Boolean Operators

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• 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• Yahoo• Excite • Infoseek • Askjeeves• Google

Are all types of search engines!

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.

• 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!

Search Engines

•Some search engines offer indexes, so that you can search by category.

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?• Open “Word” and write Activity 1 then

write the number of hits down on your information sheet.

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 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?• 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 helps you limit your search by using key words and operators.

•Symbols or special words used to perform computer operations.

Boolean Logic•Search engines use Boolean Logic to conduct queries.

•George Boole, a nineteenth century mathematician, invented this system of logic.

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 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

•Search is a process of trial and error.

•Different combinations can lead to drastically different results.

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 Search

•Most search engines are not case sensitive so the operators do not need to be in all CAPS.

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 2Using 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 2 (Continued)Using 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 http://www.bing.com • Key dogs AND Labrador OR retriever

In the search box. Click the search button to view your results.

Activity 2 Answer ChartUsing AND/OR/+

Application ActivityDogs Labrador Retriever

Hits using Yahoo→

Dogs AND

Retrievers

Dogs AND

Labradors

Labrador OR

Retriever

Hits using Bing →

Create a chart on the “Word” sheet you used for activity 1 and record the number of hits for each section. Your Chart should look like the one above.

Activity 3Using (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.

• Some, for example, require you to include AND with the NOT operator, For example Simpson’s AND NOT Homer

• Go to www.google.com• What was the difference between the 1st query (number of hits) and the

last query (number of hits)?

Number of Hits

Simpson’s Simpson’s without Homer

Simpson’s without Homer

and Bart

Simpson’s without

Homer, Bart, and Lisa

Record the hits on your information sheet.

Activity 4 ~ Application Activity• Go to www.google.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.

Number of Hits

Carbon Monoxide and Symptoms

Carbon Monoxide and Symptoms and not Equipment

Activity 4--Record the hits on your information sheet.

E-Mail Information• Save your information sheet as Boolean Operators

Activities 1-4 in your Internet Unit folder. Make sure you have a header and footer on the information sheet. Open your E-Mail and attach your information sheet and send it to the teacher. Put Boolean Operators Activities 1-4 in the subject You should have 4 titles and under each title include the appropriate headings and number of hits.– Disney– Dogs (you should have 6 headings under this)– Simpsons (you should have 4 headings under this)– Carbon Monoxide (you should have 2 headings

under this)

Credits

• Computer Technology Course Curriculum

• ETC Technology Center Handout• ETC Technology Center Instructors