Some natural fountains sometimes spray water and sometimes are silent without water. They are called "geysers". Geysers are hot springs, and the water is hot. Compared with ordinary hot springs, geysers are not common. Yellowstone Park in the United States is the place with the largest distribution and concentration of geysers in the world. In addition, geysers have also been found in Iceland, New Zealand, the Andes of South America and Tibet, China.
Geysers usually erupt at intervals of several hours to a few minutes. When erupting, first there is a rumbling roar under the spring, and then white steam and hot water emerge from the spring mouth. The water flow will spray higher and higher until it reaches the peak, then the water potential weakens until it disappears, and the ground exposes the spring mouth again.
The eruption of geysers is always impressive. For example, there is a famous geyser "old faithful spring" in Yellowstone Park in the United States. It erupts every hour or so. The maximum water column can reach 45 meters. The hot water gushes out with a large amount of white steam, and sometimes there are rainbows. The scene is very spectacular.
Why does geyser water not flow out slowly like ordinary spring water, but erupt and stop for a while? If you want to know the answer, you have to go deep underground and explore the internal structure of geysers. Geysers have complex structures, mainly including several parts: water supply, circulation system and heating system.
There is geothermal energy under geysers. When groundwater meets high-temperature rocks or magma underground, it will be heated quickly, and sometimes the water temperature will even exceed 100 ℃. However, due to the narrow and tortuous spring channel and full of water, the hot water and steam at the bottom can not flow upward for a while. Geothermal constantly heats the groundwater, and the energy of hot water is also increasing. When the hot water and hot gas reach a certain pressure and eventually exceed the pressure of the water column in the channel, the underground hot water and hot gas will push all the water in the channel out of the ground, resulting in a large eruption of spring water. After the water in the channel erupts, the bottom pressure is released and the eruption stops. At this time, the groundwater will be replenished into the channel of the geyser again and enter the process of heating and pressurization again until the next eruption.