Water A Precious Resource - Class 7 Geography - Extra Questions

Very short answer type question.
What happens during low tide?

During low tide water falls to its lowest level and recedes from the shore.
Tides are caused by the gravity of both the moon and the sun “pulling” at the water in the sea. Because the Earth is constantly turning, the “pull” of gravity affects different places as each day goes on - so when the tide is “out” in your area, it is “in” somewhere else. But the water level at high tide changes too!


Very short answer type question.
What happened to the Indira point during the tsunami of 2004?

It got submerged.
The Indira Point lighthouse was commissioned into service on 30 April 1972. Located 500 kilometres north of the epicenter of the 2004 Indian Ocean earthquake, the southernmost tip subsided 4.25 metres after the earthquake, and many of the inhabitants went missing in the tsunami that followed


What are tides and how are they caused?

Tides are the rhythmic rise and fall of ocean water that occur twice in a day. The strong gravitational pull exerted by the sun and the moon on the earth's surface causes the tides. 


Very Short Answer Type Questions:
What makes the water of lakes and rivers unsuitable for human use?

Discharge of waste material into lakes and rivers makes the water unsuitable for human use.


Give reasons.
Ocean water is salty.

The water of the oceans is salty as it contains large amount of dissolved salts. 


Fill in the blanks with appropriate words to complete each sentence:
The hydrosphere comprises water in the form of ______, water and ______.

The hydrosphere comprises water in the form of Ice, water and Water vapour.


What are oceans currents?

Ocean currents are streams of water flowing constantly on the surface in definite directions.


What are the factors affecting the height of the waves?

Winds, earthquakes, volcanic eruption or under water landslides are the factors affecting the height of the waves. The stronger the wind blows, the bigger the wave becomes.


What is a water cycle?

The water cycle is the process by which water continually changes its form and circulates between oceans, atmosphere and land.


Which factors effects the movement of ocean water?

Temperature, winds, gravitational pull of the sun, the earth and the moon, warm and cold currents are the factors that effects the movement of ocean water.


Long answer type question.
Give an account of ocean currents.

Ocean currents are streams of water flowing constantly on the ocean surface in definite directions. The ocean currents may be warm or cold. The warm ocean currents originate near the equator and move towards the poles. The cold current carry water from polar or higher latitudes to tropical or lower latitudes. For example the Labrador Ocean current is a cold current while the Gulf Stream is a warm current. The ocean current influence the temperature conditions of the area. Warm currents bring about warm temperatures over land surface. The areas where the warm current and cold currents meet provide the best fishing grounds of the world. For example seas around Japan and the eastern coast of North America. The areas where a warm and cold current meet also experience foggy weather and therefore navigation becomes difficult.


Long answer type question.
How do we classify ocean movements? Explain.

Ocean movements can be classified into waves, tides, and currents.
$$\bullet$$ When the water on the surface of the ocean rises and falls alternately, they are called waves. Waves are formed when winds scrape across the ocean surface. The stronger the wind blows, the bigger the wave becomes.
$$\bullet$$ The rhythmic rise and fall of ocean water twice in a day is known as a tide. Tides may be high or low. It is high tide when water covers much of the shore by rising to its highest level. It is low tide when waterfalls to its lowest level and recedes from the shore. Tides are caused due to the strong gravitational pull exerted by the sun and moon on the earth's surface. High tides help in navigation and fishing. The rise fall of water due to tides is being used to generate electricity in some places.
$$\bullet$$ Ocean currents are streams of water flowing constantly on the ocean surface in definite directions. The areas where the warm and cold currents meet provide the best fishing ground of the world. For example, seas around Japan and the Eastern Coast of North America.


Very short answer type question.
What happens during high tide?

During high tide waves rise high and water covers much of the shore.
The tidal force causes Earth—and its water—to bulge out on the side closest to the moon and the side farthest from the moon. These bulges of water are high tides. As the Earth rotates, your region of Earth passes through both of these bulges each day. When you're in one of the bulges, you experience a high tide.


Give reasons.
The quality of water is deteriorating.

Water is being used injudiciously. Whatever potable water is available, its quality is not good. It is because industrial effluents and untreated water of industries get mixed into streams and rivers. Sewerage water is also gets mixed into these water bodies. As a result, the quality of water is deteriorating day by day. 


Short answer type question.
How are high tides important?

High tides are important for various reasons:
-They help in navigation 
-They raise the water level close to the shore. This helps the ships to arrive at the harbor more easily.
-The high tides also help in fishing. Much more fish come closer to the shore during the high tides. This enables the fisherman to get a plentiful catch.
-The rise and fall of water due to tides is being used to generate electricity in some places.


Short answer type questions.
How are spring and neap tides formed.

During the full moon and new moon days, the sun, the moon, and the earth are in the same line and the tides are highest. These tides are called spring tides. But when the moon is in its first and last quarter, the ocean waters get drawn in diagonally opposite directions by the gravitational pull of sun and earth resulting in low tides. These tides are called neap tides. 


 What are the different stages of water cycle?

The stages involved in a complete water cycle are: 
Stage I: Evaporation - The heat of the sun falls on the water bodies like oceans, seas, lakes, rivers etc. The water slowly evaporates as vapours into the air.
Stage II: Condensation - As the vapours rise high, the cooler temperatures make them cool down and turn back into liquid. This is called condensation. Wind moves the liquid around, leading to the formation of clouds.
Stage III: Precipitation - Wind movements cause the clouds particles to collide. They become rain bearing clouds and fall back onto the earths surface by the process known as precipitation.
Stage IV: Runoff and Infiltration - The water either runs off into oceans, rivers and ground surface or is absorbed into the soil (infiltration).


Class 7 Geography Extra Questions