The molecules of water are bunched together most closely in the solid state, which is ice.

Here's why:

* Solid: In ice, the water molecules are locked in a rigid, crystalline structure with strong hydrogen bonds holding them in place. This close arrangement makes ice less dense than liquid water, which is why ice floats.

* Liquid: In liquid water, the molecules are still close together but can move around more freely than in ice.

* Gas: In water vapor (the gaseous state), the molecules are far apart and move independently.