Geography Class 7: Water

Water Cycle: 

The interaction by which water persistently changes its structure and courses between seas, atmosphere, and land is known as the water cycle. 

Distribution of Water

Total Volume of Water on Earth – 1.386 Billion Km

Salt Water – 97.5%

Fresh Water – 2.50 (0.3% in liquid form)

Volume of Water in Oceans – 1,338,000,000 Km

Volume of Water in ICE and Snow -24,364,000 Km

Ground Water Volume – 23,400,000 km

Volume of Water in Lakes – 176,400 km

Volume of Water in the Atmosphere – 12,900 km

Volume of Water in Swamps – 11,470 km

Volume of Water in Rivers – 2,120 km

Volume of Water in Biological Water – 1,120 km

Circulation of water bodies: 

Sea Circulation: 

Seawater continues to move persistently and is rarely still. The developments that happen in seas can be extensively classified as waves, tides, and flows. 

Waves: 

When the water on the outer layer of the sea rises and falls, they are called waves. A quake, a volcanic ejection, or submerged avalanches can move a lot of seawater. Subsequently, a gigantic tsunami, considered torrent that might be as high as 15 m, seems to be shaped. The most significant wave at any point estimated was 150 m high. For instance, a torrent of 2004 caused boundless harm in the seaside spaces of India. The Indira Point in the Andaman and Nicobar Islands got lowered after the torrent. 

Tides: 

The musical ascent and fall of seawater twice in a day is known as a tide. It is an elevated tide when water covers a large part of the shore by ascending to its most significant level. It is low tide when water tumbles to its most minor level and retreats from the shore. The solid gravitational force applied by the Sun and the Moon on the Earth’s surface causes the tides.

During the full moon and new moon days, the Sun, the Moon, and the Earth are in a straight line, and the tides are most elevated. These tides are called Spring tides. 

When the Moon is in its first and last quarter, the seawater gets attracted slantingly to inverse headings by the gravitational draw of the Sun and Moon, bringing about low tides. These tides are called Neap tides. 

Advantages of High tides:

The elevated tides help in route by raising the water level near the shores, which helps the boats to show up at the harbour without any problem.

They additionally help in fishing as a lot more fish come nearer to the shore during the soaring tide.

The ascent and fall of water which happens due to tides are being utilised to produce power in certain spots. 

Sea flows: 

Sea ebbs and flows are surges of water streaming continually on the sea surface in unequivocal ways. They might be warm or cold.

The warm sea flows begin close to the Equator and move towards the Poles. The chilly flow takes water from the polar region to the tropical region. 

The sea ebb and flow impacts the temperature states of the sea space. The regions where the warm and cold flows meet give the best fishing grounds on the planet. Oceans around Japan and the eastern shore of North America are such models. The regions where a warm and cold current meets likewise experience hazy climates, making it hard for the route. 

Ocean Currents:

Owing to gravity, the movement of wind and the density of water, there is a directional movement in seawater, which is predictable in nature. This movement of seawater is known as Ocean Current. When movement of water is vertical, the same is referred to as upwellings or downwellings. 

Ocean circulations:

Large scale movement of seawater is not known as Ocean Circulation.

Types of Ocean Circulations:

Wind driven or surface circulations: 

The warm upper waters from the tropics are carried poleward by surface circulation. Heat is dispersed as it travels from the oceans to the atmosphere.

Thermohaline circulation or Deep Circulations

Water’s Sinking and Cooling in the Polar regions is the reason for Deep Circulations.

Conclusion

Our Earth is a water body and contains 70% of water. This water continuously goes through the cyclic process known as water cycle. It is continuous movement of water from the surface to the atmosphere and back, in this process water  constantly changes its form from liquid to gas then gas to solid and again from solid to liquid. This cycle is essential for maintaining the water flow in rivers and sea. In oceans, water persistently moves  from one area to another with the agents like waves, tides, sea flows.  This moment is necessary for maintaining sea life. It is our duty to not interrupt with the water cycle, so that life on earth will continue to sustain.