assignment on our changing earth

Arinjay Academy » Geography » NCERT Solutions for Class 7 Geography Chapter 3 – Our Changing Earth

NCERT Solutions for Class 7 Geography Chapter 3 – Our Changing Earth

1. Answer the following questions.

(i) Why do the plates move?

Answer – Plates on the surface of the earth move because of the intense heat produced by the Earth’s core. This heat causes convection cells in the mantle which in turn heats up the SIAL and SIMA layers. To distribute the heat and pressure evenly the plates on the surface move in a convergent and divergent manner.

(ii) What are exogenic and endogenic forces?

Answer – Exogenetic forces are those which occur on the surface of the earth and can be easily noticed, for example, Weathering, mass wasting, erosion and deposition.

Endogenetic forces on the other hand, are those which occur within the earth’s surface and lead to a change in the structures of the earth either horizontally or vertically, examples: folding and faulting, earthquakes and volcanism,

(iii) What is erosion?

Answer – Erosion is the gradual wearing away of rocks from the surface from one area and being transported to another area. The main agents of erosion are, rivers, winds, glaciers and tides. Valleys, mushroom rocks, Cliffs are examples of erosional landscapes.

(iv) How are flood plains formed?

Answer – Flood plains are formed when the river due to excessive water either from the rain or any other physical barrier in its path spills along its bank. The sediments carried by the river which is mostly alluvium, gets deposited on either sides of the bank and gradually form raised platforms beside the river. These are known as flood plains.

(v) What are sand dunes?

Answer – Sand dunes are heaps of sand found either in the desert or near the beaches which are formed due to the transportation and depositional action of the winds. The sand dunes usually are pyramidal in shape and can extend over hundreds of kilometres.

(vi) How are beaches formed?

Answer – Beaches are formed by the depositional action of waves and tides. They deposit sand, pebble and gravel along the shoreline which slowly dets layered and forms into beaches.

(vii) What are ox bow lakes?

Answer – When the river reaches its matured stage, it begins to meander extensively along its path. If the meandering is so much that, the river is unable to continue flowing on that channel, it shifts to a straighter path, thus leaving the meandered channel. These meandered channels do not receive water from the river any more and are separated from the main channel. These are then called ox bow lakes.

Tick the correct answer.

(i) Which is not an erosional feature of sea waves? (a) Cliff (b) Beach (c) Sea cave

Answer: (b) Beach

(ii) The depositional feature of a glacier is: (a) Flood plain (b) Beach (c) Moraine

Answer: (c) Moraine

(iii) Which is caused by the sudden movements of the earth? (a) Volcano (b) Folding (c) Flood plain

Answer: (a) Volcano

(iv) Mushroom rocks are found in: (a) Deserts (b) River valleys (c) Glaciers

Answer: (a) Deserts

(v) Ox bow lakes are found in: (a) Glaciers (b) River valleys (c) Deserts

Answer: (b) River valleys

3. Match the following.

4. Give reasons.

(i) Some rocks have a shape of a mushroom: Mushroom rocks are found in the deserts and form when the wind velocity is higher in the lower surface of the rock eroding the rock from all around and forming a pillar like structure. While the upper part of the rock remains less altered. The velocity of winds are higher near the surface of the deserts.

 (ii) Flood plains are very fertile. This is because, the rivers deposit new alluvium each year when they overflow its banks and submerge the flood plains with new sediments and minerals brought down from the mountains.

(iii) Sea caves are turned into stacks. Due to continuous erosion by the waves and wind action, the sea caves are slowly eroded into single standing pillars known as stacks that are found in the rocky beach landscapes.

(iv) Buildings collapse due to earthquakes. Earthquakes are sudden movements which occur within the earth and has tremendous effects on the surface. The high frequency vibrations which are released from the focus of the earth quakes lead to a disbalance in the structures over the surface and thus buildings or any other structures collapse.

NCERT Solutions for Geography (Social Science)

• Chapter 1 – Environment
• Chapter 2 – Inside Our Earth
• Chapter 3 – Our Changing Earth
• Chapter 4 – Air
• Chapter 5 – Water
• Chapter 6 – Natural Vegetation and Wild Life
• Chapter 7 – Human Environment: Settlement Transport and Communication
• Chapter 8 – Human Environment Interactions
• Chapter 9 – Life in the Deserts

NCERT Solutions for Class 7

Cbse notes for class 7, worksheets for class 7, leave a comment cancel reply.

Class 7 Geography Chapter 3 Our Changing Earth Extra Questions and Answers

Class 7 Geography Chapter 3 Our Changing Earth extra questions and answers available here in PDF format. Solving class 7 extra questions help students to revise the Chapter most competently. We prepared these questions as per the latest NCERT book and CBSE syllabus. Practicing these extra questions before the exam will ensure excellent marks in the exam.

Our Changing Earth Class 7 Geography Extra Questions and Answers

Very short extra questions and answers.

1. What are the major agents of erosion?

Answer:  Water, wind and ice are the major agents of erosion.

2. Define loess?

Answer: When sand is deposited in large areas, it is called loess.

3. What is vent?

Answer:  The narrow opening of a volcano is called vent.

4. What is a seismograph?

Answer:  An earthquake is measured with a machine called a seismograph.

5. What is the name of the scale used to measure earthquakes?

Answer:  The magnitude of the earthquake is measured on the Richter scale.

6. Write some examples of coastal landforms?

Answer:  Examples of coastal landforms are sea caves, sea arches, stacks and sea cliff.

7. Write names of a few rivers of the world that form a delta.

Answer:  Ganga-brahmaputra, Zaire, Murray-Darling, Amazon, Nile, Murray-Darling

8. What are distributaries?

Answer: The river begins to break up into a number of streams called distributaries.

9. Why do the plates move?

Answer: Plates move because of the movement of the molten magma inside the earth.

10. How are beaches formed?

Answer: Beaches are formed when the sea waves deposit sediments along the shores.

11. What is erosion?

Answer: Erosion is the wearing away of the landscape by different agents like water, wind and ice.

12. What are meanders?

Answer: As the river enters the plain it twists and turns forming large bends known as meanders.

13. What are Lithospheric plates?

Answer:  The lithosphere is broken into a number of plates known as the Lithospheric plates.

14. How much do lithospheric plates move in a year?

Answer: Lithospheric plates move around very slowly – just a few millimetres each year.

15. What is a volcano?

Answer:  A volcano is a vent (opening) in the earth’s crust through which molten material erupts suddenly.

Short Extra Questions and Answers

1. What are the two processes which wear away the landscape?

Answer:  The landscape is being continuously worn away by two processes – weathering and erosion.

2. How do glacial moraines form?

Answer: The material carried by the glacier such as rocks big and small, sand and silt gets deposited. These deposits form glacial moraines.

3. What are the processes that create different landforms on the surface of the earth?

Answer:  The process of erosion and deposition create different landforms on the surface of the earth.

4. Define the term focus and epicenter.

Answer: The place in the crust where the movement starts is called the focus. The place on the surface above the focus is called the epicentre.

5. Why are the flood plains very fertile?

Answer:  The flood plains are very fertile because these plains are formed by the fine soil and sediments brought by the flood water.

6. What is a delta?

Answer:  A delta is a feature formed when rivers drop off sediments in low-lying areas, usually as they enter the ocean, sea or an estuary. It is sometimes shaped like a triangle.

7. How does waterfall form?

Answer: The running water in the river erodes the landscape. When the river tumbles at steep angle over very hard rocks or down a steep valley side it forms a waterfall.

8. What are some other methods used to predict an earthquake?

Answer:  Some common earthquake prediction methods adopted locally by people include studying animal behaviour; fish in the ponds get agitated, snakes come to the surface.

9. What are earthquakes?

Answer: When the Lithospheric plates move, the surface of the earth vibrates. The vibrations can travel all-round the earth. These vibrations are called earthquakes.

10. What are sand dunes?

Answer:  When the wind blows, it lifts and transports sand from one place to another. When it stops blowing the sand falls and gets deposited in low hill – like structures. These are called sand dunes.

11. What are the three types of earthquake waves?

Answer:  There are three types of earthquake waves:

• P waves or longitudinal waves
• S waves or transverse waves
• L waves or surface waves

Long Extra Questions and Answers

1. Name some waterfalls.

Answer:  The highest waterfall is Angel Falls of Venezuela in South America. The other waterfalls are Niagara Falls located on the border between Canada and USA in North America and Victoria Falls on the borders of Zambia and Zimbabwe in Africa.

2. What are exogenic and endogenic forces?

Answer:  Exogenic forces – The forces that work on the surface of the earth are called as Exogenic forces.

Endogenic forces – The forces which act in the interior of the earth are called as Endogenic forces.

3. How are flood plains formed?

Answer: At times the river overflows its banks. This leads to the flooding of the neighbouring areas. As it floods, it deposits layers of fine soil and other material called sediments along its banks. This leads to the formation of a flat fertile flood plain.

4. What are ox bow lakes?

Answer:  Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer. In due course of time the meander loop cuts off from the river and forms a cut-off lake, also called an ox-bow lake.

5. Why some rocks have a shape of a mushroom?

Answer: Winds erode the lower section of the rock more than the upper part. Therefore, such rocks have narrower base and wider top which resembles a mushroom. These rocks in the shape of a mushroom, commonly called mushroom rocks.

6. How earthquakes are measured?

Answer:  An earthquake is measured with a machine called a seismograph. The magnitude of the earthquake is measured on the Richter scale. An earthquake of 2.0 or less can be felt only a little. An earthquake over 5.0 can cause damage from things falling. A 6.0 or higher magnitude is considered very strong and 7.0 is classified as a major earthquake.

