Here's why:
* Solid State: In ice, water molecules are tightly packed in a crystalline structure, held together by strong hydrogen bonds. This arrangement restricts their movement, making them vibrate only slightly around their fixed positions.
* Liquid State: In liquid water, the molecules have more freedom to move around, allowing them to slide past each other. This increased movement is why liquids can flow.
* Gaseous State: In water vapor, molecules are far apart and move rapidly in all directions. They collide with each other and the walls of their container, creating pressure.
Therefore, the state of matter where water molecules have the least movement is the solid state, or ice.
