Web Searching Skills

How do you find information on the web? There are two basic ways: one is to use a web tool called a search engine; the other is to "surf" the web. Both have advantages, but here we will focus on the former as it can more quickly lead to the type of information that will be useful for your chemistry class.

A number of search engines exist on the web: Excite!, Alta Vista, InfoSeek, Yahoo! or Lycos. There is no charge for you to use them, but since they are produced commercially, you will find advertising built right into them.

Which search engine should you use? It probably doesn't matter, as long as you learn to utilize fully its features. Here, we have chosen to use Excite, a search engine that is user-friendly, reasonably powerful, yet not to so great an extent that it overwhelms its users. Excite also has some helpful features, such as concept based searching, that you will utilize in Chemistry in Context.

Feel free to use other search engines as well; in fact, there are times that you will need to search using several different search engines. Why? No search engine can completely index the web. On fact, most don't even come close. If you can't find what you want, try a different search engine.

How to do a search

To use Excite (or any search engine) to locate information, you first must construct what is called a "query". A query is simply a way of telling Excite what you want to find. For example, if you want to find information about the weather in Boston (where you are going to present a poster on your chemistry project), you might simply type in "Boston, weather". There are other more specialized ways to speedily find the weather using Excite and we will explore these in the last section.

More generally speaking, queries in Excite are constructed in one of two ways:
(1) using regular language
For example: "What is the ozone layer?" or "ozone layer"
or,
(2) using words like AND, OR, NOT and NEAR
For example: "ozone layer AND depletion AND stratosphere NOT smog"

The former is called a natural language search; the latter is a Boolean search. Both can work well. For example, suppose that you wanted to search for information about ozone. If you just type in the word "ozone", you may find information about the ozone layer, ozone as an air pollutant, photochemical smog in large cites, household ozone generators or a variety of other contexts where ozone plays a role. Thus, you need to narrow your search. What exactly do you want to find out about ozone?

Let's say you are interested in changes in the ozone hole over the Antarctic. A good starting point would be:

For a complete description of the feature of Excite, including the use of + to require words and using a - to exclude words, see "Help on Making Queries". These features can help you narrow your search even more.

Search Tips

As you search, remember that:

• The better your query, the better chance you have of finding what you want.
  
• Freely use chemical terms, as these are likely to be quite specific. For example, terms such as isotope, polyethylene, Environmental Protection Agency, and radon (coupled with other terms) are less likely to bring up unwanted information than automobile, New York and tennis. In this regard, searching for chemical information is relatively easy.
  
• Use lots of terms - more is better. The more detail you provide, the greater the chance that your search engine can find exactly what you are looking for.
• Don't worry if you get thousands of hits. Use the first 10 or 20 and ignore the rest.
• Know the rules for using your search engine. For example, are quotes required? The use of "quotes" varies. In Excite, for example, you use quotes when you want a phrase considered as a unit, for example "acid rain" rather than "acid" and "rain".
• Watch your spelling. If you enter flourine instead of flourine, you will find nothing (except web sites that also misspell fluorine).
• When you aren't getting what you want, try your query on another search engine.
• Use more specialized ways to search when appropriate. These are described in the next section.

Here's where you might want to know about the special features of the search engine that you are using. If it is Excite for Web Servers, you can expect a "concept match" if you type in something in regular old English. What this means is that Excite will not exactly match the terms you submit; rather, it will search for documents that are a best match for the words in your query. Excite for Web Servers will also search for documents that are about the same concepts that your query describes, so sometimes Excite for Web Servers will bring back articles that don't mention any of the words in your original query.

What this means is that your query -- the description of your information need -- can be as detailed as you like. Don't worry about providing too many words; the more words, the better. Additional words in your query will help Excite for Web Servers figure out what concepts you're really interested in. On the other hand, Excite for Web Servers will do a pretty good job of figuring out what documents are interesting to you even if your query is vague.

