原版英语RAZ 教案The Internet.pdf

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1、The InternetA Reading AZ Level X Leveled BookWord Count:1,404 Visit www.readinga- for thousands of books and materials.www.readinga-The InternetWritten by Ned JensenLEVELED BOOK XThe InternetLevel X Leveled Book Learning AZWritten by Ned JensenAll rights reserved.www.readinga-Photo Credits:Front cov

2、er:Chad Baker/Ryan McVay/Digital Vision/Getty Images;back cover:iS Bisignani;title page:Cindy Charles/PhotoEdit;page 3:iS Slobodkin;page 4:iS F.Young;page 5:iS Monu;page 6:Don Farrall/Digital Vision/Getty Images;page 8:Pete Gardner/Digital Vision/Getty Images;page 10:Erik Reis/D;pages 11,12(main),17

3、(top),18(all),24:Jupiterimages Corporation;page 12(inset),21:iS;page 13:iS van Caspel;page 15:Creatas Photos;page 16:Elise Amendola/AP Images;page 17(bottom):iS Petrowski;page 19:Tetra Images/Corbis;page 20(top):Todd Wright/Blend Images/Corbis;page 20(bottom):Mitsu Yasukawa/Star Ledger/CorbisIllustr

4、ations:Pages 7,9,12,18(top),21:Randy GatesCorrelationLEVEL XS4040Fountas&PinnellReading RecoveryDRAThe InternetWritten by Ned Jensenwww.readinga-The Internet Level X3Introduction Can you imagine life without the Internet?Well,it might be hard to believe,but just a few decades ago,the Internet did no

5、t exist.The Internet has changed our lives and continues to change our lives,perhaps more than any other invention since the computer.The Internet has changed the way we communicate,gather information,shop,pay bills,and learn.4Table of ContentsIntroduction.4What Is the Internet?.5How Is Information

6、Sent?.6How Does the Internet Work?.10How Did the Internet Begin?.15How Is the Internet Used?.17Conclusion .20Explore More .21Glossary.22Index .24The Internet Level X5How Is Information Sent?Information packets sent over the Internet includes words,pictures,sound,and video.All of this information flo

7、ws through wire or fiber-optic cable.Wire cable is made from copper or other metals,while fiber-optic cable is made from bundles of very thin strands of glass or plastic.Internet information can also be sent wirelessly on radio waves.This is known as WiFi.A receiver within a WiFi network collects th

8、e information packets from radio waves.The receiver takes that collected information and sends it through the wire or fiber-optic cable that connects the receiver to the Internet.Fiber-optic cables are made to quickly carry huge amounts of information.6What Is the Internet?Simply said,the Internet i

9、s awesome.It is a system or network that connects millions of computers around the world.Any computer connected to the Internet can exchange packets of information with any other computer connected to the Internet.These connections allow information to pass from computer to computer at the speed of

10、light.Information packets sent from one computer can reach another computer on the other side of the world in just a few seconds.A series of ones and zeros make up the information packets computers send and receive.The Internet Level X78Fiber-optic cable has greater bandwidth than wire cable and,the

11、refore,can carry thousands of times more information than wire cables.As we become more dependent on the Internet for information,bandwidth becomes more important.Sound,pictures,and video all require more bandwidth than text.Therefore,information containing multimedia content needs greater bandwidth

12、 to flow through the Internet quickly.It takes two copper wires to carry one phone call.It takes two strands of fiber-optic cable to carry 24,000 phone calls.copper wirefiber-optic cableThe amount of information moving over the Internet at any given time depends on what is called bandwidth.The bandw

13、idth of a cable allows information to move like cars on a highway.The more lanes a highway has,the more cars that can travel on it.Greater bandwidth means that more information can travel through a cable.However,as with heavy traffic on a highway,when the amount of information traveling through a ca

