Discovering Computers – Chapter Two

Using the Internet2010-2011

History of the InternetHow did the Internet originate?

Nextp. 69

Goal:To function if

part of network were disabled

Became functional

September 1969

ARPANET

Networking project by Pentagon’s Advanced

Research Projects Agency (ARPA)Goal:

To allow scientists at different

locations to share information

History of the InternetHow has the Internet grown? What do we call hosts today?

p. 69

TodayMore than 500 million host nodes

1984More than 1,000 host nodes

1969Four host nodes

Next

Who controls the Internet??

p. 70

World Wide Web Consortium (W3C) Oversees research, sets standards and guidelines

Mission is to contribute to the growth of the Web

Nearly 400 organizations around the world are members of the W3C

Next

No onec—cit is a public, cooperative, andindependent network

Several organizations set standards

Click to view Web Link,click Chapter 2, Click Web Linkfrom left navigation, then click W3Cbelow Chapter 2

High-speed connection

High-speed connection

Slow-speed technology

Slow-speed technology

How the Internet WorksHow can you connect to the Internet?

p. 70 Next

Dial-up accessmodem in your computer uses a

standard telephone line to connect to the Internet

Dial-up accessmodem in your computer uses a

standard telephone line to connect to the Internet

DSL, cable modem,FTTP, fixed wireless, wireless modem,

Wi-Fi, and satellite modems

DSL, cable modem,FTTP, fixed wireless, wireless modem,

Wi-Fi, and satellite modems

Connection is always on—whenever the computer

is running

Connection is always on—whenever the computer

is running

Connection must be established each time you log on.

Connection must be established each time you log on.

How the Internet WorksHow might data travel the Internet using acable modem connection?

p. 73 Fig. 2-3 Next

How the Internet WorksWhat is a domain name?

p. 73 - 74 Figs. 2-4 – 2-5 Next

Text version of Internet protocol (IP) address Number that uniquely identifies

each computer or device connected to Internet

The World Wide WebWhat is a Web browser?

p. 75 Next

Program that allows you to view Web pagesHow does a search engine work? Let’s REVIEW the Browsing the Web worksheet

together – What is Boolean logic? What engine provided the most results? Which engine do you prefer to use?

What is a home page? The first page of a website. It usually provides HYPERLINKS to other pages.

The World Wide WebWhat is a URL?

p. 76 - 77 Fig. 2-8 Next

Unique address for a Web page

A web server delivers the Web page to your computer.

URL – Uniform Resource Locator

Searching The World Wide Web

• PRESEARCH – get a definition that helps you choose keywords that will narrow your search results!

• OBJECTIVE – just the facts• SUBJECTIVE – opinions• OUTDATED/IRRELEVANT – old/not on topic• COMMERCIAL – business

The World Wide WebWhat are the guidelines for evaluating the value of

a Web site?

p. 84 Fig. 2-15 Next

Affiliation Audience Authority Content

Currency Design Objectivity

Technical and Visual Aspects

Does the page take a long time to load? Do any pictures or photographs on the page add to the information? Is the spelling correct on the page? Are there headings and subheadings on the page?

If so, are they helpful? Is the page signed by the author? Is the author's e-mail address included? Is there a date on the page that tells you when it was last updated?

If so, is it current? Is the format standard and readable with your browser? Is there an image map (large clickable graphic with hyperlinks) on the page? On supporting pages, is there a link back to the home page? Are the links clearly visible and annotated or explanatory? Are there photographs or sound files on the page?

If so, can you be sure that a picture or sound has not been edited? If you're not sure, should you accept the information as valid for your purpose?

Content Is the title of the page indicative of the content? Is the purpose of the page indicated on the home page? When was the document created? If there is no date, is the information current? Does up-to-date information matter for your purpose? Is the information useful for your purpose? Would it have been easier to get the information somewhere else? Would information somewhere else have been different?

Why or why not? Did the information lead you to other sources, both print and Web, that were useful? Is a bibliography of print sources included? Does the information appear biased? (One-sided, critical of opposing views, etc.) Does the information contradict something you found somewhere else? Do most of the pictures supplement the content of the page?

Authority Who created the page? What organization is the person affiliated with? Conduct a link: command in a search engine to see who links to this page. Can you tell if other experts in the field think this is a reputable page? Does the domain of the page (k12, edu, com, org, gov) influence your

evaluation? Are you positive the information is valid and authoritative?

What can you do to validate the information? Are you satisfied the information useful for your purpose?

If not, what can you do next? If you do a search on the creator of the page, do you find

additionalinformation that shows the Web page author is an expert in the field?

The World Wide WebWhat is a thumbnail?

p. 86 Fig. 2-18 Next

Small version of a larger graphicc—used to improve Web page display time Usually click

on thumbnail to display larger graphic

The World Wide WebWhat is animation?

p. 86 Next

Appearance of motion created bydisplaying a series of still imagesin sequence

The World Wide WebWhat is audio?

p. 86 - 87 Fig. 2-20 Next

Music, speech, or any other sound Individual compressed sound files that you download from the

Web to your computer Common Web audio file formats are AAC, AIFF, ASF, MP3, WAV,

WMA, RA, and QT Once downloaded, you can play (listen to) the contents of the files A podcast is recorded audio, usually an MP3 file, stored on a Web site

that can be downloaded to a computer or a portable media player

The World Wide WebWhat is streaming audio?

p. 86 Next

The process oftransferring audio

in a continuousand even flow

Enables you tolisten to music

as it downloadsto your computer

The World Wide WebWhat is video?

p. 88 Fig. 2-21 Next

Consists of full-motion images, most with sound, that are played back at various speeds

MPEG (Moving Pictures Experts Group) is popular video compressionstandard

Click to view Web Link,click Chapter 2, Click Web Linkfrom left navigation, then click YouTubebelow Chapter 2

The World Wide WebWhat is virtual reality (VR)?

p. 88 – 89 Fig. 2-22 Next

Use of computers to simulate real or imagined environment

Appears as a three dimensional (3-D) space Used for games and many

practical applications

The World Wide WebWhat are plug-ins?

p. 89 Fig. 2-23 Next

Programs that extend the capability of a browser

You can download many plug-ins at nocost from variousWeb sites

The World Wide WebWhat is Web publishing?

p. 89 - 90 Fig. 2-24 Next

Development and maintenance of Web pages

Business to business (B2B)Business providing goods and

services to other businesses

Consumer to consumer (C2C)One consumer sells directly to another

E-CommerceWhat is e-commerce?

p. 91 - 92 Fig. 2-25 Next

Business to consumer (B2C)Sale of goods to general public

Short for electronic commerce Business transaction that occurs

over the Internet

Click to view Web Link,click Chapter 2, Click Web Linkfrom left navigation, then click PayPalbelow Chapter 2