Question

Using 3 – 4 sentences explain (in your own words) why water expands when it freezes?

Answer 1

Water has this unusual behavior when cooled at 4 degrees Celsius; it expands slightly until it reaches the freezing point and continue to expand by approximately 9%. This characteristic has something to do with the structure of the water molecule where there is a strong tendency to form a network of hydrogen bonds and each hydrogen atom is in a line between two oxygen atoms. These bonds force the crystalline structure to be very open into hexagonal form and expand dramatically.

Answer 2

Answer:

In the case of water, that is, when the liquid water gets cooled, it gets contract to a temperature of about 4 degrees is attained. However, after that, it starts to expand somewhat till it moves towards the freezing point, and eventually when it freezes, it expands by about 9 percent.  

This characteristic has its source in the composition of the water molecule. In water, there possesses a capacity to produce a network of hydrogen bonds, where each atom of hydrogen is in a line amongst the two atoms of oxygen. This tendency of hydrogen bonding gets robust as the temperature lowers down. The formed ice structure is completely hydrogen-bonded and these bonds permit the structure to get open, thus, expansion takes place.