14、ble increases,the speed at which it travels decreases.The Internet Level X910Bandwidth is a measure of the number of units of information prepared and sent by computers that can pass through the Internet per second.The smallest unit of information is called a bit.When eight bits are combined they be

15、come a byte.A single letter of text,such as the letter A,is one byte.Compare a typical typed sheet of paper,which has 2,000 bytes,with a short novel,which has one million bytes!Megabytes(1,000 kilobytes)and gigabytes(1,000 megabytes)are common measurements of computer storage capacity.02,0004,000Siz

16、e in kilobytes6,0008,00010,000Video8,500kMusic2,500kPicture500kText2k02,0004,000Size in kilobytes6,0008,00010,000Video8,500kMusic2,500kPicture500kText2kMath MinuteIf a kilobyte is 1,024 bytes,how many bytes are in a1-megabyte photograph?How Does the Internet Work?The backbone of the Internet is a pe

17、rmanently connected network of powerful computers to which other computers can connect.Individual computers connect to the Internet through a device called a modem,which decodes and codes digital information as it passes to and from your computer.You can access the Internet by using a modem and logg

18、ing in using a username and password.Internet access is usually purchased from an Internet Service Provider(ISP)for a monthly fee.Broadband users pay higher fees for high-speed Internet access using DSL or cable modems.Cable modemThe Internet Level X1112Once you have access,you are free to surf the

19、Internet.You can send information to,and receive information from,anyone else that is hooked up to the Internet.Lets say a friend tells you about a website where you can get information about tarantulas.You type in the website URL he gave you,including the file name,press“enter”(or“return”)on your k

20、eyboard or click the go button of your browser,and within seconds an article on tarantulas appears on your screen.So,how did this happen,you might ask.The Internet allows people to share information,including pictures.Here is a simple explanation of what happened.First,a browser,special Internet sof

21、tware for finding and looking at webpages,connected your computer to a server somewhere on the Internet.Next,the browser requested the website information.Then,the server retrieved the requested information and sent it back to your computer.Once the browser found the page you wanted,it made it possi

22、ble for you to view the page on your computer.1 webpage2 video file3 cell phone used to watch Internet video file123The Internet Level X13Every computer connected to the Internet,whether a server or a client,has an IP address (IP stands for Internet Protocol).Each IP address is a unique series of nu

23、mbers.The numbers are arranged in four sets with each set separated by a dot.For example,209.104.1.69 is the IP address for the computer that stores information for the website known as Raz-Kids,where students can read books their teacher has assigned.But since most people have a hard time rememberi

24、ng a series of numbers,computers are given domain names.The domain name for the Raz-Kids computer is raz-.14Lets take a closer look.All the computers that make up the Internet can be put into two groups:servers and clients.Servers are computers that provide a service,which is to give access to infor

25、mation.There are different kinds of servers.For example,to send or receive email,you will connect to an email server.To request information from a website,you will connect to a website server.The other computers on the Internet are computers like yours,called clients.Client computers dont provide a

26、service,but they do send and receive information.An information technology expert makes sure servers stay connected to the Internet.The Internet Level X1516How Did the Internet Begin?Most people think it all began back in the 1960s.The United States Department of Defense wanted to establish a depend

27、able network of communication in case of a disaster or war.The network that was created,called ARPAnet(Advanced Research Project Agency network),linked four computers to each other.By the 1980s,hundreds of computers were linked together.Soon,universities began building their own networks of computer

28、s so they could more easily share information.One of the largest networks for universities,called NSFnet(National Science Foundation network),came to be called the Internet.University students take advantage of free Internet access for communication and research.In the 1990s,a physicist named Tim Be

29、rners-Lee changed the Internet forever.Before Berners-Lee,a network would“talk”to its many computers,but could not share information with other networks.Each network spoke its own language and could not understand other networks,like people from different countries who spoke different languages.Bern

30、ers-Lee solved this problem by writing a common language that let computers in various networks“talk”to each other.Tim Berners-LeeThe Internet Level X1718How Is the Internet Used?One of the most frequent uses of the Internet is communication.Email replaces traditional postal letters,or“snail mail,”b

