Pennies

The Scientific Method

Observation

There are some pretty nasty looking pennies in circulation...and there are some very shinny pennies in circulation.

Question

I wonder if the mass of a penny changes over it lifetime?

Hypothesis

A: An older penny appears to be dirty, so the mass would increase over its lifetime making them heavier.

B: An older penny would be worn down as it rolls around in a pocket, so the mass would decrease over its lifetime making them lighter. Hypothesis

C:?