A diagram of a 2-compartment refrigerator is shown. A molecular depiction of the water in the ice tray is also shown. Space-filling models representing water molecules are depicted wherein 1 large sphere represents 1 oxygen atom and 2 small spheres represent hydrogen atoms in each molecule. Water molecules are interspersed irregularly and connected to the adjacent water molecules through 2 to 3 hydrogen bonds represented by dotted lines. The water molecules vibrate slightly.
If the temperature drops below about 0°C (the freezing point), water changes from a liquid to a crystalline solid (ice). With too little energy to break hydrogen bonds very often, each water molecule forms four hydrogen bonds that pull the molecules into a regular arrangement (a lattice). Click on the ice tray to see the change when water freezes.