Academic Reading: 1

The Water Cycle

Water is always moving. It moves from the ocean to the sky, from the sky to the ground, and from the ground back to the ocean. This journey is called the water cycle. The water cycle has no beginning and no end. It repeats again and again, and it has been happening for millions of years.

The water cycle has several important steps. The first step is called evaporation. When the sun heats water in oceans, lakes, and rivers, some of the water turns into a gas called water vapor. This gas rises into the air. The sun is the main source of energy for this step, because heat is needed to change liquid water into vapor.

The second step is called condensation. As water vapor rises higher into the sky, the air becomes colder. Cold air cannot hold as much water vapor as warm air. So the vapor changes back into tiny drops of liquid water. These tiny drops join together and form clouds. Without condensation, clouds could not form at all.

The third step is called precipitation. When the drops of water in a cloud become too heavy, they fall back to the ground. This can happen as rain, snow, or hail, depending on the temperature outside. Precipitation is the main way that water returns from the sky to the land and the ocean.

The final step is called collection. Water that falls as precipitation collects in oceans, lakes, rivers, and under the ground. Some of this water is used by plants and animals. Some of it evaporates again, and the whole cycle starts over. Scientists study the water cycle carefully because it affects the weather, farming, and the amount of fresh water that is available for people to drink. Without this constant cycle, many parts of the world would not have enough fresh water to support life at all. Understanding each step of the cycle also helps people see why water is often described as a renewable resource, one that never truly disappears, even though it must still be used wisely and kept clean for everyone to share.