I feel like most of these comments have ignored the article. They were taught how to read clocks, in first and second grade. Then they had no need of the skill for most of a decade and it atrophied. I suspect many would struggle to remember some of the things we had down well in elementary school, like writing fully in cursive, knowing the difference between types of rocks and clouds, or giving some full speech you had to memorize at the time (it was Patrick Henry's "Give Me Liberty" speech for me). And if you're someone who does know the difference between your cumulonimbus, cirrocumulus and such, rad! But do you suspect most of your peers remember?

I think the better question is, and the article poses this, why are students not bothering to refresh the skill now that it's necessary again?