How to Find World Wide Web Sites
Module W12c
Contents
Objectives- Ways to Find Information on the Web
- Web Catalogs and Directories
- Tools for Finding what you Want
- What is Being Searched For?
- Useful Web Search Engines
- Bringing Order out of Chaos: Search Tips and Tricks
- How to Search for Information using Boolean Logic
In a Web browser, youmay click this separator wherever it appears to return to the Contentsof this document.
Objectives
- Explain the difference between browsing and directed searching of the Web.
- Discuss the usefulness of the more commonly used catalogs or directoriesof the Web.
- Discuss the usefulness of the more commonly used search engines on theWeb.
- Explain the Boolean operations used in searching
- Discuss ways in which search interfaces handle specifiers, including:
- Adjacent words
- Quoted phrases
- Boolean operators
- Capital letters
- Explain degrees of success in search results
- Discuss techniques for dealing with unsuccessful searches
Audience:
People who want to know how to find sites of interest on the Web. Needto know the basics of Web browser operation. (Module W01c"World Wide Web Concepts" is designed to provide the needed background.)
Ways to Find Information on the Web
Browsing
- Browsing is following links in documents until you find something useful
- Useful if:
- you have a general subject area to search for
- you don't have specific keywords to look for
- you have a fairly useful starting place
- Best tool: your own bookmark file (see module W08c "SavingWeb Addresses")
- Some good starting places are listed in this module
Searching
- Searching makes use of database "search engines" that find informationfor you
- Useful if you have a specific set of keywords to look for
- Several useful tools are available... stay tunedto this module!
Web Catalogs and Directories: Launch Pads for Browsing
Washtenaw Community College Resources
WCC's Learning Resources Center offers several on-line resources for trackingdown information:You can search the library on-line, find books you need, and then pickup the books quickly while on campus.If you are using any Washtenaw Community College campus computer (not fromhome or office!) you can access a large number of databases that wouldotherwise be quite expensive to use.
General Directories
Sponsored by The Library of Michigan and the University of Michigan, UniversityLibrary. It is funded, in part, with Library Services and Technology Act(LSTA) funds administered by the Library of Michigan.- Slant: serious research
- Michigan residents can access commercial databases with information fromcurrent magazines
- Top-level Categories: Business, Economics & Labor, Libraries& Information Science, Children & Young Adults, Michigan,Education, News, Media & Periodicals, Government, Politics &Law, Recreation & Leisure, Health Information Resources, ReferenceDesk, Humanities & the Arts, Science & the Environment, The Internet& Computers, Social Issues & Social Services
- Slant: personal interest
- Available by clicking a button in Netscape
- Managed by Yahoo
- Top-level subject categories: Art, Business and Economy, Computers andInternet, Education, Entertainment, Government, Health, News, Recreation,Reference, Regional, Science, Social Science, Society and Culture
- Slant: serious research
- Run by World Wide Web Consortium
- Has a very detailed top-level subject list - too long to put in here!
- Slant: Research both personal and serious
- Each sub-category has a sub-editor who keeps the links updated and respondsto questions
- Quite thorough
http://home.miningco.com/
Specialized Directories
Business
- U.S.Department Of Commerce Information Services via World Wide Web
- The U.S. Commerce Department offers a lot of information on its own, andincludes links to other sites as well. http://www.doc.gov/
- QuickenFinancial Network
- Quicken provides home finance software and services, but this site alsocontains useful links to business and investment information. http://www.quicken.com/
- WallStreet Journal:
- Information and links are available to non-subscribers, but of course theywould like you to subscribe to their on-line edition! http://www.wsj.com/
Medicine
Universityof Michigan Medical Center Home Page:From this site you can get to a great deal of medical information at differentlocations. http://www.med.umich.edu/National Library of MedicineGives access to lots of research journal abstracts, as well as news aboutdevelopments in medicine. http://www.nlm.nih.gov/Science and Technology
NASA Home PageNASA's home page offers links to many other sites related to earth scienceand space science.http://www.nasa.gov/- CIESINHome Page:
- Center for International Earth Science Information Network. http://www.ciesin.org/
United States - Government and People
Library of Congress- Slant: books; records of government, especially Congress
- Library of Congress (LC) is the largest library in the world.
- The Library of Congress offers a wide variety of online databases and Internetresources.
- In addition, LC provides an easy-to-use gateway for searching other institutions'online catalogs and extensive links to resources on the Internet.
FedWorld- Slant: Government information
- Run by the U.S. Department of Commerce
- Gateway to U.S. Federal Government information on the Web.
