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.
KidRex is a new kid-safe search engine powered by Google custom search. KidRex uses a combination of Google's safe search mode and their own database of filtered keywords, phrases, and websites.
Ref Seek is a search engine designed for academic use. Ref Seek seems to eliminate the advertising and paid links found on Google, Ask, Yahoo, and other commercial search engines. Ref Seek's intention is to serve only search results that are academic in nature.
Wolfram Alpha is billed as a computational search engine and this is exactly what it does. If students have any questions involving numbers, Wolfram Alpha is the place to go.
Google Scholar is one of Google's lesser-known tools. Google Scholar is a search engine designed to search scholarly journals, Supreme Court records, and patent records. In some cases the results will link to abstracts of books and articles that you will then have to obtain from a library or book retailer. In other cases results will link to fully viewable documents.