WATER

 Water Cycle

 The water cycle is a natural process that continuously happens on earth. The water cycle maintains the amount of water on the earth. The process by which water continually changes its form and circulates between oceans, the atmosphere, and land is known as the water cycle.It can be divided into four phases:

Evaporation - It is a process when the water from the earth’s surface gets converted into water vapour due to the heat of the sun. The water vapour then gets into the air.

Condensation - The water vapour rises up in the atmosphere and get accumulated above, condenses and form water droplets. These droplets collect together and form clouds.

Precipitation - When the volume of droplets increases in the atmosphere, it falls on the earth as rainfall also called as Precipitation. Sometimes it also occurs as snowfall in some areas.

Collection of Water - As the water falls back on the earth, it travels along the surface and gets accumulated at different places like lakes, rivers, sea, oceans and under the ground. That's how the amount of water is regulated on the earth.

A terrarium is a small enclosed environment for plants, typically made of glass or plastic.

Distribution of Water Bodies Three-fourths of the earth’s surface is covered by water.

Inland Sea

• An inland sea is a very large body of water that is almost surrounded by land.

• It does not open fully into the ocean but may have a small connection.

• Example: Caspian Sea (world’s largest inland sea), Dead Sea.

Largest Inland Sea: Caspian Sea

We float in the Dead Sea because its water is much denser than normal water.

• The Dead Sea has a very high amount of salt dissolved in it.

• This makes the water heavier and denser than ordinary sea water.

• Our body is less dense than salty Dead Sea water, so instead of sinking, we float naturally.

Ocean Circulation

The circulation or the movement of the water in the ocean in various ways is termed an ocean circulation.

The water of the oceans is not calm like that of ponds or lakes or other such water bodies. It is always in a state of movement.

Waves

When the water on the surface of the ocean rises and falls alternately, they are called waves.

During a storm, the winds blowing at very high-speed form huge waves. These may cause tremendous destruction. 

They are mainly caused by winds blowing across the water, transferring its energy and causing the water to move in a circular motion.

A great quantity of ocean water can be shifted because of an earthquake, a volcanic eruption, or underwater landslides. As a result, huge tidal wave is formed such as Tsunamis.

2004 Tsunami Attack – Reason & How It Happened

On 26 December 2004, a huge undersea earthquake occurred near Sumatra, Indonesia. The earthquake was caused when one big tectonic plate(Indian Plate) suddenly slid under another plate (Burma Plate). This sudden movement pushed up a massive amount of seawater. The displaced water created giant waves (tsunami) that spread quickly across the Indian Ocean. These waves struck coasts of many countries (India, Sri Lanka, Thailand, etc.), causing great destruction and loss of life.

https://www.youtube.com/watch?v=Wx9vPv-T51I

Tides

The rhythmic rise and fall of ocean water twice a day is called a tide.

https://www.youtube.com/watch?v=M3hAhNsyf7k

Types of Tides:

• High Tide: When the sea level rises and water comes towards the shore.

• Low Tide: When the sea level falls and water goes back from the shore.

The strong gravitational pull exerted by the sun and the moon on the earth's surface causes the tides. The tides are at their highest point at the time of the full moon and new moon days.

On full moon and new moon days, the Sun, Moon, and Earth are in a straight line, leading to spring tides (highest tides).

During the first and last quarter of the moon, the Sun and Moon pull water in different directions, causing weaker tides, called neap tides.

Importance of Tides: Help ships to enter and leave ports. Used for producing electricity (Tidal Energy).

Ocean currents

Ocean Currents

• Ocean currents are continuous streams of water flowing on the ocean surface in fixed directions. They can be warm or cold.

Warm Currents

• Originate near the equator and move towards the poles.

• Raise the temperature of nearby land areas.

• Example: Gulf Stream, Kuroshio Current (From Philippines/Japan toward North Pacific)

  
  

  
  

Cold Currents

• Originate from polar regions and flow towards the tropics.

• Lower the temperature of nearby coastal regions.

• Meeting points of warm and cold currents create the world’s best fishing grounds.

• Example: Labrador Current, California Current,  Humboldt (Peru Current) Current

Importance of Ocean Currents

1. Affect the climate of coastal regions.

2. Influence navigation and trade routes.

3. Provide rich fishing grounds.

4. Help in the distribution of marine life and nutrients.

5. Affect rainfall and weather patterns.

1. Answer the following questions.

(i) What is precipitation?
Precipitation is the process in which water falls from clouds to the Earth in the form of rain, snow, sleet, or hail.

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(ii) What is the water cycle?
The water cycle is the continuous movement of water between the oceans, land, and atmosphere through evaporation, condensation, and precipitation.

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(iii) What are the factors affecting the height of the waves?
The height of the waves depends on:

• The speed of the wind

• Earthquakes, volcanic eruptions, or underwater landslides

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(iv) Which factors affect the movement of ocean water?
The movement of ocean water is affected by:

• Temperature

• Gravitational pull of the sun and the moon

• Winds

• Warm and cold currents

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(v) What are tides and how are they caused?
Tides are the rise and fall of ocean water that happen twice every day.
They are caused by the gravitational pull of the moon and the sun on the Earth.

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(vi) What are ocean currents?
Ocean currents are streams of water that flow constantly on the ocean surface in a fixed direction.
They may be warm or cold.