Item floats, but density isn't less than water

Question

The mass of my film canister filled with sand is 39.35g. The volume is 25.74 cm cubed. What would the density be? And why did it float?

Answer 1

Since density is expressed as mass/volume, the density of your item would be

39.35 g/25.74 cm³ = 1.529 g/cm³

Why did it float? It shouldn't float because its density is greater than that of water. But if it were more buoyant, then it might float. Like a large ship or tanker. Since it is filled with sand, it might depend on the nature of the sand. If it were extremely fine, then there would be a lot of air in the canister, and this would allow the entire object to float. Again, analogous to a ship in water.