7. How a delta is formed?

Answer:  As the river approaches the sea, the speed of the flowing water decreases and the river begins to break up into a number of streams called distributaries. The river becomes so slow that it begins to deposit its load. Each distributary forms its own mouth. The collection of sediments from all the mouths forms a delta.

8. Sea caves are turned into stacks. Give reason.

Answer:  Sea waves continuously strike at the rocks. Cracks develop. Over time they become larger and wider. Thus, hollow like caves are formed on the rocks. They are called sea caves. As these cavities become bigger and bigger only the roof of the caves remain, thus forming sea arches. Further, erosion breaks the roof and only walls are left. These walls like features are called stacks.

9. Explain the work of ice.

Answer:  Glaciers are “rivers” of ice which too erode the landscape by bulldozing soil and stones to expose the solid rock below. Glaciers carve out deep hollows. As the ice melts they get filled up with water and become beautiful lakes in the mountains. The material carried by the glacier such as rocks big and small, sand and silt gets deposited. These deposits form glacial moraines.

10. Why do buildings collapse due to earthquakes?

Answer:  Buildings collapse due to earthquakes because

• Earthquakes move the ground side to side and up and down—simultaneously. The force behind this movement is powerful enough to turn soft soil instantly into quicksand, eliminating its ability to bear weight.
• Most of the buildings are not safe enough to resist the vibrations of the earthquakes due to shallow foundation and lack of adequate steel in the interior design.

11. Write a short note on earthquake preparedness.

Answer:  Although earthquakes cannot be predicted, the impact can certainly be minimised if we keep the following points in mind.

Safe Spot – Take shelter during an earthquake under a kitchen counter, table or desk, against an inside corner or wall.

Stay Away from – Fire places, areas around chimneys, windows that shatter including mirrors and picture frames.

Be Prepared – Spread awareness amongst our friends and family members and face any disaster confidently.

12. Write a short note on work of wind.

Answer:  (i) An active agent of erosion and deposition in the deserts is wind. In deserts we see rocks in the shape of a mushroom, commonly called mushroom rocks. Winds erode the lower section of the rock more than the upper part. Therefore, such rocks have narrower base and wider top.

(ii) When the wind blows, it lifts and transports sand from one place to another. When it stops blowing the sand falls and gets deposited in low hill – like structures. These are called sand dunes.

(iii) When the grains of sand are very fine and light, the wind can carry it over very long distances. When such sand is deposited in large areas, it is called loess. Large deposits of loess are found in China.

13. Give an account of the work of sea waves.

Answer:  (i) The erosion and deposition of the sea waves gives rise to coastal landforms. Sea waves continuously strike at the rocks. Cracks develop. Over time they become larger and wider. Thus, hollow like caves are formed on the rocks. They are called sea caves.

(ii) As these cavities become bigger and bigger only the roof of the caves remain, thus forming sea arches.

(iii) Further, erosion breaks the roof and only walls are left. These walls like features are called stacks.

(iv) The steep rocky coast rising almost vertically above sea water is called sea cliff.

(v) The sea waves deposit sediments along the shores forming beaches.

14. Explain the work of a river.

Answer:  (i) The running water in the river erodes the landscape. When the river tumbles at steep angle over very hard rocks or down a steep valley side it forms a waterfall.

(ii) As the river enters the plain it twists and turns forming large bends known as meanders.

(iii) Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer. In due course of time the meander loop cuts off from the river and forms a cut-off lake, also called an ox-bow lake.

(iv) At times the river overflows its banks. This leads to the flooding of the neighbouring areas. As it floods, it deposits layers of fine soil and other material called sediments along its banks. This leads to the formation of a flat fertile floodplain. The raised banks are called levees.

(v) As the river approaches the sea, the speed of the flowing water decreases and the river begins to break up into a number of streams called distributaries. The river becomes so slow that it begins to deposit its load. Each distributary forms its own mouth. The collection of sediments from all the mouths forms a delta.

NCERT Solutions for Class 6, 7, 8, 9, 10, 11 and 12

NCERT Solutions For Class 7 Geography Social Science Chapter 3 Our Changing Earth

October 2, 2019 by phani

Question  1. Answer the following questions briefly:

• Why do the plated move?
• What are exogenic and endogenic forces?
• What is erosion?
• How are flood plains formed?
• What are sand dunes?
• How are the beaches formed?
• What are the ox-bow lakes?
• Exogenic forces are those forces which act on the surface of the earth and cause changes on the surface of the earth. Examples: Weathering, gradation, erosion, deposition.
• Endogenic forces are those forces which originate in the interior of the earth and cause changes on the surface of the earth. Examples: Volcanoes and Earthquakes.
• Erosion Erosion is the wearing away of the landscape by different agents like running water, glacier, wind, ground water and sea waves.
• During rains rivers overflow their banks.
• This leads to the flooding of the nearby areas.
• After the flood has receded, a layer of fine material and other material is deposited over the plain in the form of sediments.
• This leads to the formation of the flood plain.
• Sand Dunes Sand dunes are heaps of sand deposited at a place by the wind’s action in the desert areas.
• Sea waves strike the coasts.
• They erode the coasts and carry the eroded material in the form of silt and other material.
• When they withdraw they deposit the silt and other material (sediments) along the shore, forming wide beaches.
• When the meander loop is cut-off from the main river, it forms a cut-off lake.
• Its shape is like an ox-bow.
• Hence, the cut-off lake is called ox-bow lake.

Question  4. Give reasons:

• Some rocks have the shape of a mushroom.
• Flood plains are very fertile.
• Sea caves are turned into stacks.
• Buddings collapse due to earthquakes.
• When’ rocks fall in the course of running dust-storms, the suspended particles of sand strike the lower portion of the rocks and erode them.
• The upper portions of the rocks remain unaffected/uneroded.
• In course of time the rocks take up the shape of a mushroom.
• They are made of the silt and other material brought by floods.
• Due to spread of the new silt, the flood plains are fertile areas.
• The sea waves strike the coasts and erode the soft rocks. Hard rocks remain uneroded. This action results in the formation of sea caves.
• In course of time the roofs of the caves also come down due to erosion and the arms/walls of the caves remain standing like pillars. • These pillars-like formations are termed as stacks.
• Most buildings are not built/made earthquake-proof.
• When the earthquakes strike, the buildings are not capable of resisting the vibrations of the earthquakes.
• They tear apart due to shallow foundation, sub-standard interior material, and lack of adequate steel.
• They collapse and fall down like a pack of papers/cards.

Question 6. For fun. Solve the crossword puzzle with the help of given clues. Across 2. Loop like the bend of a river. 4. Solid form of water. 7. Moving mass of ice. 9. Sudden descent of water in the bed of a river. 11. Natural cavity on weak rocks formed by action of waves.

1. Read the ‘Earthquake – A case study’ given in the form of headlines that appeared in the newspapers after the quake. Arrange the events in the right sequence of their happening. 2. Imagine if a quake suddenly shook in the middle of the school day, where do you go for safety? Answer.

• in the open
• under the gates
• would keep pillow or cushion on our heads.

INTEXT QUESTIONS WITH THEIR ANSWERS

Question 1. Find out the names of a few rivers of the world that form a delta? Answer. Name of some rivers (See the Map):

• Mississippi—Missouri.
• Parana—Paraguay.
• Tigris—Euphrates.
• Ganga—Brahmaputra.
• The Yangtze.

Very Short Answer Type Questions

Question  1.  What do you know about the lithospheric plates? Answer:  The earth’s crust consists of several large and some small, rigid, irregularly— shaped plates, Le., slabs which cany continents and the ocean floor.

Question  2. How do the lithospheric plates move? Answer:   They move around very slowly, just a few millimeters each year.

Question  3. What is a volcano? Answer:   A volcano is a vent or opening in the earth’s crust through which molten material erupts suddenly.

Question  4.  Define focus’ and ‘epicentre’. [Imp.] Answer:  The place in the crust where the movement starts is called the ‘focus’. The place on the surface above the focus is called the ‘epicentre’.

Question  5.  Name the three types of earthquake waves. Answer:

• P waves or longitudinal waves
• S waves or transverse waves
• L wave or surface waves.

Question  6.  What is a seismograph? [V. Imp.] Answer:   A seismograph is a machine which measures an earthquake.

Question  7.  Name the scale on which the magnitude of the earthquake is measured. Answer:  Richter scale.

Question  8. Which earthquake is classified as a major earthquake? Answer:  An earthquake of 7.0 magnitude is classified as a major earthquake.

Question  9. Where is Victoria Falls located? [Imp.] Answer:  Victoria Falls is located on the borders of Zambia and Zimbabwe in Africa.

Question  10. What is delta? Answer: The collection of sediments from all the mouths forms a delta. It is a triangular-shaped landmass.

Question  11. Name some coastal landforms. Answer:  Sea caves, sea arches, stacks, and sea cliffs.

Question  12. How are glacial moraines formed?                              [V. Imp.] Answer:   The material carried by the glacier such as rocks big and small, sand and silt gets deposited. These deposits form glacial moraines.

Question  13. Name the two processes which wear away the landscape. Answer:  Weathering and erosion.

Question  14. What does the process of erosion and deposition create? Answer:  The process of erosion and deposition create different landforms on the surface of the earth.

Question  15. Name a few rivers of the world that form a delta? Answer:  Nile, Zaire, Ganga-Brahmaputra, Hwangotto, Murray-Darling, Amazon, etc.

Short Answer Type Questions

Question  1. Mention the work of ice. Answer:  Glaciers are rivers of ice that erode the landscape by destroying soil and stones to expose the solid rock below. Glaciers carve out deep hollows. As the ice melts they get filled up with water and become beautiful lakes in the mountains. The material carried by the glacier such as rocks big and small, sand and silt gets deposited. These deposits form glacial moraines.

