Ppt Lesson 03


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Ppt Lesson 03

  1. 1. Unit 1—Computer Basics Lesson 3 The Internet and Research
  2. 2. Objectives <ul><li>List some reasons for searching the Internet. </li></ul><ul><li>Describe different search approaches. </li></ul><ul><li>Define a search engine. </li></ul><ul><li>Explain how search engines work. </li></ul><ul><li>Identify some of the more popular search engines. </li></ul>Computer Concepts BASICS -
  3. 3. Objectives (cont.) <ul><li>List some of the specialty search engines. </li></ul><ul><li>Describe some search tips and tricks. </li></ul><ul><li>Describe the subject directory search approach. </li></ul><ul><li>Describe the invisible Web. </li></ul>Computer Concepts BASICS -
  4. 4. Why Search the Internet? <ul><li>Reasons that people search the Internet </li></ul><ul><ul><li>Research for school assignments </li></ul></ul><ul><ul><li>Looking for medical and scientific information </li></ul></ul><ul><ul><li>Travel information and accommodations </li></ul></ul><ul><ul><li>Shopping for goods and services </li></ul></ul>Computer Concepts BASICS -
  5. 5. Internet Search Tools <ul><li>There are two basic types of Internet search tools: </li></ul><ul><ul><li>Search engines </li></ul></ul><ul><ul><ul><li>Perform searches based on keywords </li></ul></ul></ul><ul><ul><li>Subject directories </li></ul></ul><ul><ul><ul><li>Search by specialized topics </li></ul></ul></ul><ul><li>What is the difference between them? </li></ul><ul><ul><li>Search engines are automated. </li></ul></ul><ul><ul><li>Directories are assembled by people. </li></ul></ul>Computer Concepts BASICS -
  6. 6. What Is a Search Engine? <ul><li>Search engines are programs that allow you to search for information. </li></ul><ul><li>There are hundreds of search engines on the Internet. </li></ul><ul><li>Search engines allow keyword searching. </li></ul><ul><ul><li>Some support concept-based searching. </li></ul></ul><ul><ul><li>Some support stemming . </li></ul></ul><ul><li>The list of results returned from your search are called hits . </li></ul>Computer Concepts BASICS -
  7. 7. Search Engine Components <ul><li>Search engines usually have three main components. </li></ul><ul><ul><li>The search engine program that does the search of its database </li></ul></ul><ul><ul><li>A spider or crawler that looks for the information in the database </li></ul></ul><ul><ul><li>The index that is built from information returned by the spider </li></ul></ul>Computer Concepts BASICS -
  8. 8. Keyword Searches <ul><li>Keyword searches look for specific words within a Web page. </li></ul><ul><li>Many search engines use meta tags to build their search index. </li></ul><ul><ul><li>Meta tags are HTML tags in a Web page that do not display, but can be used to define page content. </li></ul></ul>Computer Concepts BASICS -
  9. 9. Keyword Searches (cont.) <ul><li>Search engines also use significant words to build their index. </li></ul><ul><ul><li>Significant words may be words mentioned near the beginning of a page or repeated frequently throughout the page. </li></ul></ul><ul><li>Some search engines claim to index all words in a Web page. </li></ul>Computer Concepts BASICS -
  10. 10. Keyword Search Steps <ul><li>To search using keywords: </li></ul><ul><ul><li>Connect to the Internet and go to a search engine site. </li></ul></ul><ul><ul><li>Enter your keywords in the search box. </li></ul></ul><ul><ul><ul><li>Many search engines allow you to enter a phrase or sentence. </li></ul></ul></ul><ul><ul><li>The search engine examines its internal database index looking for your words. </li></ul></ul>Computer Concepts BASICS -
  11. 11. Keyword Search Steps (cont.) <ul><li>To search using keywords (cont.): </li></ul><ul><ul><li>The search engine returns a list of hyperlinks (hits) to Web sites containing your words. </li></ul></ul><ul><ul><li>Click a hyperlink to go to that site. </li></ul></ul><ul><li>If you get no hits on your search, revise your keywords and try again. </li></ul>Computer Concepts BASICS -
  12. 12. Major Search Engines <ul><li>Although there are hundreds, these are some of the more well known search engines: </li></ul><ul><ul><li>Yahoo at yahoo.com </li></ul></ul><ul><ul><li>Microsoft at msn.com </li></ul></ul><ul><ul><li>America Online at aol.com </li></ul></ul><ul><ul><li>Ask Jeeves at ask.com </li></ul></ul><ul><ul><li>Netscape at netscape.com </li></ul></ul>Computer Concepts BASICS -
  13. 13. Specialty Search Engines <ul><li>These also are called category-oriented search engines. </li></ul><ul><li>They are commonly used for </li></ul><ul><ul><li>Locating people </li></ul></ul><ul><ul><li>Finding shareware and freeware </li></ul></ul><ul><ul><li>Shopping </li></ul></ul><ul><ul><li>Sports-related information </li></ul></ul><ul><ul><li>Career planning </li></ul></ul>Computer Concepts BASICS -
  14. 14. A Specialty Search Web Site Computer Concepts BASICS - This figure shows the Beaucoup Web site page. Note the various categories of information available. Clicking a sub-category will bring up a new page of categories until you find the exact topic you are searching for.
