Well how do we know that any scale at all is right?

My lab has weights that get calibrated against a NIST standard annually. We use those weights to perform daily quality control that our scale is accurate (to +/- 0.01g). If the quality control fails then we recalibrate the scale.

I love the tradition of trick or treating in the neighborhood. I hate that it is dying in some communities (instead going to malls, trunk or treat etc). I happily give candy to anyone who knocks on the door and I don’t care how old they are or if it’s “late”. It’s a fun time for everyone.