Question  2. What is an earthquake? What are some common earthquake prediction methods?[V. Imp.] Answer:  When the lithospheric plates move, the surface of the earth vibrates. The vibrations can travel all around the earth. These vibrations are called earthquakes. Some common earthquake prediction methods include studying animal behaviour, fish in the ponds get agitated, snakes come to the surface.

Question   3.  Give an account of earthquake preparedness.            [V. Imp.] Answer:   Earthquake is a natural calamity which we cannot stop. But we can minimise its impact if we are prepared before-hand. During an earthquake, we should shift to some safe spot. We should hide under a kitchen counter, table, or desk against an inside comer or wall. We should stay away from fireplaces, areas around chimneys, windows that shelter including mirrors and picture frames. Moreover, we should spread awareness amongst our friends and family members.

Long Answer Type Questions

Question  1.  Explain the work of a river.                [V. Imp.] Answer:  The running water in the river erodes the landscape. When the river tumbles at a steep angle over very hard rocks or down a deep valley side it forms a waterfall. While entering the plain the river twists and turns and forms large bends which are known as meanders. Due to continuous erosion and deposition along the sides of the meander, the ends of the meander loop come closer and closer.

In due course of time the meander loop cuts off from the river and forms a cut-off lake, which is also called an ox-bow lake. Sometimes, the river overflows its banks causing flood in the neighboring areas. As it floods, it deposits layers of fine soil and other material called sediments along its banks. As a result—a fertile floodplain is formed. The raised banks are called levees.

As the river approaches the sea, the speed of the flowing water decreases, and the river begins to break up into several streams known as distributaries. Then a time comes when the river becomes very slow and it begins to deposit its load. Each distributary forms its own mouth. The collection of sediments from all the mouths forms a delta, which is a triangular landmass.

Question  2. Give an account of the work of wind. [V. Imp.] Answer:  Wind is an active agent of erosion and deposition in the deserts. In deserts, we often notice rocks in the shape of a mushroom, known as mushroom rocks. Winds erode the lower section of the rock more than the upper part. Therefore, such rocks have a narrower base and a wider top. When the wind blows, it lifts and transports sand from one place to another.

When the wind stops blowing the sand falls and gets deposited in low hill-like structures. These are called sand dunes. When the grains are very fine and light, the wind can carry it over long distances. When such sand is deposited in a large area, it is called loess.

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Our Changing Earth Class 7 Notes PDF Download (Handwritten & Short Notes)

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• Visit the Selfstudys website. 

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• Can Enhance Thinking Skills: With the help of Our Changing Earth Class 7 notes PDF, students can enhance their thinking skills and the same can be implemented in real life.  
• Promotes Active Learning: It is very important for students to be active during the learning process; they can actively be involved in the classroom study with the help of Our Changing Earth Class 7 notes PDF download. 
• Enhances Writing Skills: The Class 7 notes of Our Changing Earth improvises writing skills as the topics are explained in step by step manner. 
• Increases Innovative Skills: With the help of Our Changing Earth notes, students can expand their ability to expand their ideas in an innovative way. 
• Increases Productivity: Going through the Our Changing Earth Class 7 notes, students can increase their productivity: how efficiently a person can complete the work in terms of studying. 

Tips to Cover the Chapter With the Help of Our Changing Earth Class 7 Notes

Every student have their own preferences to cover the chapter with the help of Our Changing Earth Class 7 notes, below are some general guidelines that can be followed: 

• Create Study Environment: Students need to create their own study environment which is different from the usual place so that they can cover the chapter Our Changing Earth with the help of notes. Through this students can avoid unnecessary distractions and allow them to focus fully on the Class 7 Our Changing Earth notes. 
• Explore Different Learning Style: It is important for students to explore different learning styles: make flashcards, use textbooks, use Our Changing Earth Class 7 notes PDF and practise regularly. By adapting a convenient learning style, students can score well in questions related to the chapter Our Changing Earth. 
• Make a Study Plan: Students are advised to make a list of what needs to be covered in the chapter Our Changing Earth and need to make a study plan accordingly. A proper student can easily cover the concepts included in the Our Changing Earth Class 7 notes PDF. 
• Divide the Days into Segments: It is a must for students to divide the days to segments to complete the chapter Our Changing Earth with the help of Class 7 NCERT notes, through this they can take regular breaks. 
• Make Key Points: While completing the Our Changing Earth Class 7 notes PDF download, students can make key points in a separate notebook. Through key points, students can revise the chapter Our Changing Earth during the last minute. 
• Practise Questions: After completing the Our Changing Earth notes, students can definitely practise plenty of questions. By practising a vast amount of questions, students can improve their confidence level during preparation. 

What is the Right Time to Look Through Our Changing Earth Class 7 Notes?

The right time to look through the Our Changing Earth Class 7 notes depends on various factors: learning style, schedule and academic goals, but students need to know the general guidelines like when to look through the notes that are discussed below:

• Before Class: Students can look through the Class 7 Our Changing Earth notes before attending the class, it can help them to be prepared before. This can also make the learning process for students easier while completing the chapter Our Changing Earth. 
• After Class: Immediately after attending the class, students can look through the Our Changing Earth Class 7 notes PDF, this can improve the understanding towards the chapter.  
• While Preparing: Students can look through the notes of Our Changing Earth while preparing for the chapter so that they can keep track of their progress as well as preparation. 
• Before Exams: Students can go through the Our Changing Earth Class 7 notes PDF download before the board exam, so that they can revise all the concepts and topics. 

Impact of Our Changing Earth Class 7 Notes in the Preparation

The Our Changing Earth Class 7 notes can have a major impact on the preparation of board exam and are discussed below: 

• Comprehensive Coverage of the Topic: Through the Class 7 Our Changing Earth notes, students can have a comprehensive coverage and deep understanding of all the topics.
• Can Remember Important Dates: With the help of Our Changing Earth Class 7 notes PDF, students can remember the important dates and can implement it in the board exam. 
• Can Clarify Doubts: The concepts in the Class 7 notes of Our Changing Earth are explained in a clear and concise manner so that students can clarify all doubts. 
• Structured Learning: The Our Changing Earth Class 7 notes PDF are structured in organised manner so that students can easily learn the concepts and topics. Through this, students can divide the chapter Our Changing Earth into segments so that students can improve their understanding. 
• Have a Routine Practice of Questions: After completing the Our Changing Earth with the help of Class 7 Social Science Notes , students can practise plenty of questions. By practising plenty of questions, students can develop their knowledge as well as exam taking skills towards the chapter Our Changing Earth. 
• Saves the Time: The Our Changing Earth Class 7 notes PDF download can save students time to create structured notes as these PDFs are ready made study material, this can have a major impact on students preparation. 

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Earth's Changing Climate

Climate change is a long-term shift in global or regional climate patterns. Often climate change refers specifically to the rise in global temperatures from the mid 20th century to present.

Earth Science, Geography, Human Geography, Physical Geography

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Climate is the long-term pattern of weather in a particular area. Weather can change from hour to hour, day to day, month to month or even from year to year. Climate refers to what the weather is generally like over 30 years or more. A desert might experience a rainy week, but over the long term, it receives very little rainfall . It has a dry climate .

Living things adjust to climates. Polar bears ( Ursus maritimus ) have adjusted to stay warm in polar climates . Over time, cacti have evolved to hold onto water in dry climates. The number of different kinds of life on Earth is partially due to the number of different climates.

Climates do change. They just change very slowly, over hundreds or even thousands of years. As climates change, organisms that live in the area must adjust, relocate , or risk dying out.

Earth's climate has changed many times. For example, fossils from the Cretaceous period (144 million to 65 million years ago) show that Earth was much warmer than it is today. Breadfruit ( Artocarpus altilis —also called "jackfruit"—trees are now found on tropical islands . However, millions of years ago they even grew on Greenland.

Earth has also experienced several major ice ages . There have been at least four in the past 500,000 years. During these periods, Earth's temperature decreased , causing ice sheets and glaciers to expand. The most recent ice age began about two million years ago and only started ending about 18,000 years ago.

Warmer temperatures have caused the glaciers to shrink. The glaciers have not disappeared completely, however—they still exist in Antarctica and Greenland. Scientists think we live in an " interglacial period ," or a time between glaciers. They have gone away somewhat for now, but hundreds of years from now, the glaciers may grow again.

Scientists who study climate look for proof of past climate change in many different places. Like clumsy criminals, glaciers leave many clues behind. They scratch and rub rocks as they move. They leave little bits of material behind known as "glacial till ." This sometimes forms mounds or ridges. Glaciers also form long, oval-shaped hills. If you see a piece of land with any of these signs, it suggests that a glacier was once there.

Some types of rocks only form from materials left behind from glaciers. When scientists find these rocks, it tells them that glaciers were once there.

Scientists also have proof of glaciers from fossils . Fossils show what kinds of animals and plants lived in certain areas. Looking for fossils of animals that lived in the cold can show scientists how far across the planet the glaciers reached.

Climate changes happen over shorter periods, as well. For example, there was a " Little Ice Age " that lasted only a few hundred years. It peaked during the 1500s and 1600s. During this time, average temperatures around the world were two to three degrees Fahrenheit cooler (about one to 1.5 degrees Celsius) than they are today. A change of one or two degrees might not seem like much, but it was enough to cause major changes. Glaciers grew larger and sometimes engulfed whole mountain villages. Winters were longer than usual, limiting the growing seasons of crops . In northern Europe, people left their farms and villages to avoid starving.

One way scientists have learned about the Little Ice Age is by studying the rings of trees. The thickness of tree rings is related to how much the tree grew each year. During times when it was very dry or very cold, trees could not grow as much and rings would be closer together.

Some climate changes are almost predictable . El Niño , which means "The Child" in Spanish, is a good example of this. El Niño refers to the warming of the surface waters in the Pacific Ocean around the equator . In normal years, winds blow across the ocean from east to west. This drags warm water along in the same direction.

