OUR CHANGING EARTH

                                                    OUR CHANGING EARTH

Q. What are the endogenic forces and exogenic forces of earth movements?

Ans: Endogenic forces are -

1) Earthquake

2) Volcano

3) Tectonic Movements etc.

Exogenic forces are - 

1) Water

2) Waves

3) Ice

4) Wind etc.

Q. What do you mean by Endogenic forces?

Ans: The term endogenic means internal processes and phenomena that occur beneath the surface of the Earth or any other celestial body. Earthquake, volcano are some examples of endogenic forces.

Q. What do you understand by tectonic activity?

Ans: Earth's crust is fractured into 20 lithospheric plates of different sizes. They are generally considered to be about 100 km thick. They keep shifting and sliding at a very slow speed of a few millimetres in a year in different directions.The movement of these plates is commonly known as tectonic activity.

Q. What are the types of tectonic plate movements?

Ans: 1) Transform Boundaries: Sideways movement of two plates alongside each other is known as transform boundaries.

2) Divergent Boundaries: When two plates drift apart, they may cause valleys.

3) Convergent Boundaries: When two plates come together one of them slides over the other. This is called converging boundaries.

Q.What is an earthquake? 

Ans: An earthquake is a sudden tremour or movement of thr Earth's crust. It originates naturally at or below the surface.

Q. What are the causes of an earthquake?

Ans: Generally, Earthquake occur due to following two reasons:

a) They can occur due to exploisive volcanic eruptions.

b) They can be triggered by tectonic activity associated with plate margins and faults.

Q. What is hypocentre?

Ans: The point of origin of the earthquake is called the focus or hypocentre.

Q. Wht is epicentre?

Ans: The above point of the hypocentre or focus is called the epicentre.

Q. How do we measure the strength and magnitude of an earthquake?

Ans: On Richter scale.

Q.Who created the Richter Scale?

Ans: Charles Francis Richter.

Q. What is Volcano?

Ans: A Volcano is an opening ,or rupture, on the Earth's surface or crust, which allows hot, molten rock, ash and gases to escape from below the surface. The word volcano is derived from Italian volcano, after Vulcan, the Roman god of fire.

Q. Named two active volcanos.

Ans: 1) Mt. Vesuvias near Naples in Italy

2) Mt. Etna on the island of Sicily.

Q. What is exogenic or exogenous forces?

Ans: Exogenic refers to external processes and phenomena that occur on or above the Earth's surface. Weathering, Erosion ,sedimentation etc. are exogenic processes.

1) Weathering: It is the breaking down of rocks into small pieces by various effects of nature like wind, water, temperature variations ,etc.

2 Erosion: It is the removal of solids ( sediment, soil, rock, and other particles) in the natural environment. It usually occurs due to transport by wind, water, or ice.

3) Sedimentation: It is the collection and deposition of eroded and naturally transported material.

Q.What is waterfall?

Ans: A waterfall is a place where flowing water rapidly drops from an elevation as it flows over a steep region or a cliff.

Q. Name the tallest waterfall in the world.

Ans: Angel waterfall, located in Venezuela.

Q. Name the largest waterfall in the world.

Ans: Victoria waterfall.

Q. What are the features form by a river?

Ans: 1) Meanders: A meander in general is a bend in the course of the river.A large bend or loop in the course of a flowing river is known as a meander.

2) Ox- bow lake: It is a shallow U- shaped or C- shaped body of water formed when a wide meander from the main stream of a river is cut off to create a lake.

3) Floodplain: It is flat or nearly flat land adjacent to a stream or river that experiences occasional or periodic flooding.

4) Levees: it is a natural and artificial slope , wall to regulate water levels.

5) Delta: It is a landform that is created at the mouth of a river where that river flows into an  ocean , sea ,estuary, lake,etc.

Q. Write about the landforms created sea waves.

 Ans: 

1)Sea caves: It is a type of cave formed by the wave action of the sea. The primary process involved is erosion in the rocky faces on the seashore.

2) Sea arches: It is a natural arch or bridge made of stone that has been created through the process of land, wind and water erosion.

3) Sea cliff: The sea water coast rising almost vertically above the sea water is called a sea cliff.

4) Sea beaches: The span of the seashore which is flat and the waves leave behind sediments at these places in the form of fine sand are called beaches.

 Q. What is Glacier?

Ans: A Glacier is a large mass of ice like a frozen river moving slowly over some land surface or down a valley.