I'm not familiar with that particular series, but our 5 and 7 year-olds watch a wide variety of science and history shows intended for all ages. A lot of it goes over their heads, but they generally enjoy them and ask good questions that show a certain understanding.
For example, we recently watched an adult-targeted documentary on the atomic bombs at Hiroshima and Nagasaki. They didn't understand the larger context, but they learned where Japan was on a map, they learned a little about war, and they learned that the bombs were horrible but ended a war that was horrible.
My kids are not geniuses. Their attention is as fickle as any child's, moreso in the case of my son. They usually prefer shows about princesses or super heroes. There are a few things we do to get them interested in these kinds of shows:
- Show them regularly, a few times a week at least. The kids should see it as a normal occurrence instead of something strange and new you're forcing on them.
- Show them right before bed, when they are already winding down for the day, a little bit bored, and looking for more passive entertainment.
- Recognize topics the kids bring up, and choose shows that elaborate on those topics. Kids ask a lot of questions out of the blue. For example, we were shopping yesterday and my son suddenly wondered how many different animals there were in the world. That's a good opportunity to present a nature show about the many species in rain forests, for example.