Here, a stream of water is pumped up through a bed of sand. In fitful spurts, the water bursts from the sand in a meandering eruption that never settles in one place. Sand may seem solid enough when you walk on it at the beach, but sand with water flowing through it can become a heavy liquid. Natural springs that well up through sand look a lot like what you see here. Some ranchers put a box-called a spring box-over the top of their natural springs to protect them from being muddied and clogged by trampling cattle.
© The Exploratorium, 1996