The fantastic shapes and patterns you can see in this exhibit are largely due to the strong cohesive forces between water molecules, also known as surface tension.
Water molecules are polar, that is, the electric charges within them are arranged so that each molecule has a positive and a negative side. This polarity makes water molecules tend to stick strongly to one another, causing water droplets to form spheres and water surfaces to ripple as if covered in a skin of fabric.
Harold Edgerton, Milk Drop Coronet. Photo: 1957, © 2010 MIT. Courtesy of MIT Museum. (click image to enlarge)