Finding What You Need on the Internet

What's the difference between a search engine and a directory? The distinction has become blurred, but in a nutshell, a search engine treats the Web like a database in which you search for Web pages that use a word or term. Some search engines focus specifically on finding graphics or resources in a particular discipline or even a particular geographical area. Search engines are available for finding sound files, and meta-search engines let you enter a term once, then send your request out to several other search engines. Directories, however, may or may not be based on search engines. They are organized by humans into subjects to help you find sites about a general topic, much like the card catalog at a library.

Whether to use one or the other is largely a factor of what you are looking for and how much you already know. For example, suppose you were doing a lesson on biology and wanted the kids to learn about Charles Darwin. You could enter his name in a search engine to get a list of Web pages where he's mentioned, then visit a few to see which ones were best. Search engines tend to be most useful when you're looking for something specific. Now, suppose that you first wanted to introduce the kids to the topic of evolution in general before getting to Darwin. You could search on the word "evolution," but it's a common word used in many contexts, from "the evolution of democracy" to a rock band named Evolution. Your search would turn up millions of hits around the world unless you were using a highly specialized biology search engine. Instead, you're better off using a directory to work through a directory structure from Science to Biology to Evolution and so on.

The more specific your search term, the more valuable a search engine will be. Even a specific name like "Charles Darwin" can turn up thousands of hits because he is such an important figure in science, history, philosophy and more. Remember, search engines involve hundreds of thousands of sites around the world. (We ran Darwin's name through Lycos, a popular search engine, and got 124,306 mentions—way too many to visit each one!) One of the big differences between a search engine and a directory is that searches find individual Web pages, whereas directories organize Web sites. A site dedicated to Charles Darwin would likely have dozens or even hundreds of mentions of his name, and each page at that site would appear as another listing in a search; in contrast, the directory would only mention the existence of the whole site.

Because the Web contains so much unstructured information, using search engines is actually becoming a science in its own right. All good search engines offer what are often called "advanced search features," which allow you to restrict your searches in certain ways. For example, if you were researching Darwin's work with turtles on the Galapagos Islands, a search for "Charles Darwin AND turtles" would only list pages that contained both terms. New search engine technologies are based on natural language or artificial intelligence that allow you to ask human-type questions rather than just enter key words. For example, if you were trying to learn more about evolution quickly, you could type in "What is survival of the fittest?" or "Who had the first theory of evolution?" Special programs that mimic the way humans think then go out and sort through all the pages automatically to find the ones that best answer each question. Further exploration of search engines is a great project for older kids, one that will give them valuable skills for careers as librarians, corporate researchers, legal support and more.

Below are many resources for navigating the Web as well as specific places to find educational resources.