolts. In ancient times, people did not knowwhere lightning came from so they made upthe story of Zeus to explain why lightninghappened.

6


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


the fathers of our country.A scientist, Franklin thoughthe knew what causedlightning. And, one day in1752, Benjamin ran outside totest his idea. The sky was dark

with storm clouds as hegathered up a kite. He tieda key to the bottom of akite string. He also tied asilk ribbon to the end ofthe kite string and wrappedit around his fingers.Thunder cracked and it wasdangerous for Franklin tobe outside. But he wantedto fly his kite to see if hewas right.

What did Franklin wantto prove? And, why does itthunder and lightning?Keep reading to find out.

7

Benjamin Franklin tried to learn what causedlightning by experimenting with a kite and a key.

Now I Know!What is a thunderstorm?

A storm with claps of thunder and flashes of lightning.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


This cumulonimbus cloud means that rain,thunder, and lightning are likely on the way.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


9

What MakesThunderstorm Clouds?

A tall, dark thundercloud is called a cumulonimbus cloud.In Latin, cumulus means “heap” and nimbus means “rain”.But how do rain and clouds form?

On a warm day, the sun shines and heats the ground. Thisdries up water on the grass, sidewalk, and other surfaces. Allthis water escapes into the air. When the water on these

surfaces escapesinto the air, it isevaporating, orbecoming a gascalled water vapor.

Water can be aliquid, solid, or gasand it can changefrom one form tothe other. The wateryou drink is a

The process of rain starts through evaporation. When thesun warms up the air around this grass, the water on it willbegin to evaporate.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


10

liquid. But if you pour water into a tray and freeze it, thatliquid will turn into a solid—ice. And, if you boil water, youcan see it steam up and turn into water vapor. Because watervapor is a gas, it gets mixed inwith the rest of the air nearby.

If some of the air is a littlewarmer than the air around it,that air is lighter, too, and sorises. As warm air travels upinto the sky, it cools. The fartheryou travel away from thesurface of the earth, the colder itgets. And, when the rising aircools enough, the water vapormixed up in the air condensesand becomes a liquid again. Thewater vapor turns from a gasback into very small drops ofwater. Billions of tiny waterdrops form a cloud.

High up in the atmosphere,it is cold enough for water to

One of the easiest ways to see evaporationin action is watching water in a tea pot boil.The steam you see is water vapor.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


freeze. Tiny droplets of waterfreeze into ice crystals. Theseheavier crystals fall through thecloud and crash into more waterdroplets. When they do, thedrops of water freeze onto the ice crystals,making the ice bigger and forming soft hail. This soft hail helpscreate electrical forces that cause lightning!

11

Now I Know!What is a cloud made of?

Billions of tiny drops of water and ice crystals.

This photograph shows soft hail, as seen through a microscope. Soft hail helps trigger lightning.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


This computer illustration shows thestructure of an atom. Electrons are in blue,neutrons are in green, and protons are inred. Protons and neutrons make up thenucleus (center) of the atom. Electronsmove around the nucleus.


SEET DateAX: 8699851


1st

2nd3rd

4th

5th6th

Thunder_INT_FINAL_q7.qxd:Thunder 4/20/10 10:49 AM Page 12

Ice crystals and droplets and everything else in the world aremade of pieces that are so small you cannot see them. Theseinvisible pieces are called atoms.

Air, water, and even your own body are made of atoms.Atoms are so small that millions could fit on the eraser of

your pencil. Yet each atomis made up of even smallerparts called protons,electrons, and neutrons.

Protons and electronshave something calledelectric charge. Chargesare positive or negative,and charges that movemake an electric current.Electric currents makeelectricity so that

Everything in this photo is made is made up ofatoms—the rain, the umbrella, and even the child’sskin and hair.

13

How Does aThunderstorm Begin?


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


machines, televisions, and light bulbs can work. Electriccurrents get lightning going as well.

