Question: Why does ice sink in heavy water?

Michelle Valkanas answered on 14 Mar 2019:

I may be wrong, but I do not believe regular ice sinks in heavy water. Heavy water ice cubes sinks in regular water though! It all comes down to density. Density is defined by how much stuff (atoms) are in one space. The more dense items sink (i.e. the higher the density) and the less dense items float. Here is the density of water, ice, heavy water, and heavy ice.
water = 1 g/cm^3
ice = 0.92 g/ cm^3
heavy water = 1.11 g/cm^3
heavy water ice =1.105 g/ cm^3

Therefore, regular ice floats in both water and heavy water because it is less dense. Heavy water ice is denser than regular water and so it will sink. Thank you for such a fun question!