31、ecause it travels so much faster.A single message can be instantly sent to as many recipients as you want.If someone wants to respond to your email,they only have to click the reply button and then type out a message to send immediately back to you.You can also add attachments,such as photos,to your

32、 email.Answers to nearly any question can be found by searching the Internet.But with so much information available,how can you possibly find what you want?The answer is to use a search enginea tool that allows you to find the information you are looking for on the Internet.A search engine searches

33、the contents of millions of webpages at the same time.All you have to do is go to a search engine website and type in one or more search terms,or keywords.The fact that some monkeys eat fruit is information you could find on the Internet.The Internet Level X1920People also shop and pay bills on the

34、Internet.You can view pictures of products you may want to buy.You can listen to music,purchase it,and then listen to the music on your computer.You can also purchase airline and entertainment tickets on the Internet.Some shopping websites let you bid on the products you want to purchase just as you

35、 would at an auction.Internet shopping has become so popular that in 2004,Americans spent an estimated 65 billion to 70 billion dollars through the Internet.This girl listens through headphones to music on the Internet.Conclusion The Internet has allowed computers all over the world to connect to on

36、e worldwide network for sharing information.It has changed the way we do business,communicate,and buy goods and services.The Internet will be even more influential as more people around the world connect to it from homes,schools,businesses,and through wireless connections.The future of the Internet

37、is anyones guess,but one thing is certainhow the Internet is used today will change tomorrow.Police officers use the Internet through computers in their cars to find out information about suspects.Students use websites on the Internet to practice reading and other skills.The Internet Level XExplore

38、MoreOn the Internet1 In the address window of your browser,type .2 Type terms such as Internet,Tim Berners-Lee,or ARPAnet in the search window and click on“Google Search.”3 Read the colored links.Click on one that looks interesting.When you want to explore other links,click on the“back”button on you

39、r browser menu to return to the Google search page.4 Try other searches,using words from something you are studying in school,words from your favorite activities,or even names of your favorite animals or book characters.21Glossarybandwidth(n.)the maximum amount of information that can move on an Int

40、ernet cable(p.7)bit(n.)the smallest amount of information that can be stored on a computer or sent over the Internet(p.9)broadband(adj.)high-speed(p.10)browser(n.)special Internet software for finding and looking at webpages(p.11)byte(n.)a unit of information that can be stored on a computer and is

41、equal to one letter of the alphabet or one number(p.9)clients(n.)computers used by the general public to access all that the Internet provides(p.13)domain the easily remembered names(n.)identifications of websites that include extensions such or.edu(p.14)fiber-optic(adj.)a type of cable made from th

42、in strands of glass or plastic that can be used to carry signals(p.6)22The Internet Level XInternet(n.)a vast network of interconnected computers(p.4)IP address(n.)the number of a server or client computer(p.14)ISP(n.)stands for Internet Service Provider;companies that sell access to the Internet(p.

43、10)modem(n.)a device used to connect a computer to the Internet(p.10)multimedia(adj.)relating to programs or files for pictures,video,and sound (p.8)search a search tool used to locate engine(n.)information on the Internet (p.18)server(n.)a computer that provides access to information or services on

44、 the Internet(p.12)URL(n.)stands for Uniform Resource Locator;the entire address used to access a website on the Internet (p.11)WiFi(n.)wireless network for sending information over the Internet (p.6)2324Indexaccess,1013Berners-Lee,Tim,16,21browser,11,12,21cable,bandwidth,7,8 wire,6 fiber-optic,68 computer,client,13 domain name,14 IP address,14 language,16 modem,10 server,12 software,12connectivity,5,6,10,20Department of Defense,15email,13,17multimedia,8networks,ARPAnet,15 Internet,521 NSFnet,15 WiFi,6shopping,4,19universities,15website(-s),1114,18,19