Unit 1—Computer Basics Lesson 3 The Internet and Research
Objectives List some reasons for searching the Internet. Describe different search approaches. Explain how search engines work. Computer Concepts BASICS -
Identify some of the more popular search engines.
Objectives (cont.) List some of the specialty search engines. Describe some search tips and tricks. Describe the subject directory search approach. Computer Concepts BASICS -
Describe the invisible Web.
Why Search the Internet? Reasons that people search the Internet Research for school assignments Looking for medical and scientific information Travel information and accommodations Computer Concepts BASICS -
Shopping for goods and services
Internet Search Tools There are two basic types of Internet search tools: Perform searches based on keywords Search by specialized topics What is the difference between them? Search engines are automated. Computer Concepts BASICS -
Directories are assembled by people.
What Is a Search Engine? Search engines are programs that allow you to search for information. There are hundreds of search engines on the Internet. Search engines allow keyword searching. Some support concept-based searching. Computer Concepts BASICS -
The list of results returned from your search are called hits .
Search Engine Components Search engines usually have three main components. The search engine program that does the search of its database A spider or crawler that looks for the information in the database Computer Concepts BASICS -
The index that is built from information returned by the spider
Keyword Searches Keyword searches look for specific words within a Web page. Many search engines use meta tags to build their search index. Computer Concepts BASICS -
Meta tags are HTML tags in a Web page that do not display, but can be used to define page content.
Keyword Searches (cont.) Search engines also use significant words to build their index. Significant words may be words mentioned near the beginning of a page or repeated frequently throughout the page. Computer Concepts BASICS -
Some search engines claim to index all words in a Web page.
Keyword Search Steps To search using keywords: Connect to the Internet and go to a search engine site. Enter your keywords in the search box. Many search engines allow you to enter a phrase or sentence. Computer Concepts BASICS -
The search engine examines its internal database index looking for your words.
Keyword Search Steps (cont.) To search using keywords (cont.): The search engine returns a list of hyperlinks (hits) to Web sites containing your words. Click a hyperlink to go to that site. Computer Concepts BASICS -
If you get no hits on your search, revise your keywords and try again.
Major Search Engines Although there are hundreds, these are some of the more well known search engines: Computer Concepts BASICS -
America Online at aol.com
Specialty Search Engines These also are called category-oriented search engines. They are commonly used for Finding shareware and freeware Computer Concepts BASICS -
A Specialty Search Web Site Computer Concepts BASICS - This figure shows the Beaucoup Web site page. Note the various categories of information available. Clicking a sub-category will bring up a new page of categories until you find the exact topic you are searching for.
Tools and Techniques for Searching Computer Concepts BASICS -
Some commonly used techniques
Phrase Searching This is used to search for words that must appear next to each other. Phrases must be enclosed in double quotation marks. “ Books on the Civil War” Only sites with the exact phrase will be returned as hits. Computer Concepts BASICS -
You should capitalize proper nouns.
Search Engine Math Use math symbols to enter formulas or to filter out unwanted listings. A plus sign ( + ) before a word means it must appear. Computer Concepts BASICS -
A minus sign ( - ) before a word means it should not appear.
Search Engine Math (cont.) Examples of search engine math To search for sites that contain both cookies and recipes, enter Computer Concepts BASICS -
To exclude sites that have coconut cookie recipes, enter
Boolean Searching Boolean logic is similar to search engine math, but is more powerful. Boolean logic consists of three operators: AND: Search for sites that include Word A AND Word B. NOT: Search for sites the include Word A but NOT Word B. Computer Concepts BASICS -
OR: Search for sites that include Word A OR Word B.
Wildcard Searching Wildcard searching allows you to search for words for which you may not know the spelling or to search for plurals or variations of a word. Computer Concepts BASICS -
The wildcard character ( * ) lets you search for any word that has the characters before or after the wildcard character.
Wildcard Searching (cont.) To search for the element potassium without knowing how it is spelled, enter Computer Concepts BASICS -
Not all search engines support wildcard searches.
Related Searching Some search engines have a related search feature. The search engine will return hits based on your search criteria and may also display a list of other sites that have information related to your search criteria. This can greatly improve the odds of finding the information that you want. Computer Concepts BASICS -
Note: Some sites call this feature similar pages or more pages like this .
Subject Directory Searching Subject experts personally examine Web sites and add the URL to a search engine if it meets standards. Computer Concepts BASICS -
Subject directories are organized by subject categories.
Subject Directory Searching (cont.) Each category has a collection of links to Internet resources. The resources are arranged by subject and displayed in menus. Computer Concepts BASICS -
You start at the top of a category and drill down from a generic start to a specific topic.
A Subject Directory Site Computer Concepts BASICS - This figure shows the Yahoo Subject Web site.
Advantages of Subject Directory Searches They usually provide a more guided approach than keyword searches. You are not searching the entire Web. The linked sites have been handpicked and evaluated. Most links include a description. Computer Concepts BASICS -
They produce better quality hits on searches for common items.
Popular Subject Search Sites Computer Concepts BASICS -
The Librarians Index: www.lii.com
Advanced Search Forms Computer Concepts BASICS - This figure shows the advanced search form for the AltaVista Web site. It is designed to assist you in performing advanced searches by providing text box options.
The Invisible Web Also known as the “deep Web” Computer Concepts BASICS -
Indexes searchable databases
Summary Search engines and directories are two basic tools that you can use to find information on the Web. People assemble directories; search engines are automated. A search engine is a software program. Computer Concepts BASICS -
Most search engines support keyword searches.
Summary (cont.) Concept-based searching occurs when the search engine returns hits that relate to keywords. Stemming relates to the search engine’s capability to find variations of a word. Computer Concepts BASICS -
Meta tags are special tags embedded in a Web page; many search engines use the tags to create their indexes.
Summary (cont.) Keywords describe the information you are trying to locate. Search engines contain a database of organized information. Some search engines use natural language. Computer Concepts BASICS -
A search engine has three main parts: the search engine software, a spider that searches for keywords, and an index.
Summary (cont.) Stop words, such as www , but , and or , are not indexed by many search engines. A search engine uses an algorithm to index Web sites. Specialized search engines focus on a particular topic. Computer Concepts BASICS -
Multimedia search engines focus on video, animation, graphics, and music.
Summary (cont.) Subject directories are organized by subject categories. Subject experts check the Web sites that are part of a subject directory’s database. Use double quotation marks around a set of words for phrase searching. Computer Concepts BASICS -
Use the plus and minus signs for inclusion and exclusion of words within a search.
Summary (cont.) Boolean searching uses the three logical operators OR, AND, and NOT. The * symbol is used for wildcard searching. Computer Concepts BASICS -
No single organization indexes the entire Internet.