"Heavier" Milk

Since there is air in milk containers, milk will slosh inside the carton when moved. Frozen milk won’t slosh, which would certainly affect how it feels when the container is handled. Its inertia would be completely different, making it feel “more massive,” which could be described as “heavier.”

ETA: Link to column - http://www.straightdope.com/columns/read/423/is-frozen-milk-heavier-than-liquid-milk

Yeah, we were just talking about that over here.
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