I've seen two of the six-episode "Elements" subsections so far, both made in the 2000s: Elements Chemistry and Elements Biology.
They're an excellent way to get a brief summary of the subject's basics. I've tried out some other short series for this purpose, but those are often bloated, boring, and, what's worse, - uninformative, leaving you frustrated and unenlightened.
Assignment Discovery is different. Take Chemistry: they give you 6 episodes. They spend the first 10-15 minutes of the episode giving you a very clear, graphically great, illuminating primer on an aspect of chemistry: the periodic table, acids and bases, hydrocarbons. They play some suitable music - bouncy but unobtrusive - in the background, and the narrators - one male, one female - switch between segments. You don't actually see them, which is a refreshing change from annoying, in-your-face narrators with their lame-looking enthusiasm. AD is made in a way that's perfect for people with concentration problems - it relaxes you into learning.
The rest of each episode will proceed in a completely different vein, and a more BBC-ish style, leisurely telling you about how the subject is topical to our lives, usually - to modern technology. You can watch that part, or you can immediately skip to the next episode and get the next condensed-info 15-minute segment from its beginning. That's what I did. Consequently, you can catch up on chemistry in a little over an hour, maybe a little longer if you're gonna take notes and/or pause to look the issue up on the Web. I had to do a couple of such searches, but mostly the presentation of the material was extremely comprehensible.