What is Copyright?

Copyright is the legal right (usually of the author or composer or publisher of a work) to exclusive publication production, sale, or distribution of some work. What is protected by the copyright is the "expression," not the idea. Taking another's idea is plagiarism.
                                                                    www.unmc.edu/ethics/words.html

Anytime you copy something, you must cite your sources. Your teacher will let you know whether to use MLA or APA style for citations. But you are also limited in how much you can copy without breaking copyright law:

TYPE OF MEDIA
PORTION LIMITATION
Motion Media
Up to 10% or 3 minutes, whichever is less, of a single copyrighted motion media work
Text
Up to 10% or 1000 words, whichever is less, of a single copyrighted work
Poems (text)
An entire poem of less than 250 words: no more than three poems by one poet, or five poems by different poets from a single anthology
In poems of greater length: up to 250 words but no more than three excerpts by a single poet or five excerpts by different poets from a single anthology
Music, Lyrics, and Music Video

 
Up to 10%, but not more than 30 seconds of music and lyrics from an individual musical work; Any alterations to a musical work shall not change the basic melody or the fundamental character of the work
Illustrations and Photographs

 
A photograph or illustration may be used in its entirety. No more than 5 images by an artist or photographer. Not more than 10% or 15 images, whichever is less, from a single published collected work
Numerical Data Sets
(spread sheets/databases)
Up to 10% or 2500 fields or cell entries, whichever is less, from a copyrighted database or data table; A field entry is defined as a specific item of information, such as a name or Social Security number, in a record of a database file. A cell entry is defined as the intersection where a row and a column meet on a spreadsheet.
Copying and Distribution Limitations
Only a limited number of copies, including the original, may be made of an educator's educational multimedia project.
No more than two use copies only one of which may be placed on reserve;
An additional copy may be made for preservation purposes but may only be used or copied to replace a use copy that has been lost, stolen, or damaged;
In the case of a jointly created educational multimedia project, each principal creator may retain one copy following the time and use restraints listed above