Monty fully filled a glass bottle with water, put a stopper on it and placed it upright in the freezer overnight. When he looked at it in the morning, the stopper was out of the bottle and a column of ice had emerged through the opening of the bottle.
Which one of the following is the best explanation for what Monty had observed?

Answer: D. The volume of water had increased when the water froze, forcing the stopper out of the bottle and forming the column of ice.

Water expands (increase in volume) upon freezing. This is due to the fact that upon freezing, water molecules crystallize into an open hexagonal lattice form in which molecules enclose more space among themselves than in the liquid state. Thus, in the given case, volume of water increased when the water froze, forcing the stopper out of the bottle and forming the column of ice.

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