Generally, solids are denser than their liquid forms. Here's why:

* Packing: Molecules in a solid are tightly packed together in a regular, crystalline structure. This means they are closer to each other than in a liquid.

* Movement: Molecules in a liquid are able to move around more freely compared to a solid. This allows them to spread out more, resulting in a lower density.

Exception: Water is a well-known exception. Ice (solid water) is less dense than liquid water. This is due to the unique hydrogen bonding structure of water molecules in ice.

In summary: While there are exceptions like water, it is generally true that solids are denser than their liquid forms.