When I've helped teach D3 it's always hard to get some of the basic concepts of joins and scales locked in. Mike gives a thorough overview of what is going on (and this is still an introduction) it's hard to teach when to choose what type of scale for people that might have forgotten some of their math lingo.
I've had some success in (maybe wrongly) demonstrating scales with mapping temperature in Farenheit and Celsius and how the scale is drawn if the domain and range are both 0-100 vs a scale of 0-100 and a domain of 32-212.
Curious if anyone else has any examples that help demonstrate some of these concepts based on their experiences!
With the COVID-19 pandemic, the topic of log scales has even made its way into The New York Times as people try to wrap their heads around exponential growth.
(Perhaps mods can combine the two posts?)