MCQ Detailed View

When water is placed inside a closed bottle and allowed to freeze, it often causes the bottle to crack or break. This happens because water exhibits a unique property — it expands when it freezes. Most substances contract when they change from liquid to solid, but water behaves differently due to its molecular structure.

Water molecules are arranged loosely in the liquid state. As the temperature drops below 4°C and approaches 0°C, the molecules begin to form a crystalline solid structure known as ice. In this solid state, the molecules organize in a hexagonal pattern with more empty space between them. As a result, the volume of water increases as it turns to ice, even though the mass stays the same.

This expansion increases the pressure inside the sealed container. If the bottle is made of rigid material like glass or hard plastic, it cannot stretch or absorb the internal pressure. As a result, the walls of the bottle are forced outward by the expanding ice until they crack or break. This is why freezing water in sealed bottles or pipes can be dangerous in cold weather.

Let’s break down the options:

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  Option A is correct because water expands upon freezing.

  
  


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  Option B is incorrect — bottles may contract slightly in cold, but this is not the cause of breakage.

  
  


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  Option C is misleading — while the outside may be colder, that is not the primary reason the bottle breaks.

  
  


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  Option D is wrong because option A correctly explains the phenomenon.

  
  

This concept is a core part of Physics and is related to the properties of matter, thermal expansion, and anomalous behavior of water.

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