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ppt

  1. 1. Lesson Four Searching Effectively on the World Wide Web
  2. 2. Introduction to Search Tools • Before starting this section, it is best to be familiar with terms related to the Internet and World Wide Web (WWW). • This lesson will focus on how to search the World Wide Web effectively and efficiently.
  3. 3. Introduction to Search Tools • Search Tools: – There are many type of search tools that you can use to locate information on the World Wide Web. – Various search tools are developed by different companies and have different search features and techniques. – They search different and overlapping parts of the WWW.
  4. 4. Introduction to Search Tools • NO single search tool searches ALL of the web sites (there are millions of web sites and more are added each and every day). • The search tools include: – Search engines – Web subject directories – Metasearch engines – the Invisible Web (also known as the "Deep Web")
  5. 5. Comparison of Different Search Tools: Search Engines • Definition: – Databases that contain millions and millions of pages. – Automated software ("robots" or "spiders") scan the Internet and collect information. – The search engine interface allows you to search for certain words or phrases found on Web pages. – In a search engine, you are searching for information within that search engine only, not the entire WWW.
  6. 6. Comparison of Different Search Tools: Search Engines • Advantages: – Search engines contain millions of web pages. – You retrieve results that match the word(s) that you are looking for. – Can be useful for searching for unique or specific topics.
  7. 7. Comparison of Different Search Tools: Search Engines • Disadvantages: – Depending on the search engine, you may get thousands or millions of results. – Many of the results may not be exactly what you are looking for, especially if you are using broad or common terms.
  8. 8. Comparison of Different Search Tools: Search Engines • Examples: – AltaVista (http://www.altavista.com) – Lycos (http://www.lycos.com) – Google (http://www.google.com)
  9. 9. Comparison of Different Search Tools: Web Subject Directories • Definition: – A collection of web sites gathered by the creators of the directory or submitted by publishers of web sites. – People evaluate and classify the web sites that are placed in the directory. – There may be short summaries that describe the web sites in the directory.
  10. 10. Comparison of Different Search Tools: Web Subject Directories • Advantages: – There may be a higher degree of accuracy using web directories for researching broad subjects or topics.
  11. 11. Comparison of Different Search Tools: Web Subject Directories • Disadvantages: – Usually fewer web sites than a search engine. – Web directories may not be as useful as search engines for researching specific or obscure topics.
  12. 12. Comparison of Different Search Tools: Web Subject Directories • Examples: – Yahoo! (http://www.yahoo.com)
  13. 13. Comparison of Different Search Tools: Metasearch Engines • Definition: – Similar to search engines but are used to search more than one search engine at a time. – Some Metasearch engines will also show you a small number of the "best" web sites from each search engine based on criteria established by the metasearch engine.
  14. 14. Comparison of Different Search Tools: Metasearch Engines • Advantages: – You can search several search engines at one time.
  15. 15. Comparison of Different Search Tools: Metasearch Engines • Disadvantages: – You may retrieve inappropriate Web sites depending on how each individual search engine interprets the search.
  16. 16. Comparison of Different Search Tools: Metasearch Engines • Examples: – Dogpile (http://www.dogpile.com)
  17. 17. Comparison of Different Search Tools: Invisible Web • Definition: – Web sites that are hidden from use by the general public. Also known as the Deep Web. – Includes specialized databases and directories.
  18. 18. Comparison of Different Search Tools: Invisible Web • Advantages: – Can be useful for specific topics or unique terms.
  19. 19. Comparison of Different Search Tools: Invisible Web • Disadvantages: – The Invisible Web will not be located by the use of conventional search engines and directories. You must know the URL or search using a search tool specifically created for searching parts of the Invisible Web.
  20. 20. Comparison of Different Search Tools: Invisible Web • Examples: – Complete Planet (http://www.completeplanet.com)
  21. 21. The Differences Between Search Tools • To demonstrate the differences between the four types of search tools, please conduct the following search using these four search tools: – Google (Search Engine) – Yahoo! (Web Directory) – Dogpile (Metasearch Engine) – Complete Planet (Invisible Web)
  22. 22. The Differences Between Search Tools • To start, open Google (http://www.google.com) in a new browser window. Perform a search for the psychologist Joyce Brothers. • How many results (hits) did you retrieve?
  23. 23. The Differences Between Search Tools • Now, search Yahoo! (http://www.yahoo.com). – Scroll down to the Web Site Directory section (sites organized by subject). – Click on Psychology (found under Social Sciences). – Click on Psychologists. – Click on Joyce Brothers. • How many results (hits) did you retrieve?
