Why do pipes burst in the winter?
Most solids and liquids expand with rising temperature. Water, the most common and most important liquid on Earth, has a limitation on this expansion. Ice water that is at a temperature of 0oC or 32oF will contract when it is heated. This contraction continues until after an increase beyond 4oC or 39.2oF. Then water that continues to be heated will finally begin to expand like other liquids until it reaches a gaseous state. At 4oC water has its smallest volume and also its greatest density. Water that is below 0oC has a larger volume and a smaller density. Therefore the reason why ice floats in your cup of soda is because ice is less dense or weighs less than water. This is also the reason why your water pipes may burst in the winter if you are not careful – the water inside increases in volume and weight as it cools from 4 to 0oCelsius.