This really is a funny story. I'm most amused that Brian is now weighing all his dumbbells. I wonder how many of them are off?

What are the dumbbells made of? It occurs to me that if a company used a particular metal alloy, and then that alloy wasn't available, a person who didn't know much about metals could order another one with a similar name ("it said steel!"), but the different composition would give it a different density. So the people making the dumbbells would use the same physical quantity of metal inside the weight, but the mass would be different.