Chemistry Imagine what would happen if ice cubes would sink to the bottom of drinks – The Arctic ocean would not be covered in ice – and that would have profound effects on climate and in fact entire marine life. The molecular structure of water molecules is just right for the molecules to form a very open array so that ice actually occupies a slightly larger volume of water than the same amount of liquid water. So ice is less dense than water and floats on water. It is this open structure of water molecules, with plenty of space between atoms and the regular pattern of lattice array that is responsible for example, for the beautiful, regular geometry of the pattern of a snow flake. We are different from a blade of grass or a dolphin because the sequence of bases in your DNA is different from the sequence in theirs. DNA is a molecule, which carries the code of life. The basics of chemistry are incredibly simple, but the complexity of the molecules that can be built in accordance with simple rules is astonishing.