A 12-oz can of regular soda will sink in the same container of water in which the same brand of diet soda floats. Brand is not a factor, and only in the case of 12-oz aluminum cans does the small density difference straddle the density of water. All plastic containers sink.

Do Coke cans sink?

While both beverages contain mostly water, the regular Coke has a lot of sugar (or dense corn syrup) dissolved in it—roughly 39 grams per can. This makes the density of the Coke liquid greater than that of pure water, so the regular Coke sinks.

Does aluminum can float?

The material that an object is made of will dictate whether it will sink or float. Aluminum and clear plastic are denser materials and they sink, while wood and milky plastic are less dense and float.