Every few years, normal winds change and ocean currents reverse. This is El Niño . Warm water deepens in the eastern Pacific, near South America. This, in turn, produces big climate changes . Rain decreases in Australia and southern Asia, and crazy storms may pound Pacific islands and the west coast of the Americas. Within a year or two, El Niño ends, and climate systems return to normal.

Natural Causes of Climate Change

Climate changes happen for many reasons. Some of these reasons have to do with Earth's atmosphere . The climate change brought by El Niño , which relies on winds and ocean currents , is an example of natural changes in the atmosphere .

Natural climate change can also be affected by forces outside Earth's atmosphere . Earth's relationship to the sun also affects climate . This includes how Earth is tilted and how it orbits around the sun. These change slowly over time and affect how much of the sun's light reaches different parts of the world at different times. The 100,000-year cycles of ice ages are most likely caused by changes in these things.

Large meteorites hitting Earth could also cause climate change . If a meteor hit Earth, it would send millions of tons of dirt and dust into the atmosphere . This would block some of the sun's rays, making it cold and dark. Many plants and animals would die. Many paleontologists believe that dinosaurs went extinct partially due to a meteor or comet hitting Earth. Dinosaurs could not survive in a cool, dark climate . Their bodies could not adjust to the cold, and the dark killed many plants that they ate. Without the plants , the plant -eating dinosaurs died. And without those plant -eating dinosaurs , the dinosaurs that ate them died too.

Plate tectonics also play a role in climate changes . Earth is made of many layers. The top part is the crust, and just beneath that is the mantle. Together, these make up the "plates" in plate tectonics . We now know there are 15 major plates that cover the planet's surface. They move about as fast as our fingernails grow.

Earth's continental plates have moved a great deal over time. More than 200 million years ago, the continents were merged together as one giant landmass called Pangaea . As the continents broke apart and moved, their positions on Earth changed. The movements of ocean currents also changed. Both of these changes affected climate .

Another cause of climate change is called the greenhouse effect . The greenhouse effect happens when gases like carbon dioxide trap the sun's heat in the atmosphere . Gases that do this are called greenhouse gases . They keep Earth warm. Without any greenhouse gases in the atmosphere , most life on Earth would freeze to death. However, adding too much of these gases to the atmosphere slowly makes the planet warmer.

Human Causes of Climate Change

Some human activities release greenhouse gases . For example, humans burn fossil fuels such as coal , oil and natural gas . People often use them for transportation and electricity . Burning fossil fuels releases greenhouse gases , like carbon dioxide . Trees soak up carbon dioxide , so cutting down forests also adds to the greenhouse effect . Factories send greenhouse gases into the atmosphere too.

Many scientists are worried that these activities are causing dangerous changes in Earth's climate . Average temperatures around the world have risen since about 1880. The seven warmest years of the 1900s happened in the 1990s. This warming trend may be a sign that the greenhouse effect is increasing because of human activity. This is often referred to as " global warming ." It is estimated that humans have increased the amount of carbon dioxide in the atmosphere by about 30 percent in the past 150 years.

Other greenhouse gases are increasing, as well. Methane is an example. Methane is a greenhouse gas produced by rotting plants and animals . As populations grow, they use more goods and throw away more. Large landfills , filled with rotting waste, release tons of methane into the atmosphere .

Some chemicals that are used in refrigeration, air conditioning, and aerosol sprays are also greenhouse gases. Many countries are working to get rid of them. Some have laws to prevent companies from manufacturing them.

Global Warming

As the amount of greenhouse gases in the atmosphere rises, so does the temperature of Earth. Scientists worry that the temperature will increase so much that ice caps will begin seriously melting within the next several decades . This would cause the sea level to rise. Coastal areas and small islands would be flooded. Severe climate change may bring more severe weather patterns . This could include more hurricanes , typhoons , and tornadoes . More rain and snow would fall in some places and far less in others. Places where crops now grow could become deserts .

As climates change, so do the homes for many living things. Animals may not be able to survive in their current homes. Many human societies depend on specific crops for food , clothing, and trade . If the climate of an area changes, the same crops may not grow. Some scientists worry that as the planet warms, tropical diseases will spread further.

The temperature will continue to rise unless steps are taken to stop it. Most scientists agree that we must reduce the amount of greenhouse gases released into the atmosphere. There are many ways to do this, including:

• Drive less. Use public transportation , carpool , walk, or ride a bike.
• Fly less. Airplanes produce huge amounts of greenhouse gas emissions .
• Reduce, reuse, and recycle.
• Plant a tree. Trees soak up carbon dioxide, keeping it out of the atmosphere.
• Use less electricity.
• Eat less meat. Cows are one of the biggest methane producers.
• Support alternative power sources that don't burn fossil fuels. These include power that comes from the sun and from wind.

The climate has changed many times during Earth's history. However, those changes have happened slowly, over thousands of years. Only since the Industrial Revolution have human activities begun to influence climate. Scientists are still working to understand what the consequences might be.

Cool Warming Could the current phase of climate change cause another Little Ice Age? As strange as it sounds, some scientists believe it could. If melting glaciers release large amounts of freshwater into the oceans, this could disrupt the ocean conveyor belt, an important circulation system that moves seawater around the globe. Stopping this cycle could possibly cause cooling of 3 to 5 degrees Celsius (5-9 degrees Fahrenheit) in the ocean and atmosphere.

Early Squirrels The North American red squirrel has started breeding earlier in the year as a result of climate change. Food becomes available to the squirrels earlier because of warmer winters.

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CBSE Class 7 Social Science Geography Our Changing Earth Worksheets

CBSE Class 7 Social Science Our Changing Earth Worksheets – In the present education system, Worksheets are playing an important role. Worksheets are very useful for every student in order to practice all the topics of the subject in a concise way. CBSE Class 7 Social Science worksheets for Our Changing Earth are prepared by the experts of WorksheetsBuddy.com as per their latest syllabus and its guidelines. For students who are pursuing CBSE Class 7, can also avail the officials released Worksheets for various subjects. Teachers and students both can get the Chapterwise CBSE NCERT Class 7 Worksheets for all subjects like Social Science, etc. from our site.

But today we have come up with CBSE 7th Standard Social Science Our Changing Earth Worksheets to help students to develop logical, lingual, analytical, and problem-solving capabilities in this topic. So, here we are with a bundle of Social Science Worksheets on this important topic i.e., Our Changing Earth for CBSE Class 7th Students. You can download these Class 7 CBSE Social Science Our Changing Earth Worksheets in PDF format from the further sections.

CBSE Class 7 Social Science Our Changing Earth Worksheets PDF Download

Explore all important concepts of the Our Changing Earth by using these CBSE Class 7 Social Science Our Changing Earth Worksheets Pdf. However, NCERT CBSE Worksheets for Class 7 Social Science chapter wise are prepared by our expertise subject teachers based on the latest CBSE Social Science Syllabus & guidelines released by the CBSE board. With the help of our CBSE NCERT Social Science Our Changing Earth Practice Worksheets , students can easily practice the topic in detail and estimate their preparation level and topic knowledge before the exams.

Our Changing Earth Multiple Choice Questions (MCQs)

1. Longitudinal earthquake wave is the other name of: (a) ‘S’wave (b) ‘O’wave (c) ‘L’ wave (d) ‘P’ wave

2. Which of the following forces work on the surface of the Earth? (a) Exogeinc (b) Endogenic (c) Gravitational (d) Earthquake

3. Which of the given magnitude of earthquake is considered as a major earthquake? (a) 6.0 (b) 5.0 (c) 2.0 (d) 7.0

4. Meanders are features formed by the work of: (a) River (b) Wave (c) Ice (d) Wind

5. Deltas are formed at the (a) Mouth of a river (b) Nose of a river (c) Eyes of a river (d) Ear of a river

Our Changing Earth Fill in the Blanks

1. Plates move due to the movement of ……………. . 2. The place of origin of the earthquake is called ……………. . 3. A ……………. is a vent in the earth’s crust through which molten material erupts suddenly. ‘ 4. Movements of the plates causes changes on the ……………. of the Earth. 5. Wearing away of landscape by different agents is known as ……………. . 6. Landscape is worn away by ……………. and ……………. . 7. Niagra falls is located in ……………. . 8. Victoria falls is located in ……………. . 9. The running water in the river erodes the ……………. . 10. The erosion and depositions of the sea waves gives’rise to different ……………. .

Our Changing Earth Very Short Answer Type Questions

1. What is a flood plain? 2. Name the two forces that are responsible for Earth’s movement. 3. Name the measuring instrument of an earthquake. 4. What is the common earthquake prediction method? 5. Where does the greatest damage occur during an earthquake?

Our Changing Earth Short Answer Type Questions

1. What are the effects of earthquake on the landform? 2. Define tectonic plates. 3. How is a delta formed? 4. What is a waterfall?

Our Changing Earth Long Answer Type Questions

1. How can you be prepared for an earthquake? 2. Why are flood plains fertile?

FAQs on CBSE Social Science Chapterwise Worksheets for Class 7

1. Can CBSE Provide Class 7 Social Science Worksheets for all Chapters?

Yes, CBSE Boards prescribe the Worksheets for Class 7 students on its official website. You can also get them from our website WorksheetsBuddy.com.

2. How can I prepare the Class 7 Social Science Our Changing Earth topic in a fun-learning way?

Practicing NCERT CBSE Class 7 Social Science Our Changing Earth Worksheets is the best way to prepare the concept in detail and in a fun learning way.

3. Which website provides the best Worksheets for Class 7 Social Science chapter wise CBSE?

WorksheetsBuddy website provides the best & most reliable practice Worksheets for CBSE Class 7 Social Science for all chapters like Our Changing Earth, etc.