- You can browse through lists of Web sites, select from lists of on-linedatabases, or use keyword search to find the Federal Web site or databaseyou need.
GOVBOT - Government search engineUSDemography:
Slant: find information about U.S. populations and preferencesSponsored by CIESIN: the Consortium for International Earth Science NetworkingCIESIN's link page to many types of information about the people of theUnited States. http://www.ciesin.org/datasets/us-demog/us-demog-home.htmlKeyword Searching on the Web
Most people, most of the time, try to find what they want on the Web bygoing to a "search engine", typing in a key word or phrase, and waitingto see what "hits" the engine finds. This is convenient, and the resultscan be spectacular sometimes, with millions of "hits" on the Web...buthow do you know which ones are truly worth looking at? Critical thinkingis essential when using this type of search!Tools for finding what you want
Many search engines have tools to help you specify what you want. Two suchtools are the use of "quotation marks" and the use of Capital Letters.To find out which engines use these, check their help documentation.- "Quotation marks" can be used in some engines to group words orphrases together. For example, if you use
white house
most search engines will look for the two words anywhere in the titleor key words section, in any order. With some, however, if you use thesearch string in quotes,
"white house"
the two words must appear together, in order. This can make your searchmore precise.- Capital Letters are treated by some engines are exactly the sameat lower-case letters. Others have a different rule: they treat lower-caseletters as matching both lower- and upper-case (capital) letters, whilecapitals match only capitals. In these,
white house
would match white house, White House, white House, White house,WHITE HOUSE, or wHiTe HoUsE. But
White House
would not match white or house.
What is Being Searched? What is being Returned?
Search engines can look at many things on a Web page. What they look atmay determine whether they will find what you need. Check each engine'son-line help for details. Here are some things that might be searched:- Web page titles - these are not normally shown when you view an HTML document,but are entered by the author specifically for search engines to find
- The first X lines of a document. Usually this includes the title you see,but it does not include words contained in graphic files.
- The entire text of the page. This is rare, since it is very slow. However,there may be some engines that do it.
- Other types of information besides Web pages. Such as...
- Gopher menus
- Texts referred to by Gopher or Web links
- Names of files available by FTP
- Newsgroup postings
The search engine you choose will have its own list of documents to search.Some allow you to change this list, but for most it's fixed. Choose theengine that searches what you need to find.Another important difference between search engines is, what do theyshow you when they get a "hit"? It could be...
- Title only - these let you see a lot of "hits" on one screen.
- The first X lines of the document - these can't show as many hits, butgive you more information about each one.
Again, you'll want to choose an engine that gives you what you find mostconvenient.
Usefulness of Web Search Engines
Several Web sites offer useful reviews of search enginces. Here are linksto a few of them:Bringing Order out of Chaos: Search Tips and Tricks
Degrees of Success
Perfect success is when the search engine finds all the items that arerelevant to what you want, and none of the items that aren't. Perfect successis almost non-existent, because computers don't really understand humans.(Humans sometimes have a hard time understanding each other, too, I'venoticed...!)What is failure?
- Complete failure is when you get no "hits" at all.
- You can also fail if the engine returns some "hits" to you, but none ofthem really has anything to do with what you want to find.
- Suppose you get hundreds or thousands of "hits"? That's no good either- it means you spend hours browsing when you wanted a quick search!
How successful is success?
Many search engines use a system for rating "hits" that lets you tell roughlyhow good the hit is. Generally, hits are shown to you in the order of highestto lowest rating.How does a hit get rated?
- Having all the words you put in your search string makes for high ratings;
- Having the words in the search string appear right next to each other,in order, makes the rating even higher;
- If the words aren't together, but are still pretty close, the rating willbe fairly high;
- The farther apart search words are, and the fewer there are of them, thelower the rating will be.
General Tips and Tricks
- Take time to read the on-line help for several engines.
- Don't be afraid to try several ways to do a search. You don't have to getit right the first time, and sometimes you learn more by trying than byreading about it!
- Bookmark the engines you find most helpful.. If you know how, add informationabout what they search, how they search, and what they return to you.
- If a search doesn't work on one engine, try another. It may search a differentselection of items, or use a different search technique.
What to do if you find too little
- Check your spelling. Search engines are incredibly literal-minded!
- Try alternate words. For example, rather than automobile try car.
- Try something more general. Instead of carrot, try vegetable.
- If your search string has several words, try leaving some out.
What to do if you find too much
- Try something more specific. Instead of food try vegetable.
- If your search string has only one or two words, add a few more that willnarrow down the choices.
