When you are adding images, videos and other content that you did not create to your presentation, it is important to make sure that you are not violating anyone's copyright. One way to do so is to find public domain images for your presentations. Copyright.gov explains the public domain as follows:
"A work of authorship is in the 'public domain' if it is no longer under copyright protection or if it failed to meet the requirements for copyright protection. Works in the public domain may be used freely without the permission of the former copyright owner."
Because such works can be used without first seeking permission, they are ideal for many projects, particularly those that will extend beyond educational uses.
Works fall into the public domain for three main reasons:
1. the term of copyright for the work has expired;
2. the author failed to satisfy statutory formalities to perfect the copyright or
3. the work is a work of the U.S. Government.
As a general rule, most works enter the public domain because of old age.
Use the Digital Copyright Slider Tool to determine is a work is still protected by copyright.
Note: Even if a work that you use is in the public domain, it is advisable to provide attribution for the work or, at a minimum, keep a record of the attribution of the work, so that you or other interested parties can find it later if necessary.
