One way of thinking of search systems is to compare them to refrigerators. They both hold content. I'll admit that refrigerators have tastier content for eating, but search systems can have some pretty "tasty" content for research and writing!
Take a look at the refrigerators below. (You can click on them to see bigger versions of the images.)
Just as refrigerators are similar but with different options and types of content, search systems are similar but with different options and types of content. By types of content, I mean that you'll probably find a different selection of food in your parents' refrigerator compared to a mini-fridge in a dorm room!
Think back to the different styles of refrigerators. There's both different content and different options. Do you want an ice maker? Do you prefer a top freezer or a side freezer? Search systems are the same way. Search engines only find the surface-level content: the free stuff. Databases find the deep content: the subscription stuff that costs money. Also, some databases search differently than others. They're all similar (subject, title, etc.), but just as those fridges have different freezer layouts, databases may have different search interface layouts. Keep that in mind with your searching and how you decide to explore your options.
Also, what about the food in those fridges? Some of it may be very tasty but not that good for you. The same thing happens with sources. Those popular sources may be fun to read, but they might not be good for your research.
Refrigerators = Search Systems
Food = Sources
Source evaluation is a deeper examination of your sources -- determining a source's type, characteristics, etc. From these evaluations, you'll then decide if a source is a good fit for your research.
Source types are more than just book, journal, webpage, etc. You'll also want to determine if the source is a popular or a scholarly source.
Here's a table that illustrates the differences between the two types of sources.
|Purpose||current events, entertainment, summary||research, communicating information|
|Audience||general||scholars, researchers, students|
|Authors||journalists, often unnamed||researchers, experts, always named|
|Characteristics||shorter length, informal, few citations||longer length, formal, more citations, peer-reviewed*|
Peer-reviewed articles have been reviewed and accepted for publication by a selected panel of recognized experts in the field of study covered by the journal (also know as the author's peers).
Source characteristics help you determine if the information from the source is reliable.