Comment by modeless

> In a conversational human context, saying it's made of rubber implies it's a rubber shell with air inside.

Disagree. It could easily be solid rubber. Also, it's not made of rubber, and the model didn't claim it was made of rubber either, so it's irrelevant.

> It floats because it's rubber [with air] as opposed to being a ceramic figurine or painted metal.

A ceramic figurine or painted metal in the same shape would float too. The claim that it floats because of the density of the material is false. It floats because the shape is hollow.

> It's not false to say a house is made of wood.

It's false to say a house is made of air simply because its shape contains air.