INTERNET ESSENTIALSSearch Engines and Searching the Web

What you will learn•Search Engine Basics•Formulating Searches

The Web and E-mail 2

Search Engine Basics• A Web search engine

is a program designed to help locate information on the Web by formulating simple keyword queries.

Search Engines• A search engine is helpful in locating information for which you may not know the exact web address on• web pages on various topics• locating specific web pages• images • videos

• There are thousands of search engines available.

Search Engines & Types

Google Search engineLycos DirectoryAlta Vista Search engineYahoo DirectoryBing Search engineMSN DirectoryAOL DirectoryHotBot Search engine

The Different Types of Search Engines

• The term "search engine" is often used indiscriminately to describe: • Web crawler “search engines”• human-powered “directories”• Hybrids - uses both

Web Crawler

• Crawler-based search engines such as Google, compile their listings automatically

• They "crawl" or "spider" the web, and people search through their listings

• Spiders scour the web on a regular basis.• Listings are what make up the search engine's index or

catalog• The index can be defined as a massive electronic filing

cabinet containing copies of every web page the spider finds

Directories

• Directories depend on human editors to compile their listings• Webmasters submit an address, title, and a brief description of

their site, and the submission is reviewed

• After a web site makes it into a directory it is generally very difficult to change its search engine ranking

Hybrid search engines• Some search engines offer both crawler-based results

and human compiled listings called “hybrid search engines”.

• They typically favor one type of listing.• AOL usually displays human-powered listings. But uses

Google as a secondary engine.

Search Engine Basics• Search engines require you to enter a word or phase,

“search text” or “keyword” that describe the item you want to find

• They often respond with results that include thousands of results, whose content varies based on the information you are seeking.

Activity• Let test several search engines to see if we can determine

if it’s a directory or web crawler.• Have a couple students go the following search engines:

• Bing, yahoo, google and aol

• Have the student search for a specific item (i.e. Dr.J ABA)• Record the results from each search engine and the

discuss the result • Which do you think is a directory verses web crawler?• When would you want to use a web crawler vs a directory?

Formulating Searches

• Most search engines are not case sensitive (Shift key usage not necessary)

• Search engines ignore common words like:(and, a, & the) there is no need for them.

• To search for an exact phrase, enter it in quotation marks.

• The asterisk (*) is referred to as the wildcard charter.• *ball = baseball, football, basketball, volleyball

13

Boolean Search

• A Boolean operator is a word or symbol that describes a relationship between keywords, • Helps you create a more focused query• AND (+) - If words are joined by AND both words must appear

on a web page before it can be included in the results.• OR – If two words are joined by OR then either word or both

words could appear on a page.• NOT (-) – A keyword following a NOT must not appear on any

of the pages found by the search.

Example poverty and crime , poverty orcrime , poverty not crime

Boolean Reference Guide 

Phrase Boolean Logic 

Exact Phrase “Boolean Logic” 

And Boolean AND Logic +Boolean +Logic 

Or Boolean OR Logic

Boolean Logic  

Not Boolean AND NOT Logic +Boolean –NOT Logic

Truncation/Wild Card Boo* 

Activity• Record the number of hits and compare the results.• Search for:

Search Hits

Water

Pollution

+water +pollution

cowboys

cowboys -football

cowboys versus 49ers

"cowboys versus 49ers"

Activity: Internet search Practice

Directions: try to answer the following questions using an internet search engine.• 1. Who is the governor of North Carolina?• 2. Who is the president of Brazil?• 3. What is the capital of China?• 4. What is the approximate population of California?• 5. Who won the American league baseball world series in

1998?• 6. How fast can a cheetah run?• 7. How old was George Washington when he died?