Transcript Document

Lesson Four
Searching Effectively on the
World Wide Web
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.
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.
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")
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.
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.
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.
Comparison of Different Search
Tools: Search Engines
• Examples:
– AltaVista (http://www.altavista.com)
– Lycos (http://www.lycos.com)
– Google (http://www.google.com)
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.
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.
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.
Comparison of Different Search
Tools: Web Subject Directories
• Examples:
– Yahoo! (http://www.yahoo.com)
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.
Comparison of Different Search
Tools: Metasearch Engines
• Advantages:
– You can search several search engines at one
time.
Comparison of Different Search
Tools: Metasearch Engines
• Disadvantages:
– You may retrieve inappropriate Web sites
depending on how each individual search
engine interprets the search.
Comparison of Different Search
Tools: Metasearch Engines
• Examples:
– Dogpile (http://www.dogpile.com)
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.
Comparison of Different Search
Tools: Invisible Web
• Advantages:
– Can be useful for specific topics or unique
terms.
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.
Comparison of Different Search
Tools: Invisible Web
• Examples:
– Complete Planet
(http://www.completeplanet.com)
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)
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?
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?
The Differences Between Search
Tools
• Now, search Dogpile
(http://www.dogpile.com). "Go Fetch"
Joyce Brothers!
• How many results (hits) did you retrieve?
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?
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.
Before Starting a Search...
• Before beginning a search, think about
what you are looking for.
Effective Searching
• Once you have decided on a search
strategy, enter your search.
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?
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 widespread use of the Web.
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.
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.
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.
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.
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.
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.
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
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.
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.
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/5locate
/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).