Surface tension. Dandelion seeds supported by the surface tension of water. This effect is caused by the attraction between the molecules of water. This attraction is random inside a body of water, but at the surface the attraction is not random; the surface water molecules are attracted more strongly to other water molecules than to the air molecules. The surface water molecules align themselves to form an ordered layer that acts as a 'skin'. The spokes of the dandelion seeds are seen causing small dimples in this 'skin'. The tension of this surface layer can only support a certain weight, and it would collapse under anything much heavier than dandelion seeds.