The water cycle

Lesson: The Importance of the Water Cycle

One important substance that is recycled in nature is water. Water on earth is continuously moving from land to the sky and back again. This process is known as water cycle.

Although there is a continuous cycle of water, you might also wonder if there will come a time when we run out of water. Do you know that about 97% of the water on earth is in the seas or oceans? Thus, only 3% of this water is fresh or potable. It contains very little or no salt. The majority of it is locked up in the ice and in the ground. Therefore, only about 1% of the water on earth is available for use. It is found in rivers, lakes, ponds, and in the atmosphere in the form of water vapor.

Firstly, water from the rivers, seas, and ponds evaporates into water vapor. Warm air carries the water vapor upward. As the water vapor rises, it cools and condenses into tiny water droplets. The tiny water droplets combine to form clouds. The clouds get heavy when a lot of water condenses. When that happens, the water droplets fall back to the earth as rain. Finally, the rain flows back to the rivers, ponds, and seas. The whole cycle repeat itself.

The water cycle, also known as the hydrologic cycle, is the continuous movement of water between Earth’s water supply and the air. It is always changing and in motion. As water goes through its cycle, it can be seen in three forms, namely: solid (ice), liquid (water), and gas (water vapor). How do these changes happen?​

If heat is added to ice, it melts. If heat is added to water, it evaporates. Evaporation is a process of changing liquid to gas, which is called water vapor.

If heat is taken away from water vapor, it undergoes another process which is called condensation. It is a process when gas (water vapor) turns into liquid form in the clouds.

When water droplets become big and heavy in the clouds, they start to drop on the earth’s surface as precipitation. They may be in solid (snowflakes) or liquid (raindrops) form.

IMPORTANCE OF WATER CYCLE

The processes of evaporation, condensation, and precipitation go on and on, completing the cycle. The water cycle is an important process that recycles water and nutrients. It also helps purify the water. During its evaporation process, the purification of water happens and becomes sterilized when exposed to the ultraviolet rays of the sun.

The water cycle is important not only for the survival of life on Earth, but to the climate too. For example, when water evaporates, it absorbs energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment.

IMPORTANCE OF WATER CYCLE

The processes of evaporation, condensation, and precipitation go on and on, completing the cycle. The water cycle is an important process that recycles water and nutrients. It also helps purify the water. During its evaporation process, the purification of water happens and becomes sterilized when exposed to the ultraviolet rays of the sun.

The water cycle is important not only for the survival of life on Earth, but to the climate too. For example, when water evaporates, it absorbs energy from its surroundings and cools the environment. When it condenses, it releases energy and warms the environment.

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https://www.youtube.com/watch?v=ncORPosDrjI

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1. What do you think is the illustration about?

2. What are the different forms of water in our environment?

3. Do you think each form of water is important? Why do you think so?

LET'S CHECK YOUR UNDERSTANDING!

Multiple Choice

Your mother washed clothes early this morning. She hanged the wet clothes in the clothesline under the sun. What happened with the wet clothes at the end of the day?

• The wet clothes became dry

• The wet clothes shrink.

• The wet clothes became bigger.

• The clothes will still be wet.

Multiple Choice

Mark Gabrielle notices a puddle of water on his way home from school. The next day the puddle is gone. What most likely happened to the puddle of water?

• evaporated

• melted

• condensed

• precipitated

Multiple Choice

When it is raining, the water that is falling down is in what stage of water cycle?

• runoff

• precipitation

• evaporation

• condensation

Multiple Choice

An ice cube placed outside in sunlight melts quickly. Which best explains the event?

• The ice cube is solid.

• The sun is far away.

• The sun makes heat.

• The ice cube looks clear.

Multiple Choice

What do you think will happen if oceans evaporate, but no rain falls?

• The clouds could not be formed.

• The bodies of water will dry up.

• The surroundings will be cold.

• The bodies of water will be clear and clean