Fact 1: When water freezes , that water expands.

Fact 2: Water pipes can freeze and burst.

Given the two facts above, answer the question "Why do pipes sometimes burst during the winter" with the following options: 
- Water evaporating
 - flooding
 - Water expanding
 - energy usage
 - Water melting
 - Water contracting
 - colder weather
 - massive damage


 

   Water expanding      