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Boolean Operators. Locating Information The number of documents on the web have multiplied immensely over the last few years This means there is simply.

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Presentation on theme: "Boolean Operators. Locating Information The number of documents on the web have multiplied immensely over the last few years This means there is simply."— Presentation transcript:

1 Boolean Operators

2 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

3 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.

4 Search Engines Yahoo Excite Infoseek Askjeeves Google Are all types of search engines!

5 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.

6 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 dont want to search the entire library for a single book! Search Engines

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

8 How do I get the information Im 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 Search for Disney How Many Hits? Open Word and write Activity 1 then write the number of hits down on your information sheet.

9 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.

10 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.

11 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 wouldnt use the internet much.

12 Boolean Logic Boolean Logic helps you limit your search by using key words and operators. Symbols or special words used to perform computer operations.

13 Search engines use Boolean Logic to conduct queries. George Boole, a nineteenth century mathematician, invented this system of logic.

14 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.

15 Boolean Operators The real benefit of using operators 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.

16 Using Boolean Operator to Search Search is a process of trial and error. Different combinations can lead to drastically different results.

17 Using Boolean Operators to Search Its better to spend a little extra time narrowing down your search than following every hit you get.

18 Using Boolean Operators to Search Most search engines are not case sensitive so the operators do not need to be in all CAPS.

19 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.

20 Activity 2 Using 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.

21 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 Key dogs AND Labrador OR retriever In the search box. Click the search button to view your results.

22 Activity 2 Answer Chart Using AND/OR/+ Application Activity DogsLabradorRetriever 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.

23 Activity 3 Using (NOT/-) Sometimes its 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.

24 Some, for example, require you to include AND with the NOT operator, For example Simpsons AND NOT Homer Go to What was the difference between the 1 st query (number of hits) and the last query (number of hits)? Number of Hits SimpsonsSimpsons without Homer Simpsons without Homer and Bart Simpsons without Homer, Bart, and Lisa Record the hits on your information sheet.

25 Activity 4 ~ Application Activity Go to 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 SymptomsCarbon Monoxide and Symptoms and not Equipment Activity 4--Record the hits on your information sheet.

26 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)

27 Credits Computer Technology Course Curriculum ETC Technology Center Handout ETC Technology Center Instructors

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