Water on Earth By National Geographic Society, adapted by Newsela staff on 03.27.19 Word Count 657 Level 640L

Image 1. A blueish glacier is seen in an ocean in Antarctica in February 2019. Most of the freshwater on Earth exists in the form of glaciers. Photo by: Ozge Elif Kizil/Anadolu Agency/Getty Images

On Earth, water moves through the land, oceans and air. This is called the water cycle. Water always exists in all three places, in many forms. It is in lakes, glaciers, underground and in clouds.

Evaporation, Condensation And Precipitation

The water cycle is made up of three major parts: evaporation, condensation and precipitation.

Evaporation

Evaporation is when a liquid changes to a gas. A liquid is something that flows, like water in a river. It is not hard like a rock. A rock is a solid. In the water cycle, liquid water in the ocean, lakes or rivers evaporates and becomes water vapor. Water vapor is a gas that you cannot see. It goes up into the air into the

This article is available at 5 reading levels at https://newsela.com. atmosphere. The Earth is surrounded by a cloud of gases called the atmosphere.

Evaporation is driven by the sun. The sun warms up the water on the surface of the ocean. The tiny parts that make up water start moving around quickly and spread apart. The water turns into a gas.

Condensation

Condensation is when gas changes to a liquid. This happens to water vapor in the atmosphere. The tiny parts of water vapor that were once warm and moving apart become cooler and move closer together. This causes the vapor to become liquid. Clouds can form during condensation.

Precipitation

Precipitation is a liquid or solid that falls to Earth. It falls after condensation happens in the atmosphere. Rain and snow are precipitation.

Precipitation is important in the water cycle. It is how water moves from the atmosphere to the Earth or ocean.

States Of Water

Through the water cycle, water continually rotates through three states: solid, liquid and vapor.

Ice is solid water. It is hard like a rock and does not flow. Most of Earth's freshwater is ice, locked in giant mountains of ice called glaciers. They are mainly found in the North and South Poles.

When ice melts it turns into a liquid. The ocean, lakes and rivers hold liquid water, and it is also underground.

The amount of water vapor in the atmosphere is different across Earth. There is a lot of water vapor in the air above the ocean. Very little vapor is above deserts because it is dry.

The Water Cycle And Climate

The water cycle has a big effect on Earth's climate. Climate is what we call the weather that happens in an area. Humidity is one part of weather that affects climate.

Humidity is the amount of water vapor in the air. Some places have higher humidity than others. This is why there are very different climates on Earth. Think of islands or coastal areas, like Florida or Hawaii. These places are usually very humid. Water vapor makes up a large part of the atmosphere in these areas. Places with deserts, like Arizona, are not humid at all.

The Water Cycle And The Landscape

The water cycle also affects the shape of the Earth's surface.

As glaciers slowly grow, they can carve away entire valleys. They can also create mountains. Glaciers can push together and squeeze up the earth between them.

Glaciers can make giant lakes, too. The Great Lakes are found in between the United States and Canada. They were created when glaciers carved huge bowls into the land. Then enormous sheets of ice melted and filled the bowls.

This article is available at 5 reading levels at https://newsela.com. Erosion is when water wears away part of the land. The flow of water can carve huge canyons, like the Grand Canyon.

Fast Facts:

Breaking The Cycle

The water cycle can change. Glaciers can melt faster than their ice can be replaced by precipitation. This is called glacial retreat. Glacial retreat limits the amount of fresh water that exists on Earth. That is happening now faster than it ever has before.

This article is available at 5 reading levels at https://newsela.com. Quiz

1 Which selection from the article helps the reader understand HOW the water cycle affects the weather?

(A) On Earth, water moves through the land, oceans and air. This is called the water cycle. Water always exists in all three places, in many forms. It is in lakes, glaciers, underground and in clouds.

(B) Ice is solid water. It is hard like a rock and does not flow. Most of Earth's freshwater is ice, locked in giant mountains of ice called glaciers. They are mainly found in the North and South Poles.

(C) Think of islands or coastal areas, like Florida or Hawaii. These places are usually very humid. Water vapor makes up a large part of the atmosphere in these areas.

(D) The water cycle also affects the shape of the Earth's surface. As glaciers slowly grow, they can carve away entire valleys. They can also create mountains.

2 Read the following paragraph from the section "Evaporation."

Evaporation is driven by the sun. The sun warms up the water on the surface of the ocean. The tiny parts that make up water start moving around quickly and spread apart. The water turns into a gas.

Based on this sentence, which of the following statements is TRUE?

(A) Heat changes liquid water into a gas.

(B) The sun creates clouds out of water.

(C) Evaporation happens when water cools.

(D) When tiny parts of water warm up, they get closer together.

3 HOW does water vapor become a cloud?

(A) It evaporates and becomes solid.

(B) It heats up and turns into a gas.

(C) It falls after condensation happens.

(D) It cools down and turns into liquid.

4 Complete the sentence.

Because of glacial retreat, ____

(A) there are more valleys being carved.

(B) the stages of the water cycle are changing.

(C) there is less freshwater on Earth than there used to be.

(D) glaciers are moving and making giant lakes.

This article is available at 5 reading levels at https://newsela.com.