A neat trick for finding many public domain resources has been thwarted by the partial government shutdown. Recognizing that the resources created by the Federal Government (images, video, documents), are funded by tax dollars, they are in the public domain thereby free (and great for education!). It may or may not be well known that a Google search for the thing you are looking for followed by site:.gov (all lowercase) returns to the searcher results limited to government websites. (e.g. hot air balloon site:.gov will result in many images from NASA and other .gov sites with hot air balloons that are in the public domain.
With the events of the past week, many of the Federal Government websites including the National Park Service’s Public
Domain Image Library, NASA and NIST are not available. Frustrating for people who like this great resource for presentations, webcreations, and multimedia projects, but it is good to be aware. Looking for some alternatives? Maybe not as diverse but the MorgueFile is one of many other great resources for education-friendly images.