4. How to download PDF Formatted CBSE NCERT Social Science Our Changing Earth Practice Workbooks for Class 7?

Simply click on the direct links provided on this page and download the CBSE Class 7 Social Science Our Changing Earth Worksheets in PDF format and use them offline at any time anywhere you wish.

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Elementary Teaching Blog

Last updated by Linda Kamp on December 9, 2022 • 7 Comments

10 Hands-On Activities for Teaching Earth Changes & Landforms

Two favorite second grade science topics each year are Earth Changes and Landforms. Always a highlight, students learn about erosion, weathering, deposition and many different landforms. Here are 10 hands-on landforms and earth changes activities for teaching fast and slow earth changes in 2nd grade science.

Landforms Activities

Each of these activities is available in a complete Earth Changes 2nd grade science unit . Some activities are available in digital format .

Describe Earth’s Land

Introduce your students to the different features of the Earth’s land and surface. Describe the different types of landforms on Earth and the variety of ways they are formed. Ask students, “What landforms have you seen in a place you have visited or where you live?”.

Show videos to help introduce different the types of landforms and how they form on Earth.

Landforms, Hey! (3:57)

Exploring Landforms and Bodies of Water (9:18)

Name That Landform

Play a partner game with Play Doh. Have two students play together. Each uses Play Doh to make a landform. They then check of features of their model on their recording page.  Next, students draw a diagram of their landform model.

Lastly, and before showing it to their partner, the each students take turns describing the features of their landform and asks their partner to guess which landform they made based on the features they heard described. This simple activity gives students practice in describing an object and drawing and labeling a diagram.

Salt Dough Landform Islands

In this project, students show the kinds of land and water in a make believe area by making landform islands.  We have used both salt dough and Crayola Air Dry Clay. Students make a model of a special area they design that features several landforms and bodies of water.

I use blue paper plates from the dollar store and Crayola Air Dry Clay from Walmart or any craft store. I recommend doing this project on a Friday and allowing them to dry over the weekend. Students can then paint their islands using Tempra or acrylic paint.

Extend the project and address multiple standards by having students make maps and measure distances between landforms or points on their islands.

Make a Topographical Map

How do engineers map the height of a mountain? In this activity, students use clay to make a 3-D model, then section it to make a topographical map. Making this type of map is a fun way to incorporate not only map skills, but math practices.

Students begin by making a simple model of a mountain out of clay. We used Crayola Air Dry Clay.  Next, they use dental floss to section their model into equal slices. Guide students to understand that a topographic map is another type of model. It is a one-dimensional model that shows heights using numbers and curved lines.

This video, Understanding Topographical Maps is a good one to demonstrate how to use clay and dental floss to make a topographic map.

Earth Changes Activities

Fast earth changes.

Some changes to the Earth’s surface happen rapidly. Events like earthquakes, tsunamis, volcanic eruptions, and landslides all happen very quickly with a series of events preceding them. But what causes land to change quickly?

These videos explain the science behind rapid and sudden changes to the Earth’s land and surface.

• Floods (3:48)
• Landslides (3:18)
• Earthquakes (3:46)
• Tsunamis (3:37)

Engineer a Solution to Prevent Landslides

Another fun earth changes activity to do is to simulate a landslide. Show the above landslide video to students and discuss the causes of a landslide and how people can help to prevent them. Challenge students to simulate a landslide then design a solution to help prevent a landslide and protect a community.

We used crumpled newspaper covered in potting soil to create a slope. We simulated a landslide of the slope with no vegetation by pouring water on the hill to represent a heavy rain storm.. Next, students did the simulation again with vegetation (aquarium plants) strategically placed to help hold the soil in place.

Students observe and record the amount of water they use before their slope begins to slide each time. They also measured and compared the distance their houses slid down the slope with and without surrounding vegetation.

Slow Earth Changes

Save a lighthouse from water erosion.

Save the Lighthouse! is a fun teaching lab to simulate the erosion of a coastline. Students first simulate ocean waves eroding a coastline.

They then use craft sticks, craft foam, rocks, screen and whatever materials they decide upon, to design ways to prevent the erosion to save the lighthouse.

Design a Windbreak to Prevent Wind Erosion

Another type of erosion we learn about in 2nd grade is wind erosion. Students learn the damaging effect that wind can have on crop fields.

After learning about ways farmers use trees and shrubs to build windbreaks to protect their fields, students are tasked with designing their own. When designing their windbreaks, students first need to consider wind direction. They should also consider if there are existing structures nearby that might also serve to block wind.

Students design a simple windbreak using paper trees, cotton balls, and a straw to simulate wind blowing soil and how the windbreak stops wind erosion and damage to a crop field. Under the “crop field” is a lab sheet booklet for students to draw a diagram of their design and explain the things they took into consideration that informed their designs.

Solve Science Word Problems

So many of these activities lend themselves well to applying math skills. Adding, subtracting, measuring, and comparing lengths are easily included when students are making maps, building models, and conducting investigations.

Solving word problems that use science content gives students not only math and reading practice, but also an opportunity to apply what they have learned about landforms and earth changes.

Sequence Events that Lead to Earth Changes

Identifying the causes and effects of earth changes helps students to better understand Earth’s processes. This science center tasks students with sequencing the events/causes that lead up to a significant change to the earth’s land.

Shop Landforms & Earth Changes Activities

Preview these science units:

• Landforms & Earth Changes
• Digital Landforms & Earth Changes Activities
• Landforms & Earth Changes BUNDLE

I hope you have found ideas you can use as you plan your own landforms and earth changes activities and lessons. Be sure to pin this post for later so you have it when you plan!

For more second grade science activities, visit these posts:

Properties of Matter Activities

Habitats & Ecosystems Activities

Plant Life Cycle Activities

Happy teaching!

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Reader Interactions

November 5 at 12:31 pm

Hello, I am interested in the handout you show pictured above, “Name that Landform”. Can you please direct me to where I could find that? Thanks!

November 22 at 6:32 am

Hi Sharon, Thanks for reaching out! The “Name that Landform” lab is part of this 2nd grade science unit: https://aroundthekampfire.com/product/landforms-fast-slow-earth-changes-second-grade-science-unit-ngss

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I’m Linda Kamp, a 20 year primary grade teacher with a passion for creating educational materials that excite students and make learning fun! I'm so glad you're here!

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NCERT Solutions Class 7 Social Science Our Environment Chapter 3

Home » NCERT Solutions » NCERT Solutions Class 7 Social Science Our Environment Chapter 3

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Earth’s motions are classified according to the factors that cause them. Endogenic forces operate within the earth’s interior, whereas exogenic forces operate on its surface. Earthquakes and volcanic eruptions wreak havoc on the earth’s surface. Weathering and erosion are two processes that continually erode the terrain. Chapter 3 sheds light on all these important topics. There is a set of questions given at the end of each chapter in the NCERT textbook, and students must solve these questions to understand the concepts in a better way. 

Quick Links

Students can access NCERT Solutions for Class 7 Geography Chapter 3 on Extramarks to get answers to all the textbook questions. The solutions will help students in improving their conceptual understanding and will be able to answer any question asked in the examination no matter how tweaked they are. 

NCERT Solutions for Class 7 Social Science Chapter 3 – Our Changing Earth – Download

Access ncert solutions for class 7 social science (geography) chapter 3 – our changing earth, ncert solutions for class 7 social science download.

The NCERT Solutions are prepared in simple and easy-to-understand language to help students grasp the concepts effectively. The solutions are accessible on the website and app of Extramarks.

An Overview of the NCERT Class 7 Geography Chapter 3 Notes

The notes for Class 7 Geography Chapter 3 cover several areas of Geography. Let’s look at some important topics:

• Lithospheric Plates: The lithosphere is broken into a number of plates called the Lithospheric plates. Because of the movement of molten magma inside the earth, the lithospheric plate gets broken into different plates and continues to move around slowly. 
• The molten magma inside the earth continues to move in a circular motion. These movements are further divided on the basis of endogenic and exogenic factors. Endogenic forces, which occur in the interior, cause unexpected activities that result in earthquakes and volcanic eruptions. Exogenic forces, also known as exogamic forces, work on the surface of the earth. 
• Volcano: A volcano is a vent in the crust of the earth. Molten material comes out of the volcano. 
• Earthquake: When lithospheric plates move, the vibration of the earth travels across, causing earthquakes.
• Epicentre: The epicentre is the point at which the actual movement of lithospheric plates occurs. Waves travel from the epicentre to other locations.

Major Landforms:

The chapter provides detailed information about how the landscape wears out through two different processes: weathering and erosion.The breaking up of rocks on the earth’s surface is referred to as weathering.

• Erosion is the process of the terrain getting eroded by various factors such as water, wind, and ice. Water and wind carry away the eroded material. Different landforms are formed due to the processes of erosion and deposition.

Work of Sea Waves

Changes in sea waves also contribute to a changing ecosystem. Here are some ways  sea waves change:

• Sea Caves: Coastal landforms are formed due to erosion and deposition, which also keep rocks from striking each other and lead to cracks. These cracks keep on growing over time, creating caves.
• Sea Arches: When cavities in the rock get larger, arches form.
• Sea Cliff: Seacliff is a steep rocky coast that rises vertically and in different shapes.

Work of Wind

Aside from the water and the land, the wind also plays a major role in modifying landforms. The wind blowing in the desert is an active agent of erosion and deposition. On the other hand, sand dunes are formed when the wind carries sand from one location to another. When the wind stops blowing, the sand settles down. This area is called sand dunes.

Class 7 Geography Chapter 3 Notes

NCERT Class 7 Geography Chapter 3 notes are now available on Extramarks, which makes learning simple and more effective.. The solutions provide accurate information about a specific topic ,which allows students to gain in-depth knowledge.