When wind whips upward through a tall cloud, small hailcollides with tinier pieces of ice inside a storm cloud. And, asthey bump into each other, some pieces of ice lose electrons

and some pieces ofice gain electrons.When this happens,they exchangeelectrical charges.The exchange ofcharges can create avery strong electricforce. The force canbe strong enough tocause lightning.

Down on theground, all we see isthe bottom of thedark storm clouds.The water and ice ina tall thunderstorm

14

Positive and negative charges are attracted to each other.In a thunderstorm, some of the lightning that begins in the cloud keeps moving toward the positive charge in the ground.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


15

act a bit like a bunch of tinymirrors. They reflect much ofthe sunlight toward the topand sides of the cloud. Thatmakes the top and sides ofclouds appear bright white. But itkeeps much of the sunlight from reaching the bottom of astorm cloud. This makes the bottom of the cloud look darkand gray. Those dark clouds mean a thunderstorm is coming.

Thunderheads are the towering clouds you see during thunderstorms. A singlethunderhead can cause a storm with lightning.

Now I Know!What do electric currents make?

Electricity. They get lightning going as well.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


When you drag yourfeet across a rug, suchas the one in thisphoto, you are pickingup lots of electrons.


SEET DateAX: 8699851


1st

2nd3rd

4th

5th6th

Thunder_INT_FINAL_q7.qxd:Thunder 4/20/10 10:49 AM Page 16

When Lightning Strikes

17

Have you ever dragged your shoes across a rug during thewinter? When you do this, you are picking up electrons! Therubbing action makes theelectrons stream up from therug and onto the soles of yourshoes. The rug loses electronsand you gain them. Electronsflow up your legs, through yourbody, and down to your fingers.

The electrons make yourfingers have a negative charge.And if you reach for a metaldoorknob with your fingers,you will soon find out that thenegative charge on your fingersmakes the metal doorknob havea positive charge.

This is what static electricity looks like. Thisis the moment of the spark you feel andsometimes see.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


Positive charges attract negative charges and negativecharges attract positive charges. When your negatively chargedfingers get closer to the positively charged doorknob, theelectric force between the two increases. When your fingergets close enough, then—zap! You create a tiny spark andfeel a shock!

Something like that happens inside the dark storm cloud.Wind stirs up the rain, hail, and ice crystals. The heavier hailfalls and collides with the smaller ice crystals and the twoexchange charge. As more and more soft hail forms and falls,the amount of charge increases and the electric force builds.

The electrically charged cloud makes the earth have apositive charge, the same way the negative charge on yourfinger makes a doorknob have a positive charge. A giantspark jumps through the air, and it looks like lightning is justcoming out of the bottom of a cloud. But electric sparks alsoskyrocket up from the ground and the sparks meet andconnect. Together they make one giant spark—lightning! Awhole lightning flash usually lasts less than one second.

Benjamin Franklin thought that thunderstorms containcharge and that lightning is a form of electricity. When hetook his key on a kite string out in that storm in 1752, he

18


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


19

proved that his thought wascorrect. The charge in theclouds above him made anelectric current flow throughthe kite string to the key.

Now I Know!What is lightning?

A giant spark of electricity made by a storm cloud.This illustration shows lightning striking a building. The large amount of negative charge in thecloud makes most of the earth beneath the cloud have a positive charge. The attraction growsbetween the cloud and the ground, and a spark jumps down from the cloud (image 2) andthen up from the building (image 3). When the two sparks meet, they make one giant sparkcalled lightning (image 4).


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


Lightning follows a crookedpath through the air. Mostlightning that you see is at least5 miles (8 kilometers) long.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


21

What Causes Thunder?

One of the scariest things about thunderstorms is the sound ofthunder. Thunder is one of the loudest sounds in the world.

And, the closer thelightning is to you, thelouder the thunder sounds.

