Wait a 747? Isn’t the current Air Force 1 already a 747? I thought it’d at least be a chonky A380 or something.

By that definition, it can’t be exactly 7 then either. 10^-7 is just an estimate that we’ve agreed works fine. To my knowledge we haven’t really tried to improve this accuracy either?

Also I’m pretty sure it’s only coincidentally 7. The calculation for pH isn’t based on any property of water.