How to Search for Information using Boolean Logic
Some search engines use "Boolean logic" under the heading, Advanced Search.Let's take a look at Boolean logic...What is Boolean Logic?
- Named after British mathematician GeorgeBoole
- Deals exclusively with truth and falsity
- Ideal for specifying whether something is what you're looking for(true) or is not what you're looking for (false)
Boolean Operators
There are three Boolean operators: and, or, not. Theyare used to determine the truth or falsity of combined propositions. Eachoperation is simple, though when they are combined, Boolean propositionscan get quite complex. We will only introduce the topic here.Here's an example: suppose your are looking for information about theWhite House. The Boolean propositions in their simplest form are (1) thata document contains the word white, and (2) that the same documentcontains the word house. How would the three Boolean operators work?
And
- The and operator will produce a true result if bothpropositions are true; otherwise, it will produce false.
- We are looking for documents and Web pages that contain both whiteandhouse.Documents that have the word white but not house won't meetour needs. Those that have the word house but not white won'thelp either. Both must be there, so we need our search engine to use theandoperator.
- This illustration shows how the and operator only returns truefor documents that contain both white and house (the overlappingarea, colored red).
- Not all search engines use the same way of letting you enter Boolean and.You have to read the Help documentation to find out!
Or
- The or operator will produce a true condition if eitheror both of the propositions are true. It is only false if neither propositionis true.
- What would our search results look like if the search engine looked forwhiteorhouse?It would return documents with either word in them - probably hundredsor thousands of them!
- The illustration shows that or returns all documents with the wordwhiteorthe word house.
- As with the and operator, you have to read the Help documentationto learn how each search engine lets you use the or operator.
Suppose you needed to learn about the White House before Bill Clintonbecame President. You would want the search engine to exclude documentsthat relate to Bill Clinton's time; for that, you need the not operator.To the two Boolean propositions above, we would want to add a third: (3)President Clinton's name does not appear in the document. (Note: this mightnot find all the most useful documents, but it illustrates the Booleanoperators!)Not
- This operator will change the logical truth or falsity of the propositionit is attached to. In other words, if a word is found in a document, notwill change the result to false. If the word isn't found, notwill change the result to true.
- In our example, the Boolean statement would be white and house and notclinton.
- The illustration shows that adding and not clinton excludes thedocuments having the word clinton in them. Only documents with whiteand house that don't have clinton in them are returned toyou.
Another way to Understand Boolean Logic: Cow Diagrams
Many people find it useful to have an alternative way of looking at thistype of logic. Here's one that has helped lots of people...A cow sleeps late one morning. She wakes up in the barn, to findall her friends already out to pasture. In order to get to the pasture,she has to find her way through several gates. Only if the right combinationare open can she get out. If the wrong door is open, she may wander outonto the highway. If we can teach her Boolean logic, she may make it...
What is the Boolean statement using and, or and not that will tellthe cow which gates to go through to get to the pasture, without goingout on the highway? Click here for the answer.
Answer to the Cow's Problem
To get the cow out to pasture without becoming hamburger meat on the highway,she should go through:((Gate B and Gate D) or Gate C) and not Gate A
Notice the use of parentheses to group the choices. Many search engineslet you use parentheses in this way.
Back to the Cow Discussion
About this document...
Module W12c: How to Find World Wide Web Sites
This document is part of a modular instruction series in Computer InformationSystems.
Closely related:- Web Search Engines (W12b)
- World Wide Web Treasure Hunt: Finding World Wide Web Sites (W13h)
For more information, see the overviewor the list of modules in this series, W- (World Wide Web). This documenthas been used in the following classes: CIS100, CIS101, CIS160Review:
W12cr
- Author:
- LaurenceJ. Krieg
- Institution:
- Departmentof Computer Information Systems, WashtenawCommunity College
- History:
- Original: 27 November 1995
- Latest revisions: 13 November 1998; review added 19 March1999
- Copyright:
- Copyright © 1996, 1998 Laurence J. Krieg.
Instructors: You may point to this file in your Web-basedmaterials.
Students: you may make a copy for your personal use.
All other uses: contact the author, LaurenceJ. Krieg for permission.
Original document sponsored in part by CoNDUIT (1994-1996)
CoNDUIT is a registeredservice mark of the Society of ManufacturingEngineers. CoNDUIT was funded by the U.S.Department of Energy under Cooperative Agreement No.DE-FC05-94OR22341,as part of the Defense Advanced ResearchProjects Agency's TechnologyReinvestment Project. Statements contained on these pages do not necessarilyreflect the views of the Department of Energy, DARPA, or the U.S. Government.