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Learning More about Search Engines and Subject Directories: FAQs

Here's a set of FAQs on how to use Internet Search Engines and Subject Directories for those of you wanting to find information on the Internet but not sure how to go about doing that.

FAQ#1: What's an Internet search engine?

FAQ#2: How does a search engine know about the millions of documents on the Internet?

FAQ#3: What's an Internet subject directory?

FAQ#4: What's better - a search engine or a subject directory?

FAQ#5: How can I improve my use of search engines?

FAQ#6: What's a wild card and how do I use it?

FAQ#7: How do I narrow a search?

FAQ#8: How do I widen a search?

FAQ#9: How do search engines deal with boolean operators?

FAQ#10: What's a "meta" search engine?

FAQ#11: What are some effective search strategies?


FAQ#1: What's an Internet search engine?

One way of finding information on the Internet is to use a "search engine". This is an Internet tool which will search for Internet sites containing the words that you designate as a search term. It provides results back to you in the form of links to those sites which have the term(s) you're looking for.

For example, if you wanted to see if there were any math lesson plans on the Internet that you could borrow, you might enter "math and lessons and plans" as your search term. After a brief wait, you would receive a web page with dozens of links to sites which had those particular words somewhere in the site.

It's important to understand that search engines DO NOT search the Internet itself. They DO search databases of information ABOUT the Internet which the company hosting the search engine has developed. Each search engine looks through a different database and that's why they each will reach different results from exactly the same terms. The degree of detail recorded by search engines varies greatly. For instance, some may enter the entire text of the document into a searchable field and others may only enter a short description. This is only one way in which search engines differ. Another difference is in the level of sophistication employed by the search engine when it looks through its database.

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FAQ#2: How does a search engine know about the millions of documents on the Internet?

Search engines do not search the Internet itself, but instead search a database of information about the Internet. Thus, when a document is placed on the Internet, it will only be found by a search engine if information about that document has been recorded in the search engine's database. There are at least two ways a search engine finds out about a document. One way is for the publisher of the document to register it with the engine. If a document publisher wants to ensure that a document is "found" by search engines, then the publisher will usually register with as many engines as possible. The second way that documents get registered is if the search engine company finds it as part of its research routines. Some search engines use "spiders" or search robots to search the Internet and gather information which is subsequently recorded in the engine's database.

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FAQ#3: What's an Internet subject directory?

Subject directories organize Internet sites by subject, allowing users to choose a subject of interest and then browse the list of resources in that category. Users conduct their searches by selecting a series of progressively more narrow search terms from a number of lists of descriptors provided in the directory. In this fashion, users "tunnel" their way through progressively more specific layers of descriptors until they reach a list of resources which meet all of the descriptors they had chosen.

For example, if you were using the Yahoo subject directory to find math lesson plans, you would start at the top level of the directory where there are approximately 15 general categories, including "arts and humanities", "government" and "education." Selecting "education" would lead to a list of about 35 descriptors, including "higher education", "magazines", and "teaching." Selecting "teaching" would lead to another page of resources all about teaching - including "English", "K-12", and "Math." This last choice would reveal a number of actual resources for the math teacher.

It's important to understand that a subject directory will not have links to every piece of information on the Internet. Since they are built by humans (rather than by computer programs), they are much smaller than search engine databases. Moreover, every directory is different and their value will depend on how widely the company searches for information, their method of categorizing the resources, how well information is kept current, etc.

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FAQ#4: What's better - a search engine or a subject directory?

There is no hard and fast answer to that question. A lot depends on the personal preferences of the user. Some people like directories because the user can control the search pattern, varying the path through the descriptors if another descriptor looks promising. Directories allow users to browse and to be more vague or general in their search term. Search engines leave the searching pattern to the computer program and can be used to find more specific resources.

A weakness of directories is that you must depend on the descriptors provided by the company. If these are not specific enough for you, then your search may be unsuccessful. As a result, directories can be good for finding general information, but not too successful in locating specifics. Also, the number of resources that you can find in a directory is generally far less than through a search engine.

A weakness of the search engines is the very extensive amount of hits that they can produce. A general search term could produce thousands of hits - far too many to be of much value. Knowing how to conduct searches is a skill and there is a learning curve. The next several FAQs provide information on how to develop search skills.

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FAQ#5: How can I improve my use of search engines?

