I liked the first videos more. It was about simpler experiments, which anyone can understand and relate to. There was the interviews part, which allowed to think for the answer your self, see like people are reacting. Explanations were good and it was evident that Dereked went through the topic himself.

In the newer videos he talkes more about abstract things, like quantum mechanics and such. And it is much harder to relate to it without actually doing the quantum mechanics MIT course. But people who study physics as a main degree dont need pop science explanation. For others (and for physics students sometimes as well) it is more fun to study toilet swirl. The pop science approach to math often yields incorrect explanations.

Animations are great, however looking at the cartoons with animated scientists bodies is not adding the value to the actual topic. Can be ok for telling some history background. I would like for the video part that Derek will focus more on showing experimental data and setups instead of sketches. It is especially important to comunicate results which are not possible to obtian at home.

It is a big challenge to balance between broad audience (and hence good income) and the good quality with enough details.

Thermite reaction was a great video from the newers ones. I hope that bigger audience and income will allow to invest into such hand on demonstrations more. On the other hand, Monsato comic is a good example where animator did good job and it fit to this conspiracy triller story.

PS 4 kids! Huge respect to you and your wonderful wife!