Title text:
Highway engineers like Planck units because, like the speed of light, the energy capacity of a typical car's gas tank is 1.
Transcript:
Transcript will show once it’s been added to explainxkcd.com
Source: https://xkcd.com/3289/
I like doing a little magic trick when I have to guesstimate base 10 logarithm of a number by looking at its length. It feels like I'm doing something wrong and yet it works.