A flash of lightning canbe very, very hot—greaterthan 50,000 degreesFahrenheit (28,000 degreesCelsius). The surface of thesun is only 11,000 °F(6,093 °C), which meanslightning is almost fivetimes hotter! A single flashof lightning is brighter than10 million light bulbs. Itlights up the entire sky!

Lightning usually strikes the tallest object in itspath because it is the easiest path for thelightning to take.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


But then you blink your eyes, and the lightning is gone.The electric current that flows through the sky heats the air sofast that the air explodes. The explosion causes a rumbling ora loud BOOM in the sky.

The light and thunder from lightning start moving towardus at the same time. But light moves nearly a million timesfaster than sound. Since light travels faster than sound, we seelightning first. Then we hear thunder.

22

When lightning strikes over 12 miles (19 km) away, such as out in the ocean, it isusually too far away to hear thunder.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


If lightning strikes the ground close to you, the thunderyou hear sounds like a loud bang. When lightning is a littlefarther away it makes thunder sounds like loud claps. When itis even further away the thunder sounds like rumbling. And iflightning strikes more than 12 miles (19 kilometers) away, it isusually too far to hear any thunder.

23

Lightning is dangerous because a very large electric current flows through it.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


24

Whenever you hearthunder, quickly goinside your house oranother building. Iflightning strikes you, itcan be deadly.

Not all lightning strikes the ground. Most lightning staysinside the clouds. Sometimes lightning leaps from one cloudto another. There is even lightning that shoots far out the topor side of a cloud.

Thunderstorms can bring heavy rain, hail, and flash floods.Their lightning can cause forest fires. Thunderstorms can bevery helpful as well. They bring rain to nourish plants and soiland to refill our rivers and oceans. And, we are still learningmore about them.

Now I Know!What is thunder?

It is the sound of lightning. Lightning heats up the air so

quickly that the air explodes.


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


Activity

You can hear a smaller version of thunder anytime youwant in your own home. All you need is a balloon anda woolen blanket, rug, or sweater—and a very quietroom! Blow up the balloon, rub it back and forth overthe woolen object for about thirty seconds, and listencarefully. Do you hear the little crackling sound of tinysparks between the balloon and the wool? Sparks makethat sound in the same way that lightning makesthunder!

This activity does not work as well on humid dayswhen the air has a lot of water vapor in it. It worksbest on days when the air is very dry.

When you rub the wool against the balloon, youare like the wind causing soft hail and ice crystals tobump against each other in a storm cloud. You arehelping electrons move. Electrons can move from onepiece of ice to another when the pieces of ice collide

25


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


inside a storm cloud, and they can leap from thesweater to the balloon when you rub the sweater andballoon together.

When sparks flow through the air between positiveand negative charge during a thunderstorm, the electriccurrent is so hot that the air explodes. When you rubthe balloon over the wool, they do not touch in someplaces, but are very close together. In places wherethey are close but not touching, very small sparks canflow through the air to carry some of the electrons thatthe balloon has captured back toward the sweater. Theelectric current that flows in the small sparks also heatsthe air and creates a small crackling sound. This crackleis a little like the loud thunder you hear during athunderstorm from the giant spark of lightning.

It takes thunder about five seconds to travel onemile. So the next time you see lightning in the sky,start counting the seconds. Then stop counting whenyou hear the clap of thunder. Next, divide that number

26


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


by five. The answer will tell you how many miles awaythe lightning is. For example, if you count to ten,lightning is two miles away. Sometimes you cannothear the thunder because the lightning is too far awayor the wind is too strong.

1) What happens if you count to twenty? Howmany miles away is the storm?

2) What happens if you count to thirty? How many miles away is the storm?

3) How far away is the storm if you count to thirty-five?

