After I found Crash Course Kids, this YouTube channel, SciShow Kids, was in the suggestion list so I decided to check it out.
The SciShow Kids channel answers the many questions of "Why". The SciShow Kids channel is filled with science videos, hosted by a "scientist" and her side-kick robot. Together they explain difficult science concepts so that elementary age kids can understand. New videos are uploaded to the SciShow Kids channel on Monday and Wednesday.
The videos offered by the SciShow Kids channel fall in to categories such as, Awesome Animals, Let's Go To Space, Science on the Playground, Watch it Grow, and various other categories. The information contained in the SciShow Kids videos is presented in a kid-friendly way.
Here is a a video found on the SciShow Kids channel in the Science on the Playground category.
SciShow Kids could be a great resource for your science classroom. I definitely suggest checking it out.