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AND + Boolean Operators OR - NOT Locating Information The number of documents on the web have multiplied immensely over the last few years This means there is simply more information to search through to find what you need Locating Information

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locating information
Locating Information
  • The number of documents on the web have multiplied immensely over the last few years
  • This means there is simply more information to search through to find what you need
locating information3
Locating Information
  • Search Engines are improving all the time so that you can search more expertly and with less effort.
  • Boolean Operators are used to give your searches real power.
search engines
Search Engines
  • Yahoo
  • Excite
  • Infoseek
  • Askjeeves

Are all types of search engines!

what do search engines and card catalogs have in common
What do Search Engines and Card Catalogs have in common?

Search engines are used to catalog the web much in the same way that books are cataloged in a library. This makes information easier to find.

slide6

Search Engines

  • Search engines allow the user to look for information based on some criterion such as key words
  • This allows you to only look at information you are interested in.
  • You don’t want to search the entire library for a single book!
how do i get the information i m looking for
How do I get the information I’m looking for?
  • The problem is the sheer amount of information available.
  • Often a search will produce a list of hundreds, if not thousands of “hits”
  • Go to http://www.google.com
  • Search for Disney
  • How Many Hits?
what is a hit
What is a Hit?
  • Hits can refer to a couple of things.
  • Every time someone goes to a web page it counts as a hit.
  • Site owners often count the number of hits on their own site to judge its effectiveness in attracting users.
what is a hit10
What is a Hit?
  • In the case of looking for information hits are the number of items found in response to your search query.
  • For example, if your query results in a list of 25 items that meet your search criterion, then, the query resulted in 25 hits.
what is a query
What is a Query?
  • A “query” like a is a method of filtering data to find information that meets specific search criterion.
  • If you had to look at thousands of pages at random to find one or two containing useful information, then you wouldn’t use the internet much.
boolean logic
Boolean Logic
  • Boolean Logic helps you limit your search by using key words and operators.
  • Symbols or special words used to perform computer operations.
boolean logic13
Boolean Logic
  • Search engines use Boolean Logic to conduct queries.
  • George Boole, a nineteenth century mathematician, invented this system of logic.
boolean operators14
Boolean Operators
  • This system uses operators to manipulate data based on a simple “Yes” or “No” ranking system.
  • Add, Subtract, multiply, and divide are the primary operators of arithmetic.
  • AND, OR, and NOT are the primary Boolean Operators.
boolean operators15
Boolean Operators
  • The real benefit of using operator’s lies in combining them to refine your searches.
  • As you learn more about each operator, try refining your searches by combing operators.
  • Watch how your hot list shrinks to only a few most valuable pages.
using boolean operator to search
Using Boolean Operator to Search
  • Search is a process of trial and error.
  • Different combinations can lead to drastically different results.
using boolean operators to search
Using Boolean Operators to Search
  • It’s better to spend a little extra time narrowing down your search than following every hit you get.
using boolean operators to search18
Using Boolean Operators to Search
  • Most search engines are not case sensitive so the operators do not need to be in all CAPS.
using boolean operators to search19
Using Boolean Operators to Search
  • Some search engines already have a default operator.
  • Hotbot defaults to the AND search.
  • This requires every term in the search to get a hit.
activity 1 using and or try out activity
Activity 1Using AND/OR/+Try-out Activity

Go to Yahoo!

Key dogs in a search box and click search button. Yahoo will display all the categories with the word “dogs” in them.

Refine your search by adding an AND operator. Remember, search engines default to an AND search, so dogs AND breeds is the same as dog breeds.

Click the back button to return to the search box. Enter dogs and Breeds. Click the search button, and view your results.

activity 1 using and or
Activity 1Using AND/OR/+
  • Generally, the OR operator will expand a search to include more pages. It can be very helpful when used in combination with the AND operator.
  • Go to www.webcrawler.com
  • Key dogs AND labrador OR retriever In the search box. Click the search button to view your results.
activity 1 using and or application activity
Activity 1Using AND/OR/+Application Activity

Subject line for e-mail:Boolean Activity 1 Results

activity 2 using not
Activity 2Using (NOT/-)
  • Sometimes it’s easier to narrow a search by specifying what you are NOT looking for. The NOT operator excludes documents containing a keyword you specify.
  • Some search engines use the – symbol as the operator, which works the same way as the NOT operator. Be sure to check the instructions for using different operator on each search engine.
slide24
Some, for example, require you to include AND with the NOT operator, For example Simpson’s AND NOT Homer
  • Go to www.google.com
  • E-mail the number of hits for each scenario. What was the difference between the 1st query (number of hits) and the last query (number of hits)?

Subject line for e-mail: The Simpson’s

activity 2 application activity
Activity 2 ~ Application Activity
  • Go to www.altavista.com
  • In the search box enter “carbon monoxide poison AND symptoms” click the search button.
  • In tools click “Advanced Search”, then type “NOT” as the Boolean Operator
  • This time type “carbon monoxide poison and symptoms and not equipment. Notice the number of hits is reduced.
credits
Credits
  • Computer Technology Course Curriculum
  • ETC Technology Center Handout
  • ETC Technology Center Instructors