Answer:
When liquid water is cooled, it contracts until a temperature of approximately 4 degrees Celsius is reached. After that, it expands slightly until it reaches the freezing point, and then when it freezes it expands by approximately 9%. When water freezes, water molecules form a crystalline structure maintained by hydrogen bonding. Ice is less dense than water because the orientation of hydrogen bonds causes molecules to push farther apart, which lowers the density.