If you have math-able kids, it can be fun to play some guestimation games.
BBC via The Conversation via More or Less gets the order of magnitude on how much SARS-CoV2 there is out there from Christian Yates of U. Bath. His wife, who lives with the guy, suggested it's either a teaspoonful or a swimming pool, it usually is. They are Landmark Numbers, for positioning us in the world of quantity. Don't click on the link until you've given it a go with your 12 y.o. If you have a kid who is not math-able it's possibly because this sort of think-fest has been absent. Dau.II used to think that way, and probably still does because she's a fan of More or Less, Tim Harford and his books.
Guestimation is important for critical thinking because it forces you to lay out your assumptions and have a punt at the size of the numbers. Not precise numbers, but order-of-magnitude numbers. For the teaspoon or swimming pool SARS-CoV2 question you need to find out [roughly]:
- the number of infected people at any one time
- what are typical viral loads in human tissue
- do lung epithelia harbour more than kidneys?
- factor in the length of time infected - everbode kno that's 14 days
- maybe do something to note that viral load starts small and peaks at ~day6
- can we ignore viruses on surfaces and flying spittle?
- can we ignore reservoirs in bats and pangolins?