"One Billion Infected In 81 Days?" - Explaining Exponential Growth & Epidemics

While China is 'recovering' (according to its 'official' numbers), the rest of the world is escalating aggressively in terms of the exponential growth in Covid-19 cases (and sadly, deaths).

How bad can it get if the rest of the world does not go full-China in terms of authoritarian crackdowns?

Given the current rate of expansion - and assuming exponential growth - the virus could infect one billion people within 81 days (up over age around 10x every 16 days).

But as Stanford grad Grant Sanderson lays out in great detail and simplicity, it doesn't work that way as what really happens is a 'logistic curve' as opposed to an exponential curve...

While this video uses Covid-19 as a motivating example, the main goal is simply a math lesson on exponentials and logistic curves. The following video is more focused on Co-19 itself: