6.2 Demonstrate knowledge of search logic, search engines and features of the Internet

Table of Contents

1. Introduction
   1. Boolean logic
   2. The Boolean operators
   3. Logic diagrams: the AND operator
   4. Logic Diagrams: the OR operator
   5. Logic Diagrams: the NOT operator
   6. Using multiple Boolean operators
   7. Constructing precise Boolean searches
   8. Search engine assumptions
   9. Advanced search facility
   10. Advanced searching on Yahoo
   11. Other points on Boolean searching ...
2. Truncation and wildcards
3. Grammar of the Internet
4. Search engine operation
5. Ownership of the web
6. Dark internet and the invisible web

The Boolean operators

There are three Boolean operators - AND, NOT and OR. We will explore how each of these is used.

AND is used to link search terms.

Entering an expression such as beans AND toast means that results will be returned only where both words appear. Using the AND operator narrows your search and gives a smaller number of results.

OR is used to indicate that any of the terms may be present.

Entering an expression such as punk OR hair means that results with either one or the other (or possibly both) will be returned. Using the OR operator widens your search and gives a larger number of results.

The OR operator is particularly useful where a topic might involve synonyms or near synonyms. A search for illness AND felines OR cats will be more wide ranging than illness AND cats.

NOT is used to exclude terms.

Entering an expression such as pop music NOT beatles might be devised to return results about pop music but excluding results about the Beatles. Using the NOT operator narrows your search and gives a smaller number of results.

The NOT operator is particularly useful when one of your search terms had more than one meaning. Telegraph might refer to electronic communication methods but it is also a common name for newspapers. A search for telegraph development NOT newspaper will eliminate press information.

In fact the expressions are pretty close to what you would say in natural speech:

I am looking for references to both beans AND toast.

I am looking for sites on either punk OR hair

I am looking for information on pop music but NOT including the Beatles.

Sometimes this is easier to understand in diagrams, so let's have a look at Logic diagrams ...