Question

Which would be less dense, a feather or a sponge?

Answer 1

Feather.

Answer 2

Feathers float whereas sponges sink.

Answer 3

Feather because it's mass, volume and density is way less than a sponge. However, @kingwalkr you are not incorrect about floatation. Both will float, but how they are put or lied on top of water does change for bothe.