In this perfectly timed photo we see Strokkur, a famous geyser in Iceland, on the verge of eruption. Located in the geothermal area beside the Hvítá River (in the southwest part of the country, east of Reykjavík), Strokkur erupts about every 4–8 minutes and can reach heights of 15–20 meters (50-65 ft), and sometimes even up to heights of 40 m (131 ft).

The frequency of eruptions coupled with a surrounding area of mud pools, fumaroles, algal deposits and other geysers makes the site a very popular tourist attraction.

A geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase (steam). The formation of geysers is due to particular hydrogeological conditions, which exist in only a few places on Earth. Generally all geyser field sites are located near active volcanic areas, and the geyser effect is due to the proximity of magma.

The water and vapour seen building up under the surface about to erupt is a good example of surface tension.