You can get better results from an Internet search engine if you know how to use wildcards and "Boolean operators." Wildcards allow you to search simultaneously for several words with the same stem. For example, entering the single term "educat*" will allow you to conduct a search for "educator", "educators", "education" and "educational" all at the same time.

Boolean operators were named after George Boole (1815-1864) who combined the study of logic with that of algebra. Using the boolean operator "and", it is possible to narrow a search so that you get quite a limited set of results. Another common operator is "not" which acts to limit a search as well. The boolean operator "or" has the opposite effect of expanding a search. Using boolean terms, you can have the search engine look for more than one word at a time. Here are three examples of such search terms.

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FAQ#6: What's a wild card and how do I use it?

A wild card is a special character which can be appended to the root of a word so that you can search for all possible endings to that root. For instance, you may be looking for information on the harmful effects of smoking. Documents which contain the following words may all be useful to your search: smoke, smoking, smokers, smoked, and smokes. If your search engine allowed wild cards, you would enter "smok*". In this case, the asterisk is the wild card and documents which contained words that started with "smok" would be returned.

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FAQ#7: How do I narrow a search?

The boolean operator "and" is the most common way to narrow a search to a manageable number of hits. For example, with "heart and disease" as the search term, an engine will provide links to sites which have both of these words present in a document. It will ignore documents which have just the word "heart" in it (e.g., heart transplant) and it will ignore documents which have just the word "disease" in it (e.g., lung disease, disease prevention). It will only make a link if both of the words are present - although these do not necessarily have to be located beside each other in the document.

For even more narrow searches, you can use "and" more than once. For example, "heart and disease and prevention" would limit your search even more since all three terms would have to be present before a link would be made to the document.

The boolean operator "not" narrows the search by telling the engine to exclude certain words. For example, the search term "insecticides not DDT" would give you links to information on insecticides but not if the term "DDT" was present.

It is possible to combine two different operators. For example, the term "endangered and species not owl" would give you information on various kinds of endangered species - both of the words "endangered" and "species" would have to be present for there to be a hit. However, you would not get information on any owls that are endangered since the "not" term specifically excludes that word.

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FAQ#8: How do I widen a search?

The boolean operator "or" will broaden your search. You might use "or" if there were several words that could be used interchangeably. For example, if you were looking for information on drama resources, using just that one search term might not give you all that you wanted. However, by entering "drama or theater", the search engine would provide a link to any site that had either of those words present.

For even wider searches, you can use "or" more than once. For example, "drama or theater or acting or stage" would provide a very broad search indeed.

It is possible to combine boolean operators in a complex set of instructions through the use of parentheses, however that topic is beyond the scope of these FAQs. Look for information on advanced search strategies if your want to learn more.

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FAQ#9: How do search engines deal with boolean operators?

The short answer to that question is - "not consistently". Some engines allow the use of just a few operators while others provide access to a wide range. Some require you to enter the operator yourself while others have you select the operator from a pop-up box. Some allow you to do any kind of search from the main search page while others require you to go to an "advanced" page to conduct boolean searches.

Some engines allow you to enter several words into the search term WITHOUT a boolean operator. However, some search engine will assume that there is an "or" operator between the words while others assume the desired operator is "and". Check what the engine's default operator is before you elect not to enter boolean operators.

Most search engines are pretty easy to use if you read their help information.

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FAQ#10: What's a "meta" search engine?

A meta search engine is a search tool that doesn't create its own database of information, but instead searches those of other engines. "Metacrawler", for instance, searches the databases of each of the following engines: Lycos, WebCrawler, Excite, AltaVista, and Yahoo. Using multiple databases will mean that the search results are more comprehensive, but slower to obtain.

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FAQ#11: What are some effective search strategies?

Decide whether a search engine or a subject directory will be the best vehicle. The more specific the information you need, the more likely you will want to use a search engine.

When using a search engine, be as specific as possible. The amount of information now on the Internet can be overwhelming. To narrow down your search results to manageable numbers, use a search engine that allows the use of boolean operators and enter as many keywords as possible.

Get used to more than one search engines. You will develop a preference for a certain engine and it may work well for you but don't forget the other search engines and, from time to time, try another engine or a meta engine to ensure that you have achieved good coverage of the Internet.

Read the "tips" files provided by most engines. You'll be surprised to find out little things that make life easier. For instance, AltaVista allows you to use the "+" symbol instead of writing out the word "AND" when you use boolean operators.

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