Lesson 12

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Lesson 12 The Internet and Research
Unit 3 Advanced Computer Concepts

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Objectives

• List some reasons for searching the Internet.
• Describe different search approaches.
• Define a search engine.
• Explain how search engines work.
• Describe how search engines search.

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Objectives (continued)

• Identify some of the more popular search engines.
• List some of the specialty search engines.
• Describe the subject directory search approach.
• Describe some search tips and tricks.

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Internet Search Tools

• There are two basic types of Internet search
  tools
• Search engines
• Perform searches based on keywords
• Subject directories
• Search by specialized topics
• What is the difference between them?
• Search engines are automated.
• Directories are assembled by people.

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Why Search the Internet?

• Some reasons that people search the Internet
  include
• Research for school assignments.
• Looking for medical and scientific information.
• Travel information and accommodations.
• Shopping for goods and services.

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What Is a Search Engine?

• Search engines are programs that allow you to
  search for information.
• There are hundreds of search engines on the
  Internet.
• Search engines allow keyword searching.
• Some support concept-based searching.
• Some support stemming.
• The list of results returned from your search are
  called hits.

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Keyword Searches

• Keyword searches look for specific words within a
  Web page.
• Many search engines use meta tags to build their
  search index.
• Meta tags are HTML tags in a Web page that do not
  display, but can be used to define page content.
• Search engines also use significant words to
  build their index.
• Significant words may be words mentioned near the
  beginning of a page or repeated frequently
  throughout the page.
• Some search engines claim to index all words in a
  Web page.

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Keyword Search Steps

• To search using keywords
• Connect to the Internet and go to a search engine
  site.
• Enter your keywords in the search box.
• Many search engines allow you to enter a phrase
  or a sentence.
• The search engine examines its internal database
  index looking for your words.
• The search engine returns a list of hyperlinks
  (hits) to Web sites containing your words.
• Click a hyperlink to go to that site.
• If you get no hits on your search, revise your
  keywords and try again.

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Search Engine Components

• Search Engines usually have three main
  components
• The search engine program that does the search of
  its database.
• A spider or crawler that looks for the
  information in the database.
• The index which is built from information
  returned by the spider.

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Check the Relevance Rating
Search engines usually provide a relevance rating
percentage for each hit.
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Major Search Engines

• Although there are hundreds, these are some of
  the most well known
• Lycos www.lycos.com
• Yahoo! www.yahoo.com
• AltaVista www.altavista.com
• Google www.google.com
• Infoseek www.infoseek.com
• Excite www.excite.com
• WebCrawler www.webcrawler.com

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Specialty Search Engines

• These are also called category-oriented search
  engines.
• They are commonly used for
• Locating people.
• Finding shareware and freeware.
• Shopping.
• Sports-related information.
• Career planning.

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A Specialty Search Web Site
This figure shows the Beaucoup Web site page.
Note the various categories of informa-tion
available.
Clicking a sub-category will bring up a new page
of categories until you find the exact topic you
are searching for.
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Subject Directory Searching

• Subject experts personally examine Web sites and
  add the URL to a search engine if it meets
  standards.
• Subject directories are organized by subject
  categories.
• Each category has a collection of links to
  Internet resources.
• The resources are arranged by subject and
  displayed in menus.
• You start at the top of a category and drill down
  from a generic start to a specific topic.

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A Subject Directory Site
This figure shows the Encyclopedia Britan-nica
Web site. Note the subject list on the left side
of the screen.
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Advantages of Subject Directory Searches

• They usually provide a more guided approach than
  keyword searches.
• They are easy to use.
• You are not searching the entire Web.
• The linked sites have been handpicked and
  evaluated.
• Most links include a description.
• They produce better quality hits on searches for
  common items.

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Popular Subject Search Sites

• Encyclopedia Britannica www.britannica.com
• The Librarians Index www.lii.com
• Yahoo www.yahoo.com
• Galaxy www.galaxy.com

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Tools and Techniques for Searching

• Some commonly used techniques are
• Phrase searching
• Search engine math
• Boolean searching
• Wildcard searching
• Title searching

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Phrase Searching

• This is used to search for words that must appear
  next to each other.
• Phrases must be enclosed in double quotation
  marks.
• For example books on the Civil War
• Only sites with the exact phrase will be returned
  as hits.
• You should capitalize proper nouns.

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Search Engine Math

• Use math symbols to enter formulas or to filter
  out unwanted listings.
• A plus sign () before a word means it must
  appear.
• A minus sign (-) before a word means it should
  not appear. For example,
• to search for sites that contain both cookies and
  recipes, enter
• cookiesrecipes
• to exclude sites that have coconut cookie
  recipes, enter
• cookiesrecipes-coconut

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Boolean Searching

• Boolean logic is similar to search engine math,
  but is more powerful.
• Boolean logic consists of three operators
• AND Search for sites that include Word A AND
  Word B.
• NOT Search for sites the include Word A but NOT
  Word B.
• OR Search for sites that include Word A OR Word
  B.

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Advanced Search Forms
This figure shows the advanced search form for
the HotBot Web site. It is designed to assist you
in performing math and Boolean logic-oriented
searches by setting text box options.
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Wildcard Searching

• Wildcard searching allows you to search for words
  that you may not know the spelling of or to
  search for plurals or variations of a word.
• The wildcard character () lets you search for
  any word that has the characters before or after
  the wildcard character.
• For example, to search for the element potassium
  without knowing how it is spelled, enter
• PO or poium
• Not all search engines support wildcard searches.

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Title Searching

• Web pages usually contain an HTML ltTitlegt tag.
• The text in that tag is displayed in a Web
  browser title bar when the page is loaded.
• Several (but not all) search engines allow you to
  search for specific Web page titles.

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Related Searching

• Some search engines have a related search
  feature.
• 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.
• This can greatly improve the odds of finding the
  information that you want.
• Note Some sites call this feature similar pages
  or more pages like this.

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Summary

• Two basic tools you can use for finding
  information are search engines and directories.
• People assemble directories, and search engines
  are automated.
• A search engine is a software program.
• Most search engines support keyword searches.
• Concept-based searching occurs when the search
  engine returns hits that relate to keywords.

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Summary (continued)

• Stemming relates to the search engine finding
  variations of the word.
• Meta tags are special tags embedded in a Web
  page many search engines use the tags to create
  their index.
• Keywords describe the information that you are
  trying to locate.
• Search engines contain a database of organized
  information.

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Summary (continued)

• Some search engines use natural language.
• A search engine has three main parts the search
  engine software, a robot that searches for
  keywords, and an index.
• Stop words such as www, but, or, and so forth are
  not indexed by many search engines.
• The URL is the same as the Web site address.
• A relevance rating percentage indicates how close
  a site matches keywords.

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Summary (continued)

• A search engine uses an algorithm to index Web
  sites.
• Specialized search engines focus on a particular
  topic.
• Multimedia search engines focus on video,
  animation, graphics, and music.
• Subject directories are organized by subject
  categories.
• Subject experts check the Web sites that are part
  of the subject directorys database.

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Summary (continued)

• Use double quotation marks around a set of words
  for phrase searching.
• Use the plus and minus sign for inclusion and
  exclusion of words with a search.
• Boolean searches use the three logical operators
  OR, AND, and NOT.
• The symbol is used for wildcard searching.

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Summary (continued)

• Some search engines support title searching.
• A related search is a preprogrammed question
  suggested by the search engine.
• No single organization indexes the entire
  Internet.