Advanced Query Tips

Here are some suggestions for getting the best results out of Excite for Web Servers.

Use More Words
The easiest way to narrow your Excite for Web Servers search and the first thing you should try is to simply use more words in your query. Also try using the Query By Example option on the search results page.

Use + to Require Words
Put a plus sign (+) in front of a search word and Excite for Web Servers will make sure that ALL of the documents it returns contain the word. Example search: Travel +France.

Use - to Exclude Words
Put a minus sign (-) in front of a search word and Excite for Web Servers will make sure that NONE of the documents it returns contain the word. Example search: Jaguar -car -automobiles.

Use AND, OR, NOT, AND NOT, ( )
Excite for Web Servers supports full Boolean operators and syntax. You can use the AND, OR, NOT, and AND NOT operators, and parentheses ( ) for grouping. Example search: swimming AND (man OR woman).

Using a Plus Sign (+) to Require Words

What it does:
Excite for Web Servers will make sure that ALL of the documents it finds include the word(s) you specify as being required.

How to use it:
In your search text, put a plus sign (+) in front of words that must be in documents that Excite for Web Servers finds. Do not put a space between the plus sign (+) and the word. For example, to find documents about hockey, but only those with the term NHL in them you could enter:

hockey +NHL

What's different about it:
Without the plus sign (+), Excite for Web Servers looks for documents about any of the words in your search text. Excite for Web Servers will rank documents that have all of the words higher, but will also list documents that have only some of your search words as well as documents that may have none of your search words, but that appear to be conceptually related.

The downside:
You may miss related documents that don't have the words you specify as required. For example, the search "hockey +NHL" would not include documents that have the words National Hockey League, but not NHL.

Using a Minus Sign (-) to Exclude Words

What it does:
Excite for Web Servers will make sure that NONE of the documents it finds contain any word(s) you specify to exclude.

How to do it:
In your search text, put a minus sign (-) in front of words that must not be in documents that Excite for Web Servers finds. Do not put any space between the minus sign (-) and the word. For example, if you want to find documents about zeppelin aircraft but not the rock band Led Zeppelin, you could enter: Zeppelin -Led

What's different about it:
Without the minus sign (-), Excite for Web Servers looks for documents that are conceptually-related to all the search words you provide, rather than looking for items to exclude from the results.

The downside:
It's easy to exclude too much. For example, if you were looking for information on greyhound dogs and not the bus company, the search "greyhound -bus" would exclude a document that was all about greyhounds, but that had the sentence "the greyhound trainers arrived by bus."

Boolean Operators: AND, OR, NOT and ()

What they do/How to use them:
AND - Documents found must contain all words joined by the AND operator. Note that this is equivalent to putting a plus sign (+) in front of the word. For example, to find documents that have all of the words wizard, oz and movie, you could enter: wizard AND oz AND movie

OR - Documents found must contain at least one of the words joined by OR. For example, to find documents that have either the words cat or kitten you could enter: cat OR kitten

AND NOT - Documents found cannot contain the word after the term AND NOT. Note that this is equivalent to putting a minus sign (-) in front of the word. For example, to find documents that have the word pets, but not the word dogs, you could enter: pets AND NOT dogs

( ) - Parentheses are used to group portions of Boolean queries together. For example, to find documents that have the word fruit, and either the word banana or the word apple in them, you could enter: fruit AND (banana OR apple)

What's different about it:
Allows for excluding and requiring words, and complex combinations of words.

The downside:
It's often difficult to specify exactly what you want to include or exclude. You can also get unexpected results if you are not careful about your use of operators and parentheses. For example, the search bananas OR apples AND oranges is the same as the search bananas OR (apples AND oranges). Both queries will find documents that contain both apples and oranges, together with documents that contain the word bananas. However, the query (bananas OR apples) AND oranges is not the same. It will find documents containing the word oranges and, in the same document, either bananas or apples. Be careful out there!

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