Is a 100 kg Cotton Bag Heavier than a 100 kg Iron Bar?

[DrChem]

you have a bag of cotton and an iron bar, each indicating a mass of 100 kg when measured on a weighing machine. in reality, one is heavier than the other. can you say which one is heavier and why?

 

[cesiumfrog]

Is there an atmosphere permeating the weighing machine?

 

[TVP45]

"can you say which one is heavier and why? "

If I were using a NIST traceable weighing machine, I'd use the standard correction for the effect you're thinking of and neither would be heavier.