  15. 15. Tools and Techniques for Searching <ul><li>Some commonly used techniques </li></ul><ul><ul><li>Phrase searching </li></ul></ul><ul><ul><li>Search engine math </li></ul></ul><ul><ul><li>Boolean searching </li></ul></ul><ul><ul><li>Wildcard searching </li></ul></ul><ul><ul><li>Title searching </li></ul></ul>Computer Concepts BASICS -
  16. 16. Phrase Searching <ul><li>This is used to search for words that must appear next to each other. </li></ul><ul><li>Phrases must be enclosed in double quotation marks. </li></ul><ul><ul><li>“ Books on the Civil War” </li></ul></ul><ul><li>Only sites with the exact phrase will be returned as hits. </li></ul><ul><li>You should capitalize proper nouns. </li></ul>Computer Concepts BASICS -
  17. 17. Search Engine Math <ul><li>Use math symbols to enter formulas or to filter out unwanted listings. </li></ul><ul><ul><li>A plus sign ( + ) before a word means it must appear. </li></ul></ul><ul><ul><li>A minus sign ( - ) before a word means it should not appear. </li></ul></ul>Computer Concepts BASICS -
  18. 18. Search Engine Math (cont.) <ul><li>Examples of search engine math </li></ul><ul><ul><li>To search for sites that contain both cookies and recipes, enter </li></ul></ul><ul><ul><ul><li>+cookies+recipes </li></ul></ul></ul><ul><ul><li>To exclude sites that have coconut cookie recipes, enter </li></ul></ul><ul><ul><ul><li>+cookies+recipes-coconut </li></ul></ul></ul>Computer Concepts BASICS -
  19. 19. Boolean Searching <ul><li>Boolean logic is similar to search engine math, but is more powerful. </li></ul><ul><li>Boolean logic consists of three operators: </li></ul><ul><ul><li>AND: Search for sites that include Word A AND Word B. </li></ul></ul><ul><ul><li>NOT: Search for sites the include Word A but NOT Word B. </li></ul></ul><ul><ul><li>OR: Search for sites that include Word A OR Word B. </li></ul></ul>Computer Concepts BASICS -
  20. 20. Wildcard Searching <ul><li>Wildcard searching allows you to search for words for which you may not know the spelling or to search for plurals or variations of a word. </li></ul><ul><li>The wildcard character ( * ) lets you search for any word that has the characters before or after the wildcard character. </li></ul>Computer Concepts BASICS -
  21. 21. Wildcard Searching (cont.) <ul><li>Wildcard search example </li></ul><ul><ul><li>To search for the element potassium without knowing how it is spelled, enter </li></ul></ul><ul><ul><ul><li>PO* or po*ium </li></ul></ul></ul><ul><li>Not all search engines support wildcard searches. </li></ul>Computer Concepts BASICS -
  22. 22. Related Searching <ul><li>Some search engines have a related search feature. </li></ul><ul><li>The search engine will return hits based on your search criteria and may also display a list of other sites that have information related to your search criteria. </li></ul><ul><li>This can greatly improve the odds of finding the information that you want. </li></ul><ul><li>Note: Some sites call this feature similar pages or more pages like this . </li></ul>Computer Concepts BASICS -
  23. 23. Subject Directory Searching <ul><li>Subject experts personally examine Web sites and add the URL to a search engine if it meets standards. </li></ul><ul><li>Subject directories are organized by subject categories. </li></ul>Computer Concepts BASICS -
  24. 24. Subject Directory Searching (cont.) <ul><li>Subject categories </li></ul><ul><ul><li>Each category has a collection of links to Internet resources. </li></ul></ul><ul><ul><li>The resources are arranged by subject and displayed in menus. </li></ul></ul><ul><li>You start at the top of a category and drill down from a generic start to a specific topic. </li></ul>Computer Concepts BASICS -
  25. 25. A Subject Directory Site Computer Concepts BASICS - This figure shows the Yahoo Subject Web site.
