How is volume calibration typically done?

Hi, I didn't see this topic come up when I did a search, but how is a volume calibration typically done, such as for a laboratory automatic pipettor?
Also how is volume calibration usually done for larger volumes, such as a 5-gallon bucket? Currently we have a stick with markings on the side that we have calibrated to correspond to specific volumes due to the height of the liquid in the bucket.

Thank you in advance for any insights,

Matthew

In regard to buckets of the volume you mention, I would suggest that this could be done not volumetrically but gravametrically. This means placing the container on a certified calibrated scales and filling it until the scales indicates the target volume. It is easier for me to talk in litres and kilograms...

I Kg of water at STP (Standard Temperature and Pressure) equals 1 Litre of water (0.264172 US Gal). You can fill the container and then check the mark. Keep a record of the check. I am not saying this is absolute but there is a little science behind it. If the container is used to measure out a specific quantity of a liquid other than water then you will need to take account of the density/specific gravity of the liquid in the calculation.

For calibration of volumetric glassware which usually operates to tighter tolerances you will need a little more science. This document should help you out with both of the above methods.

George