  24. 24. The Differences Between Search Tools • Now, search Dogpile (http://www.dogpile.com). "Go Fetch" Joyce Brothers! • How many results (hits) did you retrieve?
  25. 25. The Differences Between Search Tools • Finally, search Complete Planet (http://www.completeplanet.com). "Find databases relevant to" Joyce Brothers. • How many results (hits) did you retrieve?
  26. 26. The Differences Between Search Tools • As you can see from the searches above, you retrieve a variety of results using the different search tools. • Which search tool did you like the best? • The search engines may not be as precise ("on target") as some of the other search tools but retrieve a large number of results.
  27. 27. Before Starting a Search... • Before beginning a search, think about what you are looking for.
  28. 28. Effective Searching • Once you have decided on a search strategy, enter your search.
  29. 29. Limitations of the World Wide Web • It is important to realize that even the most effective Web searches will often turn up useless results (or no results at all). • Though the Web can be a wonderful search tool for current, "cutting-edge" information, there are limitations that can hinder a Web search. • What are some of these limitations?
  30. 30. A Limitation of the Web • Contrary to popular belief, everything cannot be found on the web. – There are millions and millions of documents written prior to the creation of the Internet. – Older, historical documents, in particular, may not have been digitalized and placed on the Web. – Most of what can be found on the Web is information that was developed after the creation and wide- spread use of the Web.
  31. 31. A Limitation of the Web • Not everything is free on the Web. • Some fee-based Web sites may require monthly or yearly subscriptions. • This includes many of the electronic databases. You (or your institution) pays for the privilege of accessing the information on those databases.
  32. 32. A Limitation of the Web • Web pages can be updated, redesigned, or removed. – Have you ever found a great Web page, just to find out that it can no longer be found two weeks later? – This is due to the fact that items on the Internet are not in a permanent format. – The Web address of a Web page can change. – The author of a Web page may decide to remove it from the Internet.
  33. 33. A Limitation of the Web • Anyone can publish web pages on the Internet. • All web pages are not "created equal." Becoming a web author is as easy as having access to the Internet and some web-building software. • Some of these "authors" may publish inaccurate or hurtful information. • It may be hard to verify the credibility of information on the WWW.
  34. 34. Using the Web for Research • Often, the Web may not be the best place to start your research. • You may instead choose to: – Review encyclopedias and reference books for background information. – Look at journal or magazine articles related to the topic. – Then... look for Web sites to supplement or update your information.
  35. 35. Evaluating a Web Site • As stated earlier, anyone can publish on the Web. • The author of a Web page may be opinionated or incorrect about the facts. • It is very important to look at a Web site thoroughly to make sure that it contains accurate and reliable information.
  36. 36. Take a Look at These Web Sites! • Below are the links to several Web sites. • Please take a look at these and determine whether the Web sites are credible and reliable sources of information.
  37. 37. Take a Look at These Web Sites! • Which of these sites are credible? – Dangers of Bread – National Aeronautics and Space Administration – Prehistoric Archaeology of the Aegean – Portland Online – Republic of Molossia – Smithsonian Institution
  38. 38. Take a Look at These Web Sites! • Dangers of Bread is NOT a valid Web site. • The National Aeronautics and Space Administration IS a valid Web site. • The Prehistoric Archaeology of the Aegean IS a valid Web site. • Portland Online IS a valid Web site. • The Republic of Molossia is NOT a valid Web site. • The Smithsonian Institution IS a valid Web site.
  39. 39. Take a Look at These Web Sites! How did you do? • Sometimes it is easy to know that a Web site is not credible, at other times it is very difficult.
  40. 40. For More Information About Searching Effectively on the World Wide Web... • Here are some Web sites that provide additional information. – Five Criteria for Evaluating Web Pages: (http://www.library.cornell.edu/olinuris/ref/research/webcrit.html) is a Web site developed by the Olin and Uris Libraries at Cornell University. – Noodle Tools: Search Strategies - Choose the Best Search for Your Information Need is an excellent source that describes the type of search tools that may work best for various topics. This Web site can be found at (http://www.noodletools.com/debbie/literacies/information/5locat e/adviceengine.html). – ICYouSee: A Guide to Critical Thinking About What You See on the Web contains useful advice on how to access and evaluate resources. This Web site is developed by the Ithaca College Library.(http://www.ithaca.edu/library/training/think.html).

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