Ocean Presentation

Water Cycle

"We forget that the water cycle and the life cycle are one "Jacques Cousteau.

Objectives

• Describe how water moves through the Earth's water cycle, including the processes of evaporation, condensation, and precipitation.

• Recognize the importance of clean water for life on Earth.

let's learn about water

Water (H2O) is an unique substance because it exists naturally in all three states of matter - solid, liquid and gas. Water is much more than a natural resource; it is a vital element that sustains life on our planet and plays a fundamental role in ecosystems, the economy and the quality of human life. Its conservation and responsible management are imperative to ensure a sustainable future for generations to come.

WHAT IS THE WATER CYCLE?

Water in the atmosphere is a gas. It forms clouds and falls to earth as a liquid or solid. This is called precipitation. Precipitation can be rain, snow, or ice. Some of the precipitation soaks into the ground where it becomes groundwater. This process is called infiltration. Groundwater gets taken up by plants. Plants release water back into the atmosphere as a gas through transpiration. The rest of the precipitation goes into streams, lakes, and rivers as runoff. These streams lead to the largest body of water: the ocean. Water from streams, rivers, and the ocean returns to the atmosphere through evaporation to start the cycle over again.

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Evaporation The process where water at the surface turns into water vapors. The water absorbs heat from sunlight which allows water to change forms. Oceans, lakes and rivers are the main source of evaporation.

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CondensationAs water vaporizes into water vapor, it rises up in the atmosphere. Because of the low temperature at high altitudes, the water vapor changes into tiny particles of water droplets

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SublimationSublimation also contributes to water vapor in the air. Sublimation converts ice directly into water vapor, bypassing the liquid phase. This process only occurs when the temperature is very low or the pressure is extremely high. Sublimation can occur in the North and South pole from ice caps or ice sheets.

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Precipitation Precipitation occurs when the water vapor in the air (clouds) change temperatures again and transform back into liquid water. Precipitation can occur as rain, snow, sleet, or hail depending on changing temperatures and pressure

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TranspirationAs water is precipitated, some is absorbed by the soil. This water enters the process of transpiration. Transpiration is similar to evaporation. The roots of plants absorb water and push it toward leaves where it is used for photosynthesis. The extra water is moved out of leaves through tiny openings as water vapor and then enters the biosphere and exits the gaseous phase.

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Runoff The water that pours down from precipitation contributes to run off. Runoff is the process where water runs over the Earth. Water displaces topsoil and moves minerals along with the stream. The runoff combines with streams and other channels to enter lakes and oceans.

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InfiltrationSome of the water that precipitates does not runoff into the rivers and is absorbed by the plants or gets evaporated. It moves deep into the soil and this is called infiltration.

Why is the water cycle important?

The water cycle ensures availability of water for all living organisms and regulates the weather patterns on the planet If water did not recycle itself naturally, we would run out! And clean water is essential to our lives!

Vocabulary

condense change from water vapor (gas) into liquid water (water vapor condenses when it is cooled) condensation the process by which water vapor changes into liquid water soaks streams evaporate to change from liquid water into a gas (water evaporates when heat is added) evaporation the process by which liquid water changes into water vapor precipitation: rain, snow, sleet, or hail water cycle the movement of water from Earth’s land, through rivers, toward the ocean, to the air, and back to the land

Topsoil Biosphere Gaseous phase