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Search Engines are programs that enable you to search the Internet using categories, keywords, or questions. A search engine keeps records about millions of web pages and other Internet resources such as newsgroup postings. Some use "robots" which are programs that spend their time finding web pages and noting which words are on which pages. Other search engines (called subject directories) are created by people who look at new sites and index them according to different categories. There are several popular search engines and subject directories on the Internet: Yahoo, AltaVista, Lycos, Excite, Magellan, and Webcrawler are just a few.
In order to begin a search, open a web browser. Now you can decide: do you know which search engine you want to use? If you do not, click on the "Search" button, found on most browsers. You will go to a page where one of the many search engines will be selected for you to perform your search.
Not all search engines work search in exactly the same way, but essentially they perform the same function. You can try searching for the same topic in several different engines to determine how they work and how they may fit the requirements for your particular search. One of the drawbacks to the web is that there are so many millions of pages that no one search engine can find everything. Another factor is that search engines do not know if the information they retrieve really is valid, or is what you were looking for. They are simply fulfilling a command to send you a list of sites that contain the keywords or subject you requested.
The two most common ways to search are by subject or keyword. A subject search is useful if you want information on a general topic. Yahoo (http://www.yahoo.com) is a popular place to conduct this type of search. At the top of Yahoo's main page is a box containing a list of general categories (i.e., Education, Entertainment, Science, Travel, etc.). If you click on one of these categories you will be taken to a list of subcategories related to that topic. Each of these links takes you to a page with more related categories. The broadest topics are first, and they get more specific as you go deeper. Eventually, you should find a page with a list of links related to your topic. To find pictures taken by the Hubble Space Telescope, you might follow these links: Science, Astronomy, Astrophotography, Pictures, and finally Hubble Space Telescope.
A keyword search is a little different in that it searches web pages for the word(s) that you indicate and returns a list of sites that contain that word. Most search engines have a text box at the top of the main page that allows you to type in the words you are searching for. The words you type are referred to as a "search string" or "query string." Sometimes a search can return a very large number of web pages. Then you sort through these pages to find which ones really do contain the information you were looking for. There are many strategies for narrowing down your search so you get more relevant results.
Some search engines allow you to try a "natural language" query, which means you ask a question in ordinary spoken English (which you type into a text box), and the search engine interprets the request and sends a list of the closest matching answers. AskJeeves (http://www.aj.com) and the version for children (http://www.ajkids.com) are examples of this kind of search engine. For example, you type in a question such as, "What time is it in the Philippines?" and Jeeves will present you with a list of related questions that should contain the answer to your question. You choose the question that appears to be the most relevant. Jeeves will not always have an answer for you, but will refer you to another search engine to continue your search.
Some search engines are experimenting with having a variety of search services combined in one. Many of them provide both a subject directory and keyword search, and other services such as news updates, electronic maps, online shopping and free email. Some are also adding the Ask Jeeves type of natural language query.
With all of these choices and varieties of searching techniques available, finding the exact piece of information you are looking for can be a complicated task. One strategy many people use is to find two or three search engines that generally provide adequate results, and then learn to use them very well. Help pages with searching tips and advanced level search techniques are available from most search engines' main pages. Taking a short amount of time to learn how a particular search engine works can help you get more relevant results and save you a lot of time browsing through long lists of results. The following paragraphs give a detailed description of common search strategies used by popular search engines.
Let's say you wanted to find information on cave-dwelling bats. You would connect to the Internet, open a web browser, and choose a search engine (in this case Altavista). At the top of the page is a text box where you type the keyword (bats) and then click the search button. Altavista will return a page with a list of "bat" related sites. You may see a section of the page that says, "Altavista knows the answer to the following questions" and then a question along the lines of, "Where can I find a concise encyclopedia article about bats?" If there is a link to a page that appears to answer your question, you are finished. But suppose you do not find what you were looking for? There will also be a list of pages that contained your keyword of "bats." Suppose 52,250 documents match your query. This doesn't mean that all 52,000 documents are about bats, it means that the word bat appears on the page. It may be that the word bat is mentioned only once in the context of something else. 50,000 web pages are a lot to look through. How can you narrow this focus to find what you are specifically looking for?
There are several ways to narrow the number of hits you get, depending on what type of information you are looking for. If you type the search string: +bats +animals, you might get about 5,000 hits this time. Five thousand is still a lot, but you have cut the number of hits to one tenth of what it was before. The addition signs in the string tell the search engine to return only pages containing the word after the addition sign. The addition sign in front of the first word is important. Without it, the search engine will only require the second word to appear on any page it returns; the first word may or may not appear.
Try the search string: +bats -baseball. The minus sign tells the search engine to exclude any pages that contain the word appearing after the minus sign. There are approximately 37,000 hits for this query. Clearly, searching for "bats which are animals" is not the same as searching for "bats which aren't related to baseball." Remember, there are other types of sports which use bats: cricket is one example. Using the addition and subtraction operators requires some forethought to figure out which is most likely to give you the results you want.
If you look at the list of links that your search for +bat -baseball generated, one of those listed may say something like "Louisville Slugger Bats." Why? You told the search engine to exclude pages about baseball, right? Not exactly. You told it to exclude pages that use the word "baseball," which is slightly different. While it is usually safe to assume that pages about a subject will all use certain words related to that subject, it is not always the case. In this instance, the word "baseball" does not appear anywhere in the text of the "Louisville Slugger Bats" page. Search engines are not perfect. They can reduce the amount of work you have to put into finding something, but you still have to carefully sift through the information they return.
Another way to narrow your search is through the use of quotation marks. If you were to search the string: medical school (no pluses or minuses) you would get something like 6.4 million hits. You might think that by typing this string or the string +medical +school might give you information on medical schools. It would, but it would also give you a great deal of information you do not want. The search engine looks for the words used in the search string that occur anywhere on the page, they do not necessarily have to be next to each other. So your search will return pages about other types of schools but somewhere mention the word medical, or pages using the term medical and somewhere use the word school. To get the search engine to find the exact phrase medical school, put the words in quotation marks, "medical school." Some search engines will only return that exact phrase even including capitalization (you would not see "Medical School" or "MEDICAL SCHOOL") but others are not case sensitive. Consult the help pages of the search engine you are using to see how it handles quotations.
To find words that appear near each other but not necessarily next to each other, use parentheses around the words. If you search for (medical school) you will find links to pages containing phrases such as "medical and dental school" as well as just "medical school."
Remember, there are four common ways to narrow a search:
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