for a short clip of water dropping from a faucet. The image consists of 18 individual images, out of a series of approximately 300 images. The surface tension of the water inside the faucet holds the drop in and is responsible for the elongated shape at the beginning. Once pressure or gravity forces the drop free, and it falls, surface tension forces it into its spherical shape.
See http://www.chemguide.co.uk/atoms/bonding/hbond.html --
The animation is not a series of the same drop, but different pictures of different drops arranged to make them look like a series of pictures of one drop.