Crash Course Kids and SciShow Kids.
Crash Course Kids and SciShow Kids use the same format as their older counterparts. They provide a broad overview of various topics through the use of greenscreen visuals and a lot of talking. The ones that I've watched so far are still a bit too fast-paced for my liking so your students might have to watch them a second time and or pause them to digest the content as they go. I've embedded a video from each channel below.