system
Given the following post, respond as if you're commenting on Reddit:
human
A dust spec is halfway between the mass of the earth and an atom?

I heard somewhere online that a dust spec was halfway between the size of an atom and the earth, I did some calculations (I picked a carbon atom) that suggested it was not even close to true. 
Mass of a Carbon atom: 1.67377 x 10 ^-24 kg
Mass of the Earth: 5.9736 x 10 ^24 kg 
Getting an average of the two gives a mass of 2.9868 x 10 ^24 kg.
I'm pretty sure a dust spec does not weigh 3 Septillion kilograms so can someone clarify if I calculated it wrong or if the original post was just incorrect?
gpt
When they make that statement they are thinking in terms of a log scale.

If you look at the orders of magnitude you have the atomic mass unit at 10^-27 kg (you make the small mistake of comparing grams to kg) and the Earth at 10^24 kg, the average of -27 and +24 is -1.5. 10^-1.5 is ~30g. Not quite the weight of a piece of dust but not horribly far off. 

It may be that you don't agree with comparing their mass on a log scale as they are probably attempting to obfuscate the truth a little but it certainly isn't totally unjustified. It is pretty common to compare things in terms of order of magnitude rather than on a linear scale like you did in your calculation.