NCERT Class 7 Social Science Our Environment Chapterwise Solutions

Extramarks provides the following NCERT Class 7 Social Science Chapter wise Solutions:

• Chapter 1 – Environment
• Chapter 2 – Inside Our Earth
• Chapter 3 – Our Changing Earth
• Chapter 4 – Air
• Chapter 5 – Water
• Chapter 6 – Natural Vegetation and Wildlife
• Chapter 7 – Human Environment-Settlement, Transport and Communication
• Chapter 8 – Human Environment Interactions – The Tropical and the Subtropical Region
• Chapter 9 –  Life in the Deserts

NCERT Solutions for Class 7 Social Science

NCERT Solutions for Class 7 Social Science have the most appropriate answers to all of the questions from the Social Science textbook. The study materials include clear explanations and comprehensive discussions. Academic experts with years of experience have prepared these solutions as per the  NCERT books while adhering to the recent CBSE syllabus. 

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Q.1 Observe the photographs given below. These are various features made by a river. Identify them and also tell whether they are erosional or depositional or landforms formed by both.

Q.2 Answer the following questions. (i) Why do the plates move? (ii) What are exogenic and endogenic forces? (iii) What is erosion? (iv) How are flood plains formed? (v) What are sand dunes? (vi) How are beaches formed? (vii) What are ox bow lakes?

(i) Plates move because of the movement of molten magma inside the earth. The molten magma moves inside the earth in a circular manner.

(ii)The forces which act on the surface of the earth are known as exogenic forces, whereas the forces which act in the interior of the earth are known as endogenic forces.

(iii)The wearing away of landscape by different agent of nature like wind, water, and ice is known as erosion.

(iv) Layers of fine soil and other materials known as sediments are deposited along the banks of river, whenever a river floods. This leads to the formation of a fertile floodplain.

(v) When the wind blows in a desert, it transports sand from one place to another. When it stops blowing, the sand falls and gets deposited in low hill-like structures, which are known as sand dunes.

(vi) Beaches are formed when sediments carried by the sea waves are deposited along the shores. The finer sediments are deposited near the sea, while the coarser ones are deposited further inland.

(vii) Rivers start meandering when they enter the plains. In due course of time, the meander loop cuts off from the river and forms a cut-off lake, which is also known as an ox bow lake.

Q.3 Tick the correct answer.

(i) Which is not an erosional feature of sea waves? (a) Cliff (b) Beach (c) Sea cave

(ii) The depositional feature of a glacier is: (a) Flood plain (b) Beach (c) Moraine

(iii) Which is caused by the sudden movements of the earth? (a) Volcano (b) Folding (c) Flood plain

(iv) Mushroom rocks are found in: (a) Deserts (b) River valleys (c) Glaciers

(v) Ox bow lakes are found in: (a) Glaciers (b) River valleys (c) Deserts

(i) (b) Beach ✓ (ii) (c) Moraine ✓ (iii) (a) Volcano ✓ (iv) (a) Deserts ✓ (v) (b) River valleys ✓

Q.4 Match the following.

Q.6 Solve the crossword puzzle with the help of given clues.

2. Loop like the bend of a river

4. Solid form of water

7. Moving mass of ice

9. Sudden descent of water in the bed of a river

11. Natural cavity on weak rocks formed by the action of waves

12. Embankment on a river that keeps it in its channel

13. Large body of water

14. Dry area where sand dunes are found

15. Small hill of sand caused by the action of wind

16. Flat plain formed by river deposits during time of flood

1. Rise and fall of water caused by friction of wind on water surface

3. Flow of water in a channel

5. Steep perpendicular face of a rock along a sea coast

6. Debris of boulder and coarse material carried by glacier

8. Crescent shaped lake formed by a meandering river

10. Fine sand deposited by the action of wind

13. Isolated mass of rising steep rock near a coastline

14. Alluvial tracts of land formed by the river deposits at the mouth of a river

2. Loop like the bend of a river: Meander

4. Solid form of water: Ice

7. Moving mass of ice: Glacier

9. Sudden descent of water in the bed of a river: Waterfall

11. Natural cavity on weak rocks formed by the action of waves: Cave

12. Embankment on a river that keeps it in its channel: Levee

13. Large body of water: Sea

14. Dry area where sand dunes are found: Desert

15. Small hill of sand caused by the action of wind: Sand dune

16. Flat plain formed by river deposits during time of flood: Floodplain

1. Rise and fall of water caused by friction of wind on water surface: Wave

3. Flow of water in a channel: River

5. Steep perpendicular face of a rock along a sea coast: Cliff

6. Debris of boulder and coarse material carried by glacier: Moraine

8. Crescent shaped lake formed by a meandering river: Oxbow lake

10. Fine sand deposited by the action of wind: Loess

13. Isolated mass of rising steep rock near a coastline: Stack

14. Alluvial tracts of land formed by the river deposits at the mouth of a river: Delta

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Faqs (frequently asked questions), 1. what are the different types of forces on earth.

There are many types of forces on earth. Chapter 3 discusses how the movement of the earth is divided on the bases of the two forces – endogenic and exogenic. Endogenic forces work within the earth’s interior, while exogenic factors function on its surface. These endogenic pressures frequently cause abrupt movements, but they can also cause sluggish movements. Volcanoes form as a result of these rapid movements.

2. What are the coastal processes?

The coastal zone is a portion of the land surface heavily impacted by maritime processes. Coastal zones have an active role on the earth’s surface, producing coastal rocks, beaches, and dunes as well as marine and atmospheric processes. Mangroves, coral reefs, and salt marshes are all found along these beaches. The wind blows in the ocean, which causes waves to form. The longer the waves pick, the stronger the wind.

3. According to Chapter 3 of Social Science Class 7, what do you know about the lithospheric plates?

Lithospheric plates are formed when areas of the earth’s crust and upper mantle of the lithosphere are broken into multiple plates. These plates move slowly due to the flow of molten magma within the earth’s crust. The movement of these lithospheric plates is responsible for all of the changes on  Earth’s surface. Volcanoes, earthquakes, and other natural disasters are caused by the sudden movements of these lithospheric plates.

4. How do the lithospheric plates move?

The heat is created in the earth’s core as convection currents in the mantle cause movement in the lithospheric plates. When the warmer material rises, the colder material descends. This process of rising and sinking keeps repeating itself, causing the lithospheric plates to rise and become the reason for their movement.

5. Explain how a river works, as described in Chapter 3 of Social Science for Class 7?

The flowing water of the river erodes the landscape. A waterfall is formed when a river rushes at a steep angle over hard rocks or down a deep valley side. Due to continual erosion and deposition along the meander’s sides, the ends of the meander loop get closer and closer.

The cut-off lake, also known as an ox-bow lake, is formed when the meander loop splits from the river. When the river overflows its banks, flooding occurs in the surrounding areas. As it floods, it dumps sediments, which are layers of fine dirt and other debris, along its banks.

6. Give an account of earthquake preparedness based on chapter 3 of Social Science Class 7.

An earthquake is a natural tragedy that we cannot avert. We may, however, decrease the impact if we are prepared ahead of time. During an earthquake, we should always evacuate to a safe spot. We should hide behind a kitchen counter, table, or desk against a door or a wall. Fireplaces, areas near chimneys, and windows with reflective surfaces, such as mirrors and picture frames, should all be avoided. 

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• Preparatory

Lesson Plan: Solutions to a Changing Earth

This lesson plan includes the objectives and prerequisites of the lesson teaching students how to identify ways that human activities impact erosion, and recognize and design solutions to slow and prevent erosion.

Students will be able to

• understand that erosion is caused by wind and water,
• describe how humans making changes to land, like cutting down trees, impacts erosion,
• describe how humans making changes to water, like building dams, impacts erosion,
• describe and identify solutions to erosion like dikes, levees, and windbreaks,
• test and compare multiple solutions to a problem caused by erosion.

Prerequisites

Students should already be familiar with

• slow changes to Earth’s surface including erosion, weathering, and deposition.

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The Ocean and Climate Change

Our ocean is changing. With 70 percent of the planet covered in water, the seas are important drivers of the global climate. Yet increasing greenhouse gases from human activities are altering the ocean before our eyes. NASA and its partners are on a mission to find out more.

The ocean is warming

Rising greenhouse gas concentrations not only warm the air, but the ocean, too. Research shows that around 90 percent of the excess heat from global warming is being absorbed by the ocean. Ocean heat has steadily risen since measurements began in 1955, breaking records in 2023 . All this added heat has led to more frequent and intense marine heat waves. The image visualizes sea surface temperature anomalies in August 2023. Warm colors (red, orange) show where the ocean was warmer than normal. Cool colors (blues) show where temperatures were cooler. The red swath in the Eastern Pacific was due to an El Niño event. El Niño is a climate phenomenon in the tropical Pacific that results in warmer than normal sea surface temperatures leading to weather impacts across the planet. Credit: NASA

Sea levels are rising

Global sea levels have risen more than 4 inches (101 millimeters) since measurements began in 1992, increasing coastal flooding in some places. As ocean water warms, it expands and takes up more space. The added heat in the air and ocean is also melting ice sheets and glaciers, which adds freshwater to the ocean and further raises sea levels. The Surface Water and Ocean Topography (SWOT) mission , launched in 2022, and Sentinel 6 Michael Freilich , launched in 2020, are providing unparalleled views of sea level rise on top of decades of data from other missions. The video shows a 21-day average of sea surface height anomalies highlighting ocean eddies and currents as imaged by the Surface Water and Ocean Topography (SWOT) satellite. The red and orange colors indicate where the sea surface was higher than normal and the blues are where it was lower than normal. Credit: NAS

Explore Earth's Vital Signs

The ocean is getting a little greener

Recent research found that over the past 20 years, the tropical ocean turned greener. Ocean color reflects the life that is found in it. Green colors often correspond to phytoplankton, microscopic plant-like organisms that form the center of the ocean's food web. Observations of changes in phytoplankton populations due to climate change are a key part of the Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE) mission , which launched in 2024.

