Qwiki is a search engine that returns results in the form of a video. You type in a topic, and a video is played explaining the subject. Try it out at Qwiki.com.
Now Qwiki has provided a free app. Teachers can quickly provide their class with information about most any topic. Get the Qwiki app here
Disclaimer – please preview content before showing to kids, as some results may provide content you don’t want previewed with elementary students especially when related to health topics. With that said, most of the topics I previewed I’d endorse as fine in front of any students.