@Vitaly,
Love the enhancements! Especially the TimeLinePlot with labels, I will have to show that to my daughter. It looks like Parallelize cuts the computation time by ~75%, gotta remember to use that in the future too.
Lots of reasons for using Wolfram with my child, especially for this type of exploration. The first is that I have fun with this and it's important to connect with your kid through hobbies (same reason I teach my kid skiing).
But beyond that, Wolfram is incredibly accessible. The functions are very human-readable, even for a kid (MoonPhase[] gives you the phase of the moon!). The built in knowledge makes it easy to focus on the fun part of the exploration rather than data collection/cleaning/loading.
At a higher level the Wolfram Programming Lab is an easy and powerful coding environment. The EIWL course is perfect for self-directed learning, having a video, scratchpad, questions/coding, documentation and lesson text all in one browser window. I can tell my kid to get started on her lesson for the day and she's actually learning within a few clicks.