Ocean warming is altering hurricanes

Hurricanes need warm water to form and strengthen. Recent research points to warmer ocean temperatures as a key factor causing more storms to rapidly intensify. One way to detect rapid intensification before it happens may be through a change in lightning around the eye of the storm. Plus, higher sea levels worsen storm surge flooding when a storm travels over a coastline. NOAA’s GOES-East satellite captures the rapid intensification of Hurricane Lee on Sept. 7, 2023.  Credit: NASA/NOAA

Ocean acidification and heating are altering marine ecosystems

Carbon dioxide and heat are both absorbed by the ocean as greenhouse gas levels increase. When carbon dioxide is dissolved in the ocean, the water becomes more acidic. This makes it harder for corals and some other marine life to grow shells and protect themselves. Marine heat waves are complicating the matter by making it too warm for many corals to survive. Satellites are providing important data to scientists measuring such changes in ocean environments. When corals are stressed from changes in their environment, they turn white, or "bleach." Sometimes the coral is able to recover, but other times the bleaching event leads to its death. This image shows the decay of a healthy coral reef to a reef between 2014 and 2015 in the National Marine Sanctuary of American Samoa. Credit: NOAA/ XL Catlin Seaview Survey

Sea ice is thinning and shrinking

Melting sea ice does not affect sea levels, but it does impact global temperatures. Sea ice is light-colored and reflects sunlight back into space; open water is darker and absorbs more sunlight. Warming ocean waters melt sea ice from below, and warmer air helps melt it from above. As ice cover thins and shrinks, more ocean is exposed and less sunlight is reflected, further warming the water and air. Satellites help monitor changes in sea ice which is an area of research for upcoming missions in the Earth Systems Observatory . A photograph of Arctic sea ice breaking up as seen during an overhead flight during NASA’s Operation IceBridge in March 2011. Credit: NASA

Explore the Earth Systems Observatory

El Niño can add to the heat

El Niño occurs when the central and eastern tropical Pacific Ocean become warmer than normal. This periodic ocean warming can add to the long-term global warming that has already accumulated, making a hot year even hotter. That’s because ocean temperatures are major drivers of global temperatures, as seen in 2023 . A visualization showing sea surface height anomalies in the Pacific Ocean in June 2023 based on satellite data. The red and orange colors show a higher-than-normal sea surface height. The blue areas were lower than normal. Credit: NASA

Read More About 2023's Record Heat

Ocean circulation may be changing

Ocean currents are vital transporters of heat around the planet. As the Greenland and Antarctic ice sheets melt, the excess fresh water running into the ocean could disrupt the balance of temperature and salinity that drive deep ocean currents. NASA satellite mission s are monitoring the ocean for changes in heat transport as glaciers continue to melt and the ocean warms. Clouds trace out islands in the Caribbean Sea in this photo taken by an astronaut aboard the International Space Station.  Credit: NASA

Read More About Ocean Circulation

Key Satellites and Missions

Aqua is collecting data about Earth's water cycle.

Gravity Recovery and Climate Experiment Follow-On (GRACE-FO)

GRACE-FO is tracking Earth’s water movement across the planet.

Sentinel-6 Michael Freilich

Sentinel-6 Michael Freilich is measuring the height of the ocean.

Surface Water and Ocean Topography (SWOT)

SWOT is providing the first global survey of Earth’s surface water and measuring how it is changing over time.

Plankton, Aerosol, Cloud, and ocean Ecosystem (PACE)

PACE is measuring key variables related to cloud formation, particles and pollutants in the air, and microscopic, floating marine life.

Earth System Observatory

NASA’s Earth System Observatory is a series of satellites working in tandem to create a 3D, holistic view of Earth, from bedrock to atmosphere.

Latest News and Research

Nasa mission flies over arctic to study sea ice melt causes.

How NASA Spotted El Niño Changing the Saltiness of Coastal Waters

Vanishing corals: nasa data helps track coral reefs.

Is the Wilkins Ice Shelf Weakening?

Key ocean and climate resources.

NASA Sea Level Change

NASA’s Sea Level Change portal provides key data, stories, and tools related to NASA’s sea level research.

NASA Earthdata - Ocean

NASA’s Earthdata provides open access to ocean and other datasets produced by NASA satellites and its partners.

Estimating Circulation and Climate of the Ocean (ECCO) Consortium

ECCO combines state-of-the-art ocean circulation models with global ocean datasets to estimate ocean circulation and its role in the climate.

State of the Ocean on NASA Worldview

NASA Worldview State of the Ocean visualizes real data from satellites to show sea surface temperatures and anomalies, and chlorophyll on a daily basis.

Ocean Color

Ocean Color provides key data, stories, and tools related to NASA’s Ocean Biology Processing Group’s research.

Climate Kids

The ocean covers about 70% of Earth’s surface. So, it’s not surprising that it plays a large part in Earth’s environment. As Earth warms, water in the ocean soaks up energy (heat) and distributes it more evenly across the planet. The ocean also absorbs carbon dioxide from Earth’s atmosphere. The additional heat and carbon dioxide in the ocean can change the environment for the many plants and animals that live there.

Have an account?

Our Changing Earth

Social studies.

10 questions

Introducing new   Paper mode

No student devices needed.   Know more

What is the study of earthquakes called?

Seismologists

Seismograph

Which of the following the definition of Epicenter?

The point on the surface of the earth where the earthquake starts

The point under the surface where the earthquake starts

The instrument used to record the earthquake waves

The molten state of rocks inside the earth is called........

Metamorphic rocks

Movement of lithospheric plates results in ________ and _________

Endogenic and Exogenic forces

Focus and Epicenter

Crust and trough

Folding and Faulting

Sea waves and ice are____________ forces

Lava flows out of the crater of the volcano

Exogenic forces occur slowly over time

_______is an example of diastrophic forces

Building mountains

Apart from _____forces,the Earth is also continuously subjected to _______forces driven by sunlight and on originating within the Earth’s atmosphere

Internal,external

External,internal

Which of the following are degradational or erosional forces:

deforestation

Pollination

Seed dispersal

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Earth is more than a planet with life on it. It's a "living planet"

Regina G. Barber

Berly McCoy

Rebecca Ramirez

Ferris Jabr's book Becoming Earth: How Our Planet Came to Life examines the ways life and Earth have shaped each other. Lucas Heinrich/Random House hide caption

Ferris Jabr's book Becoming Earth: How Our Planet Came to Life examines the ways life and Earth have shaped each other.

About ten years ago, science writer Ferris Jabr started contemplating Earth as a living planet rather than a planet with life on it . It began when he learned that the Amazon rainforest doesn't simply receive the rain that gives it its namesake; rather, it helps generate that rain. The Amazon does that by launching bits of biological confetti into the atmosphere that, in turn, seed clouds.

He began looking for other ways life changes its environment, which led to his new book Becoming Earth: How Our Planet Came to Life . He talks to host Regina G. Barber about examples of how life transformed the planet — from changing the color of our sky to altering the weather.

Have a story about the environment you'd like us to cover? Email us at [email protected].

Listen to Short Wave on Spotify and Apple Podcasts .

Listen to every episode of Short Wave sponsor-free and support our work at NPR by signing up for Short Wave+ at plus.npr.org/shortwave .

This episode was produced and fact checked by Berly McCoy and edited by Rebecca Ramirez. The audio engineer was Kwesi Lee.

FutureVU: Sustainability

Gilligan awarded spot in American Geophysical Union’s Voices for Science program

Posted by hamiltcl on Tuesday, July 2, 2024 in News .

In March, Gilligan was awarded admittance to the American Geophysical Union’s 2024-2025 Voices for Science program to hone their communication and advocacy skills to increase understanding and support of science. The program, which only accepts about 40 fellows, trains scientists to communicate the value of Earth and space science to key decision makers, journalists, and the public, with the hope of solving some of the most critical climate-related challenges facing society.

“Being accepted into the program means a lot to me, because it provides opportunities for training to hone my communication and outreach skills,” Gilligan said. “I am able to explore ways to connect meaningfully with state and local policymakers in Tennessee and in Nashville, including both elected officials and public servants at city and state agencies who really know what happens when the rubber meets the road in implementing environmental policies and initiatives.”

Over the course of 12 months, Gilligan will conduct outreach activities aimed at Tennessee’s general public, business sector, and policymakers to convey the importance of interdisciplinary environmental science, which integrates social and behavioral sciences with natural sciences and engineering, to reduce the negative impacts of climate change and create a more informed public.

Interdisciplinary science is essential to generate new knowledge and drive innovation. Discoveries and advancements often happen at the intersection of multiple scientific fields. This allows researchers to break down nuanced, real-world issues into their respective components, such as examining ways to reduce greenhouse gas emissions while also looking at how that affects socio-economic inequality.

“I am having conversations with people in government to learn more about how they think and to better understand the constraints they face in implementing solutions to the challenges of environmental sustainability and resilience,” Gilligan said. “This will allow me to better connect my research at Vanderbilt to the practical problems they face.”

In a recent study  published in the March 2024 volume of  Energy Policy , Gilligan and other Vanderbilt researchers found that investments in voluntary household actions through the 2021 Infrastructure Investment and Jobs Act and the 2022 Inflation Reduction Act are expected to represent 40 percent of greenhouse gas emission reductions for both laws.

“One important part of this is that individuals and households don’t make decisions in a vacuum,” Gilligan said. “They are influenced by what they see other people—friends, family, neighbors, co-workers, etc.—doing, and if we can harness this interpersonal influence, we could see a rapid acceleration of energy efficiency and emissions reduction in households. I believe that shifting the focus from partisan politics to practical policies that can protect the environment, create jobs, and protect people from increasingly severe weather has potential to break through the gridlock that has paralyzed environmental policy.”

