Question
Question: Explain this picture in your own words. 
Solution
As we can clearly see the difference in the crevice or crack filled with water in both the images. Image ‘a’ has a crack filled with water in liquid phase whereas image ‘b’ simply represents ice filled in it with different length and width of crack. So we have to explain the reason behind the difference in the dimensions of crack or crevice of both the images.
Complete answer:
Let us discuss water and its varying properties in different states.
-Water: It is the most vital substance present on earth which is necessary for the survival of life. It shows quite different properties compared to other liquid substances. Its chemical formula is H2O. It is a polar solvent and dissolves most of the chemical compounds easily.
-We know that when water molecules are in the liquid phase, hydrogen bonds between the molecules are continuously being formed and reformed in a random fashion. The average amount of hydrogen bonds formed by a single water molecule is 3.4 bonds at 25∘C.
-When water molecules freeze by losing energy, they do not vibrate or move vigorously which allows more stable hydrogen bonds to form between water molecules because there is less energy in order to break the bonds. Now the average hydrogen bonds per water molecule are 4 bonds.
-The hydrogen bonds are formed in an orderly, crystalline way that causes density to decrease as each water molecule is held away from its neighbors at an equal distance much alike to the length of the hydrogen bonds. This is the reason behind expansion of water as it freezes.
-So when the water in the crevice of image ‘a’ changed into ice by freezing, it simply expanded the crevice which brought changes in its overall dimension as shown in image ‘b’.
Note:
-Remember that the crystalline arrangement of water molecules is less dense than that of the molecules in liquid form due to which ice is less dense than the liquid water. This property can be easily noticed as icebergs float on huge water bodies.