Section 102(a) of the Copyright Act defines what is protected; “Copyright protection subsists, in accordance with this title, in original works of authorship fixed in any tangible medium of expression…” (italics added)
It goes on to state, “Works of authorship include the following categories":
(1) literary works;
(2) musical works, including any accompanying words;
(3) dramatic works, including any accompanying music;
(4) pantomimes and choreographic works;
(5) pictorial, graphic, and sculptural works;
(6) motion pictures and other audiovisual works;
(7) sound recordings; and
(8) architectural works
The amount of time an item is covered by copyright is not limitless. So, while some works are never protected by copyright, other items that are protected by copyright can have that protection expire. In both of these instances, items are considered to be in the "public domain".
What does it mean when something is in the public domain? It is no longer under copyright protection and can be used freely by anyone.
Here are two ways to check to see if a copyright has expired and/or if a work is in the public domain:
Ideas are not copyrightable nor are speeches that haven't been written down. The material must be in a "tangible form of expression" before a copyright can be attached to it.
Items used commonly - such as a calendar or a list without creativity - like a phone book, are also not eligible for copyright protection.
Other material that is not covered by copyright are government documents. These include bills, laws, congressional reports, census studies and all other types of material in which the federal government is involved in publishing.
Section 102(b) of the Copyright Acts states that "In no case does copyright protection for an original work of authorship extend to any idea, procedure, process, system, method of operation, concept, principle, or discovery, regardless of the form in which it is described, explained, illustrated, or embodied in such work."