Gilligan joined Vanderbilt’s  Department of Earth and Environmental Sciences  in 2003, where they collaborate on interdisciplinary research focused on interactions between human behavior, society, and environmental change. Gilligan has published one book and more than 100 scholarly articles, and holds two patents.

Gilligan was a recipient of a  2023-24 Fulbright U.S. Scholar Program award , was named Vanderbilt’s  Alexander Heard Distinguished Professor  (2022), and was awarded Vanderbilt’s Margaret Cuninggim Women’s Center  Mentoring Award (2023).

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At michigan state university, msu to expand chip-testing facility at frib to meet critical national need.

Today, the Michigan State University (MSU) Board of Trustees (BOT) authorized construction of a high-bay addition to the west end of FRIB. The addition will triple the testing capacity of the current chip-testing facility by providing two additional user vaults. The K500 Chip Testing Facility at FRIB will help meet the current national shortfall of testing capacity for advanced microelectronics, including those used for commercial spaceflight, wireless technology, and autonomous vehicles.

The 2018 National Academies report, “ Testing at the Speed of Light ,” outlined a critical national shortfall of testing capacity of space-bound electronic components. Supporting the national need for testing capacity, FRIB currently operates the  FRIB Single Events Effects (FSEE) facility , which uses heavy-ion beams to measure the response of electronic components to such ions. This simulates in a few minutes the effect of cosmic rays on electronics over decades of operation.

Cosmic rays are high-energy particles that bombard Earth from all directions in space. These include heavy ions that are known to cause serious issues with the performance and longevity of electronic systems on spacecraft and satellites, as well as electronics on land-based systems such as autonomous vehicles and medical devices.

The federal government awarded $14 million to MSU to establish the K500 Chip Testing Facility, which supports the refurbishment of the world’s first superconducting cyclotron—the  K500 built at MSU in the 1980s —into a heavy-ion chip testing facility.

The addition will also provide student opportunities through  the MSU Space Electronics Center started by FRIB and the MSU College of Engineering. The MSU Space Electronics Center—transitioning to the MSU Space Electronics Initiative—together with the K500 Chip Testing Facility at FRIB will position MSU as a national leader in chip design and testing, and it will provide additional capacity to educate students in chip design and testing. The K500 facility at FRIB will be a magnet for attracting high-tech companies to Michigan, increasing the state’s impact to the nation’s semiconductor and aerospace infrastructure. 

MSU Research Foundation Professor John Papapolymerou will transition from his role as chair of the Department of Electrical and Computer Engineering to the inaugural director role for the MSU Space Electronics Initiative effective 1 July. The change in title from “center” to ‘initiative” addresses the breadth of the aligned efforts toward expanding MSU’s impact in this essential field.

Papapolymerou emphasized that the MSU Space Electronics Initiative promotes collaboration between industry, government, and MSU's faculty, students, and researchers, creating an unparalleled framework that the K500 Chip Testing Facility at FRIB broadens and bolsters. 

"The K500 Chip Testing Facility at FRIB marks a pivotal expansion of our thriving exceptional ecosystem, dedicated to advancing radiation-hardened components and cutting-edge space electronics, and more crucially, to nurturing the next generation of talent essential for sustaining this technology's future and solidifying our nation’s leadership in the field,” said Papapolymerou. "Space electronics applications are poised to inspire a new wave of engineers and scientists, crucial to filling the anticipated 50,000 positions in semiconductor-related fields over the next five years. MSU is positioned at the forefront of molding this critical talent pipeline."

“This is an exciting next step in expanding MSU’s impact in this critical area in service to the nation—both in providing testing capacity and cultivating a skilled workforce,” said MSU College of Engineering Dean Leo Kempel. “By partnering to foster talent and innovation, MSU, FRIB, and the College of Engineering are forging a path that ensures America's leadership in this vital field for generations to come, with Spartan engineers leading the way."

The K500 Chip Testing Facility is an addition to FRIB’s west side, between FRIB and the Chemistry, Biomedical and Physical Sciences, and Biochemistry buildings. Construction is expected to last about 14 months. As part of the construction process, MSU will take the opportunity to better integrate the addition into the MSU campus scenery using vertical greenery, and will incorporate public art into the project.

“Expanding from our current FSEE facility not only enhances our capabilities, but also underscores our commitment to supporting scientific users in their efforts toward advancing our nation's technological resilience,” said FRIB Radiation Effects Facility Manager Steve Lidia. “We are eager to serve more users and support this national need, leveraging the unique capabilities of FRIB in a most essential and impactful way.”

“We are grateful for the continued trust placed in us to operate FRIB and leverage our skilled workforce to deliver significant and synergistic activities like chip testing that serve national needs,” said FRIB Laboratory Director Thomas Glasmacher. “This is truly a testament to the enduring importance of long-term vision and consistent action toward leveraging skills and assets afforded by public investment in FRIB to address new opportunities for the betterment of society.”

  Michigan State University  has been advancing the common good with uncommon will for more than 165 years. One of the world's leading research universities, MSU pushes the boundaries of discovery to make a better, safer, healthier world for all while providing life-changing opportunities to a diverse and inclusive academic community through more than 400 programs of study in 17 degree-granting colleges. 

Michigan State University operates the  Facility for Rare Isotope Beams  as a user facility for the U.S. Department of Energy Office of Science (DOE-SC) with funding from by a cooperative agreement between DOE-SC and MSU, supporting the mission of the DOE-SC Office of Nuclear Physics.

The  U.S. Department of Energy Office of Science  is the single largest supporter of basic research in the physical sciences in the United States and is working to address some of today’s most pressing challenges. For more information, visit  energy.gov/science .

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• CBSE Class 7
• Important Questions For Class 7
• Class 7 Geography Important Questions
• Chapter 3 Our Changing Earth

CBSE Class 7 Geography Chapter 3 Our Changing Earth Important Questions

The lithosphere is broken into a number of plates known as the Lithospheric plates. You will be surprised to know that these plates move around very slowly – just a few millimetres each year. The movement of these plates cause changes on the surface of the earth. Students can explore further about our changing Earth in Chapter 3 of CBSE Class 7 Geography. We have also compiled CBSE Class 7 Geography Chapter 3 Our Changing Earth Important Questions covering major concepts of the Chapter, for the students to answer while preparing for the exam. Practising these important questions will help the students to gain high scores.

Click on the link provided below in this article to download the PDF format of the CBSE Class 7 Social Science Important Questions from Chapter 3 Geography.

• Chapter 1 Environment
• Chapter 2 Inside Our Earth
• Chapter 4 Air
• Chapter 5 Water
• Chapter 6 Natural Vegetation And Wild Life
• Chapter 7 Human Environment Settlement Transport And Communication
• Chapter 8 Human Environment Interactions The Tropical And The Subtropical Region
• Chapter 9 Life In The Deserts

Download CBSE Class 7 Geography Chapter 3 Our Changing Earth Important Questions PDF

Our Changing Earth

1. What are lithospheric plates?

2 . Define Endogenic forces and Exogenic forces.

3 . What is a volcano?

4 . Which are the three types of Earthquake waves?

5 . Why do the plates move?

6. What is erosion?

7. How are flood plains formed?

8 . What are sand dunes?

9 . How are the beaches formed?

10. What are ox bow lakes?

11 . The depositional feature of a glacier is Moraine. True or False?

12 . Some rocks have the shape of a mushroom. Give reasons.

13. Flood plains are very fertile. Explain.

14 . Sea caves are turned into stacks. Justify.

15 . Buildings collapse due to earthquakes. Give reasons.

16 . How does man cause the Earthquake?

17 . What are the two types of tectonic movement?

18. Which are the few rivers of the world that form a delta?

19. Define distributaries.

20. Explain how glacial moraines are formed.

21 . What is the place on the surface above the focus called? (a) focus (b) forces (c) lithosphere (d) epicentre

22. What are the sudden movements of the Earth known as? (a) building mountains (b) force (c) earthquakes (d) none of the above

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China Becomes First Country to Retrieve Rocks From the Moon’s Far Side

The Chang’e-6 mission’s sample, which might hold clues about the origins of the moon and Earth, is the latest achievement of China’s lunar exploration program.

By Katrina Miller

Katrina Miller reported on China’s launch of the Chang’e-6 mission in May.

June 28, 2024: This article was updated to add details about the lunar sample that were announced after its original publication date.

China brought a capsule full of lunar soil from the far side of the moon down to Earth on Tuesday, achieving the latest success in an ambitious schedule to explore the moon and other parts of the solar system.

The sample, retrieved by the China National Space Administration’s Chang’e-6 lander after a 53-day mission, highlights China’s growing capabilities in space and notches another win in a series of lunar missions that started in 2007 and have so far been executed almost without flaw.

“Chang’e-6 is the first mission in human history to return samples from the far side of the moon,” Long Xiao, a planetary geologist at China University of Geosciences, wrote in an email. “This is a major event for scientists worldwide,” he added, and “a cause for celebration for all humanity.”

Such sentiments and the prospects of international lunar sample exchanges highlighted the hope that China’s robotic missions to the moon and Mars will serve to advance scientific understanding of the solar system. Those possibilities are contrasted by views in Washington and elsewhere that Tuesday’s achievement is the latest milestone in a 21st-century space race with geopolitical overtones.

In February, a privately operated American spacecraft landed on the moon . NASA is also pursuing the Artemis campaign to return Americans to the lunar surface, although its next mission, a flight by astronauts around the moon, has been delayed because of technical issues .

China, too, is looking to expand its presence on the moon, landing more robots there, and eventually human astronauts, in the years to come.

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