27


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


Glossary

atmosphere—The air.

atom—The tiny building blocks that make up everything in theuniverse.

condense—To change a gas, or water vapor, into liquid.

cumulonimbus cloud—A tall, dark cloud that is often a sign of athunderstorm. These clouds are also called thunderheads.

electric charge—Every atom is made up of protons, electrons andneutrons. In the middle of the atom is a nucleus which contains theprotons and neutrons. Electrons orbit around the nucleus. Protonshave a positive charge and electrons have a negative charge. Positivecharges are attracted to negative charges and negative charges areattracted to positive charges. Charge is what keeps electrons orbitingaround the nucleus.

electric current—The flow of electric charges from one place toanother. Current means “running” or “flowing”.

electric force—An invisible attraction between positive and negativeelectric charges. This force draws a negatively charged electrontoward a positively charged particle.

28


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


electricity—The movement of electrons or electric currents tocreate one kind of energy.

electrons—The parts of an atom that move around the center of anatom and have a negative charge of electrical energy.

invisible—Something that cannot be seen.

negative charge—An atom with extra electrons. When atoms gainelectrons, they are negatively charged.

neutrons—The parts inside the nucleus of an atom that have noelectric charge.

nucleus—The center of an atom which is made up of protons andneutrons.

positive charge—An atom that is missing electrons. When atomslose electrons, they have a positive charge.

protons—The positively charged parts of an atom.

spark—A flash of light made when electrons move suddenlythrough the air in a thin electric current. This electric current heatsthe air and makes it shine.

water vapor—The gas produced when water evaporates.

29


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


Find Out More

BOOKSHamilton, John. Lightning. Edina, MN: ABDO Publishing Company, 2006.

Hidalgo, Maria. Lightning. Mankato, MN: Creative Education, 2007.

Mayer, Cassie. Thunder and Lightning. Chicago: Heinemann Library, 2007.

McTavish, Douglas. Fried! When Lightning Strikes. London: A & C Black Publishers

Ltd., 2009.

Simon, Seymour. Lightning. New York: Collins, 2006.

30


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


WEBSITESA movie that shows how clouds and lighting form and how to be safe during a

thunderstorm.

www.kidsknowit.com/interactive-educational-movies/

free-online-movies.php?movie=Lightning

Cool facts about lightning along with pictures, safety tips and experiments

www.weatherwizkids.com/weather-lightning.htm

Facts and activities about weather from the National Oceanic and Atmospheric

Administration

www.education.noaa.gov/sweather.html

31


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


Index

32

Page numbers in boldface are illustrations.

Africans, beliefs about lightning, 6

air, 9, 10, 13, 22atoms, 12, 13, 13

clouds. See storm cloudscondensation, 10cumulonimbus clouds, 9

see also storm clouds

electric charges, 13, 14, 14, 17–18,19, 19

electric currents, 13–14, 19, 22, 23electricity, 13, 17, 18electrons, 12, 13, 14, 16, 17evaporation, 9, 9, 10

Franklin, Benjamin, 6–7, 7, 18–19

Greeks, beliefs about lightning, 6

hail, 11, 11, 14, 18, 24

ice/ice crystals, 10, 11, 13, 14, 18

lightning, 5, 5, 8, 14, 20, 23causes of, 11, 11, 13–14, 15study of, 6–7, 7, 18–19

lightning strikes, 6, 17–19, 19, 21,21–24, 22

liquid water, 9–10see also rain; water droplets

Native Americans, beliefs aboutlightning, 6

negative charges, 13, 14, 17–18,19

neutrons, 12, 13nucleus, 12

positive charges, 13, 14, 17–18, 19

protons, 12, 13

rain, 4, 5, 13, 18, 24

safety tips, 4, 23–24sparks, 17, 18, 19static electricity, 17storm clouds, 8, 9–11, 14, 14, 15,

15, 18, 19

thunder, 5, 8, 21–24thunderstorms, 5–7, 13–15, 14, 15,

21–24

water, forms of, 9–11water droplets, 10–11, 13, 14water vapor, 9, 10, 10

Zeus (Greek god), 6, 6


009 LKH DateAX: 8699851


1st

2nd3rd

4th

5th6th


why does it thunder and lightning? (tell me why, tell me how)

Documents