COMPUTERS IN THE CLASSROOM CT 243 Emery Roth email@example.com http://uhaweb.hartford.edu/eroth/
CHAPTER 2Communications, Networks, the Internet, and the World Wide Web
What are the two main categories of software… and how are they different? (1.13-1.14)
What are the “National Educational Technology Standards for Teachers” (NETS-T), and where do they come from? (1.19-1.20)
What is a “motherboard,” and what are its two main components? (1.08)
What are 5 components of a computer? …and give examples of each. (1.07-1.10)
What is, “the Internet,” and what are several ways it is useful for teachers? (1.17-1.18)
http://www.scsite.com/tdc2/ Click on “Chapter 1” From the menu on the left, select “Integration Corner,” then “chapter 1” Scroll to any level of personal interest & explore one resource
PROCESSING YOUR CLASSMATE SKETCHES • Gather by teams to regroup • Read at least 3 sketches. • Select group recorder (WP). • Process: • I really liked… • I learned to… • How do I…? • Publish???
Drawing Tablet • pressure-sensitive • designed to work with software applications that simulate real artists’ media
ASSIGNMENT posted on blackboard & web site Web site: http://uhaweb.hartford.edu/eroth/
CHAPTER 2Communications, Networks, the Internet, and the World Wide Web
Objectives • Define communications • Identify the basic components of a communications system • Describe how and why network computers are used in schools and school districts • Explain how the Internet works • Describe the World Wide Web portion of the Internet • Specify how Web documents are linked to one another • Explain the use of Web browser software • Explain how to use a Web search tool to find information • Identify several types of multimedia products available on the Web • Explain how Internet services such as e-mail, newsgroups, chat rooms, and instant messaging work • Describe how to connect to the Internet and the WWW
Communications Networks • Communications - refers to the transmission of data and information between two or more computers using a communications channel such as standard telephone lines • Communications network - is a collection of computers and other equipment organized to share data, information, hardware, and software • Communications software - programs that manage the transmissions of data between computers • Communications channel - is the path the data follows as the data is transmitted from the sending equipment to the receiving equipment in a communications system.
Communications Networks Continued • Transmission media - is the physical materials or other means used to establish a communications channel • Twisted-pair cable - consists of pairs of plastic-coated copper wire twisted together • Other examples (coaxial cable, fiber-optic cable, microwave transmission, communications satellites, and wireless transmissions
Communications Networks Continued • Digital signals - are individual electric pulses that a computer uses to represent data • Analog signals - continuous electrical wave used for telephone transmission and other devices • Modem - converts analog signals into digital signals • Network interface card (NIC) - connects computers directly to a school or business network without using a modem
Types of Networks • Local area networks (LAN) - is a communications network that covers a limited geographical area such as a school, an office, a building, or a group of buildings • Wireless LAN (WLAN) - uses no wires, instead it uses wireless media, such as radio waves. • Wide area networks - covers a large geographical region and used regular telephone cables, digital lines, microwaves, wireless systems, satellites, or othercombinations of communications channels. • Home networks - if you have multiple computers in your home or home office you can create your own network
History of the Internet • ARPANET - Advanced Research Projects Agency Network • allow scientists to share information • parts could function even if some of it went down • Established 1969 and by 1984 it had 1,000 hosts • In 1986 NSFnet joined together with ARPANET to serve as the backbone of the Internet • In 1995 NSF turned over responsibilities to major corporations • Internet2 - extremely high speed network that will develop and test advanced Internet technologies for research, teaching, and learning.
How the Internet works • Step 1. Data is divided into small pieces, called packets. • Step 2. Packets travel over the Internet via routers. • Step 3. At the destination, the packets are reassembled into the original message. • Packet switching • TCP/IP - transmission control protocol/Internet protocol - protocol used to define packet switching
ISP vs. OSP vs. WSP • Internet service provider (ISP) - allows you to connect to the internet for a fee. (ex. Netzero, ATT) • Online service provider (OSP) - allows you to connect to the internet and also provides other personalized options for a higher fee than an ISP • Wireless service provider (WSP) - allows users to connect to the internet without any wires. (ex. Palm)
Ways to Connect to the Internet • Dial-up access - you use your computer and a modem to dial in to the internet. (56k) • Cable modem - you use your existing tv cable and a cable modem (20-50 x faster) • Digital subscriber line - you use digital phone lines and dsl card. (25-150 x faster)
Internet Backbone • Step 1: Request a web page from your home computer • Step 2: Modem converts digital to analog • Step 3: Data travels through telephone lines to local ISP • Step 4: Data may travel through 1 or more routers • Step 5: Regional ISP uses lines, leased from a telephone company, to send data to a national ISP • Step 6: A national ISP routes data across the country to another national ISP • Step 7: Data moves from a national ISP to a local ISP to a server that contains the requested site • Step 8: The server requests the data and sends it back through the internet.
Internet Addresses • The Internet uses addresses the same way the post office does. Each computer has a specific numeric address. I.e. 18.104.22.168 • Domain name - the text version of a computer address • Domain abbreviations - .com, .edu, .gov, .mil, .net, .org, .k12 • Country abbreviations • Au - Australia; CA - Canada; UK - United Kingdom
World Wide Web • The Web - consists of electronic documents that have built in hyperlinks to other related documents • Hyperlinks - allow users to navigate quickly from one page to another • Web page - electronic document viewed on the Web that can contain audio, video, text, etc. • Web site - a collection of related web pages • Home page - starting point of a web site • URL - uniform resource locator • HTTP - hypertext transfer protocol
How a Web Page Works • Three types of hyperlinks exist • Target hyperlinks - links within the same page • Relative hyperlinks - link to another document on the same Internet computer (server) • Absolute hyperlinks - link to another document that could be located on a computer across the country • HTML - hypertext mark-up language - the code that defines what a website will look like
Web Browser Software • A web browser is a program that interprets HTML and displays Web pages and allows links to other pages • Mosaic - developed in 1993 by Marc Andreesen, a student at the University of Illinois • Netscape, Internet Explorer, AOL, Safari
Searching for Info. on the Web • Search tools - enable users to locate information found at Web sites all over the world • Search engine - a type of search tool that uses keywords • Subject directory - a type of tool that allows the user to navigate the directories and subdirectories
Multimedia on the Web • Multimedia is the combination of graphics, animation, audio, video, and virtual reality • Graphics - were the first media used to enhance text only sites • Animation - is the appearance of motions created by displaying a series of still images in rapid sequence • Audio - you can listen to prerecorded audio clips and live audio • Video - consists of full motion images that are played back at various speeds • Virtual reality - is the simulation of a real or imagined environment
E-mail • E-mail (electronic mail) - is the transmission of messages and files via a computer network • E-mail program - allows you to compose, view, send, and receive email • E-mail address - is a combination of a user name and a domain name
File Transfer Protocol • FTP - is an Internet standard that allows you to exchange files with other computers on the Internet. • Anonymous FTP - anyone can transfer files on this type of site.
Information Sharing via the Web • Newsgroup - is an online area in which users conduct written discussions about a particular subject • Mailing list - is a group of email addresses given a single name • Chat rooms - is a real-time typed conversation • Instant messaging - is real-time Internet communications service that notifies you when one or more people are online. • Netiquette - is the code of acceptable behavior while on the Internet
Interesting Sites • http://www.epals.com