Estimations: Your Breath and Julius Caesar"s

Not all of physics consists of pin-point accurate mathematics. In certain situations, using assumptions and rough values to come to a workable value is very important. Other times, we may not have the time to run through a very precise set of calculations, and we need a quick estimation. Now please be aware that estimations and educated guesses are NOT the same thing.

An educated guess is throwing out a (seemingly) random number using some vague thought process based on prior knowledge. In an estimation, you use generalised values and rounded figures to work out your final answer. This will, of course, make the final solution fundamentally inaccurate, but it won’t be totally unreliable - and that is why estimations are incredibly useful. One of the most popular estimations involves choosing a famous historical figure and calculating how many molecules you’re breathing in -- right now -- that were in their last breath.

So let’s have a go with Julius Ceasar...
http://www.fromquarkstoquasars.com/estimating-how-many-molecules-you-breathe-that-were-from-julius-caesars-last-breath/

Image: Andrew Bossi via WikiMedia