Suppose I am working on a problem and I wish to calculate the density of something. I measure the mass to be *m* = 24.5 grams and the volume is *V* = 10 cm³. In this case the density would be:

ALERT! ALERT! ALERT! This is not a test!!!! Something is drastically wrong! Clearly I messed up. How can I have the mass measured to **3** significant figures, the volume measured to **1** significant figure, but the density calculated to **3** significant figures? Isn’t this a violation of some fundamental principle that could be worse than the Large Hardron Collider coming online and destroying the world?

No, we can all calm down. This really isn’t a big deal. Unfortunately many people (*hint* like chemists) do get all freaky about significant figures. Now calm down chemists. I am not saying significant figures are entirely stupid. They do have a purpose. What I AM saying is that they are not some fundamental rule that can not be broken.

So what is the deal with significant figures?

Continue reading “Significant figures what are they for and what do they have to do with uncertainty?” →