How geysers work

Image 1. A view of Castle geyser, in the Upper Geyser Basin of Yellowstone National Park, in 2003. When it was named in 1870,

the rocks around the geyser looked like the towers of a castle. Photo by: Greg Willis/Wikimedia

First, take all of the water from a swimming pool. Next, put it under tons of pressure. Finally, shoot

it hundreds of feet in the air. Geysers erupt like this every day.

A geyser is a shaft, or hole, in the Earth that can go down miles. When pressure builds up, it

shoots out hot water and steam. It works like a teapot that boils up until steam causes the whistle.

There are some pretty famous geysers, like Old Faithful in Yellowstone National Park in

Wyoming.

Still, they are among the rarest natural wonders on Earth. There are only about 1,000 active

geysers on the planet. They can be found in places like Iceland, New Zealand, Chile and the

United States that are known to have had volcanoes. They all have one thing in common: a high

level of geothermal activity. Geothermal energy is heat inside the Earth, which can also cause

volcanoes, earthquakes and hot springs.

By How Stuff Works, adapted by Newsela staff on 05.06.18

Word Count 810

Level 850L

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In this article, we'll explore how geysers are formed. We'll also look at how they erupt and what

makes them so unique.

How Geysers Form And Erupt

Geysers need three things. They need heat, water and a natural underground plumbing system to

hold the water as it is heating up.

Many geysers get their water from nearby rivers. Others depend on rain and snow miles beneath

the ground.

A geyser is made out of cracks in the Earth. They start at the geyser's mouth on the Earth's

surface and run miles down. Some geysers are one long hole in the ground, while others connect

to large pockets of water underground. Geysers are under huge amounts of pressure and can't

have any cracks in them that would let water or steam escape.

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The water in geysers is heated by magma. This super-heated liquid rock lies around 3 miles

beneath the Earth. Many geysers are located on the edges of the Earth's tectonic plates. These

are moving plates of rock, which makes up the Earth's crust. When they rub up against each

other, they can cause earthquakes and volcanoes, and also create heat for geysers.

How Do Geysers Erupt?

Water moves into the geyser through cracks in the ground. At the bottom of the geyser, magma

heats up the water. Eventually, some of the water begins to boil. The boiling water pushes up a

small amount of water through the Earth and out of the opening. There is more room down below

and the pressure goes down. Less pressure on liquids helps the molecules escape and become

steam. The steam quickly expands and pushes water and steam up and out the mouth of the

geyser. Eventually, the entire system will either run out of water or the water will cool down and

the eruption will stop. Then the cycle starts all over again.

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Cold Geysers

While most geysers are hot enough to burn you, cold-water geysers are a different story. These

geysers are caused by water that contains carbon dioxide, which is a gas. Sometimes, the

pressure goes down. Then, carbon dioxide bubbles in the water grow larger and push water out.

Exploring The World's Most Famous Geysers

• Geysir: This geyser is located in Iceland. It was discovered in 1294, making the Geysir the

oldest known geyser on the planet.

• Old Faithful: Old Faithful in Yellowstone National Park is probably the most famous geyser on

Earth. Old Faithful is famous for its 100- to 180-foot high eruptions. The eruptions are also very

frequent, which is how it got its name.

• Waimangu Geyser: The highest eruption of all time took place at this geyser in New Zealand. In

1902, the geyser shot water about 1,475 feet into the air.

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What's With The Name?

The word "geyser" is named after Geysir, the first geyser ever discovered. Geysir comes from the

Icelandic word "gjósa," which means "to gush."

Human Interaction With Geysers

Geysers are pretty spectacular. People will travel far distances to see one erupt. Parks often keep

tourists from getting too close. People can harm geysers by throwing trash in them. Geysers are

extremely hot and can harm tourists as well.

People can use the energy from geysers to make electricity. However, it can drain the geyser of

water or energy.

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Quiz

1 Examine Image 2 and read the selection from the section "How Geysers Form And Erupt."

They start at the geyser's mouth on the Earth's surface and run milesdown. Some geysers are one long hole in the ground, while othersconnect to large pockets of water underground.

HOW does the image support the information in the selection above?

(A) It shows that hot springs are usually near geysers.

(B) It shows how many miles geysers can erupt into the sky.

(C) It shows that glacial gravel surrounds water under geysers.

(D) It shows pockets of water beneath the mouth of the geyser.

2 Use Images 1, 3 and 4 and information from the article to select the TRUE statement.

(A) Geysers always create a rainbow when they erupt.

(B) Geysers spread ice and snow onto the surrounding land.

(C) Geysers shoot hot water and steam high into the sky.

(D) Geysers are very safe and cannot harm tourists.

3 Read the selection from the section "How Do Geysers Erupt?"

The boiling water pushes up a small amount of water through the Earthand out of the opening. There is more room down below and the pressuregoes down. Less pressure on liquids helps the molecules escape andbecome steam.

What does the word "molecules" refer to?

(A) tiny particles of water

(B) openings in the Earth

(C) pressure placed on liquid

(D) heat underneath the surface

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4 Read the selection from the section "Exploring The World's Most Famous Geysers."

Old Faithful in Yellowstone National Park is probably the most famousgeyser on Earth. Old Faithful is famous for its 100- to 180-foot-higheruptions. The eruptions are also very frequent, which is how it got itsname.

What is the BEST definition of "frequent" based on the information above?

(A) bland and boring

(B) powerful and rare

(C) regular and reliable

(D) constant and worrisome

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