Ref Seek is a search engine designed for academic use. As you compare search results between Ref Seek and generic Google you will find that the second and third pages of search results on Ref Seek contain results that seem to be more "academic" than what is found on the second and third pages of a generic Google search.
Famhoo is another option for kid friendly searches. It draws on the collective results of the major search mainstream search engines like Google, AOL, and Yahoo. Famhoo simply provides a stricter family filter than the filters available on mainstream search engines.
Ask Kids is the kid friendly, kid safe version of the popular search engine Ask.com. Ask Kids is divided into five categories of which one is a general search option: School House (general), movies, games, images, and video. The School House category provides students with suggested topics and links to resources for those topics. Can refine searches based on a student's age.
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. Wolfram Alpha can be used for other searches, but it's not nearly as useful for general inquiries as it is for computational questions.
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, in other cases results will link to fully viewable documents.