There are a number of reasons that an educator would want to 'capture' or copy the contents of a web-site. A major one would be that if a lesson plan calls for a site to look a certain way, you can only guarantee static content if you've captured the site as you want it to look for your lesson. Sites go down or change, so if you rely on one looking a certain way, use a capture program to grab it. Keep in mind, however, that most sites are copyrighted and shouldn't be changed or used for any commercial venture.

As well, the site may be your own and you want to create a back-up of it.

HTTrack Website Copier  is a free program that lets you download a site from the Internet to your computer, including images and supporting files.