Sweet Search is a search engine that searches only the sites that have been reviewed and approved by a team of librarians, teachers, and research experts. In all there are 35,000 websites that have been reviewed and approved by Sweet Search. In addition to the general search engine, Sweet Search offers five niche search engines. The niche search engines are for Social Studies, Biographies, SweetSites (organized by grade and subject area), School Librarians, and Sweet Search 4 Me (for elementary school students).
Sweet Search can be used by visiting the site directly or you can embed Sweet Search widgets into your blog or website.
Applications for Education
If you're concerned about your students stumbling onto sites that aren't reliable, try having them use Sweet Search. You could accomplish the same thing by creating a Google Custom Search Engine, but Sweet Search has already done essentially the same thing for you. Put one of the Sweet Search widgets into your classroom blog or school website so that students can search reliable sites within a familiar context.
Here are some related items that may be of interest to you:
How Web Search Works
Lesson Plans for Teaching Web Search Strategies
How to Create a Custom Search Engine