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Scientists Say: Geyser


Scientists Say: Geyser


Geyser (noun, “GUY-sir”)

Geysers are underground springs. On Earth, they are found near active volcanoes. The springs have narrow vents that open at the surface. Heat from below warms the underground water. At the surface, the water isn’t so hot. But it presses down on the hotter water below. That means the lower water can’t boil. It eventually becomes superheated — hotter than 100° Celsius (212° Fahrenheit). That ultrahot water rises up through the cooler water on top of it. As it rises, the pressure on the water lessens, so it starts to boil. That releases steam and hot water that spews through the vents at the surface. The result is a geyser that spurts up into the sky — sometimes for more than 42 meters (140 feet). That’s the maximum height of Old Faithful in Yellowstone National Park in the United States.

Geysers are rare. There are less than a thousand across the whole planet. And because geysers are only associated with active volcanoes, they are not distributed evenly. New Zealand, Russia and Chile have geysers, though. And Iceland is also known for its geysers. Iceland even has a geyser named the Great Geysir— which lends its name to all the other geysers around the world.

About half the world’s geysers can be found in Yellowstone National Park. There’s no flowing magma there, of course. But Yellowstone is the site of an active volcano. It just hasn’t erupted in hundreds of thousands of years.

In a sentence

The icy moon Enceladus also boasts warm geysers — warmth that might help support life.

Power Words

boil     To heat a liquid to the temperature at which it turns to vapor.

Enceladus     The sixth largest of Saturn’s more than 50 moons. Enceladus is bright white and covered with a thick shell of ice. Deep beneath that ice sits what appears to be a global ocean of salty liquid water. Enceladus is a round sphere, 500 kilometers (310 miles) across. It is a little less than one-third the width of Earth’s moon.

geyser     A vent (opening) in Earth’s surface that intermittently sends up a tall spray of steam or hot water. The sometimes explosive discharge of water and steam is propelled by the geothermal heating of water below ground.

Iceland     A largely arctic nation in the North Atlantic, sitting between Greenland and the western edge of Northern Europe. Its volcanic island was settled between the late 800s and 1100 by immigrants from Norway and Celtic lands (ones governed by the Scots and Irish). It is currently home to roughly a third of a million people.

magma     The molten rock that resides under Earth’s crust. When it erupts from a volcano, this material is referred to as lava.

moon     The natural satellite of any planet.

New Zealand     An island nation in the southwest Pacific Ocean, roughly 1,500 kilometers (some 900 miles) east of Australia. Its “mainland” — consisting of a North and South Island — is quite volcanically active. In addition, the country includes many far smaller offshore islands.

pressure     Force applied uniformly over a surface, measured as force per unit of area.

vent     (n.) An opening through which gases or liquids can escape. (v.) To free gases or liquids that had been under pressure. The term can also be used to release strong, pent-up emotions, such as anger.