Did you know? Water expands when it freezes.

 Water expands when freezing

Have  you ever wondered why ice cubes float in your lemonade? If you think  that’s because water is special, then you are right. Despite most  substances shrinking as they get colder, water has a pretty strange  behavior, as it reaches its maximum density at 4 degrees Celsius. As it  goes below that temperature and it starts to freeze, water expands its  volume by up to 9%. This happens because water molecules are connected through something called hydrogen bonds,  which is something that most substances don’t have. When water goes  below the 4 degrees threshold, these bonds arrange the molecules in  beautiful hexagonal structures, increasing the space between them. The fact the ice floats on water is really good news, since otherwise we would have no Antarctica, polar bears or Titanic movie. 

Here is a nice explanation of how that happens