  26. 26. Advantages of Subject Directory Searches <ul><li>They usually provide a more guided approach than keyword searches. </li></ul><ul><li>They are easy to use. </li></ul><ul><li>You are not searching the entire Web. </li></ul><ul><li>The linked sites have been handpicked and evaluated. </li></ul><ul><li>Most links include a description. </li></ul><ul><li>They produce better quality hits on searches for common items. </li></ul>Computer Concepts BASICS -
  27. 27. Popular Subject Search Sites <ul><li>About: about.com </li></ul><ul><li>The Librarians Index: www.lii.com </li></ul><ul><li>Yahoo: www.yahoo.com </li></ul><ul><li>Galaxy: www.galaxy.com </li></ul>Computer Concepts BASICS -
  28. 28. Advanced Search Forms Computer Concepts BASICS - This figure shows the advanced search form for the AltaVista Web site. It is designed to assist you in performing advanced searches by providing text box options.
  29. 29. The Invisible Web <ul><li>Also known as the “deep Web” </li></ul><ul><ul><li>Indexes searchable databases </li></ul></ul><ul><li>Resources </li></ul><ul><ul><li>www.completeplanet.com </li></ul></ul><ul><ul><li>www.profusion.com </li></ul></ul>Computer Concepts BASICS -
  30. 30. Summary <ul><li>Search engines and directories are two basic tools that you can use to find information on the Web. </li></ul><ul><li>People assemble directories; search engines are automated. </li></ul><ul><li>A search engine is a software program. </li></ul><ul><li>Most search engines support keyword searches. </li></ul>Computer Concepts BASICS -
  31. 31. Summary (cont.) <ul><li>Concept-based searching occurs when the search engine returns hits that relate to keywords. </li></ul><ul><li>Stemming relates to the search engine’s capability to find variations of a word. </li></ul><ul><li>Meta tags are special tags embedded in a Web page; many search engines use the tags to create their indexes. </li></ul>Computer Concepts BASICS -
  32. 32. Summary (cont.) <ul><li>Keywords describe the information you are trying to locate. </li></ul><ul><li>Search engines contain a database of organized information. </li></ul><ul><li>Some search engines use natural language. </li></ul><ul><li>A search engine has three main parts: the search engine software, a spider that searches for keywords, and an index. </li></ul>Computer Concepts BASICS -
  33. 33. Summary (cont.) <ul><li>Stop words, such as www , but , and or , are not indexed by many search engines. </li></ul><ul><li>A search engine uses an algorithm to index Web sites. </li></ul><ul><li>Specialized search engines focus on a particular topic. </li></ul><ul><li>Multimedia search engines focus on video, animation, graphics, and music. </li></ul>Computer Concepts BASICS -
  34. 34. Summary (cont.) <ul><li>Subject directories are organized by subject categories. </li></ul><ul><li>Subject experts check the Web sites that are part of a subject directory’s database. </li></ul><ul><li>Use double quotation marks around a set of words for phrase searching. </li></ul><ul><li>Use the plus and minus signs for inclusion and exclusion of words within a search. </li></ul>Computer Concepts BASICS -
  35. 35. Summary (cont.) <ul><li>Boolean searching uses the three logical operators OR, AND, and NOT. </li></ul><ul><li>The * symbol is used for wildcard searching. </li></ul><ul><li>No single organization indexes the entire Internet. </li></ul>Computer Concepts BASICS -