Class 9 SST Part 1 Chapter 2 Solutions – Earth's Surface
Looking for accurate and complete ncert class 9 social science chapter 2 solutions for the new CBSE curriculum (2026-27)? You are in the right place! In this guide, we provide step-by-step, direct, and easy-to-understand solutions for all exercise questions from Understanding Society: India and Beyond Class 9 SST Part 1 Chapter 2: Shaping of the Earth's Surface. These answers are crafted specifically to help students write clean, exam-ready answers in their notebooks without extra confusion or lengthy fluff.
Question 1
What are the sources of energy that are required to cause movements associated with the internal forces of the Earth?
The primary source of energy for the Earth's internal forces is the immense heat from the Earth's core. This heat causes the molten material in the mantle to rise and sink, creating convection currents. These currents provide the energy that pushes and pulls the tectonic plates, causing movements like earthquakes, volcanic eruptions, and the formation of mountains.
Question 2
Relate various physiographic divisions you have studied in the earlier grades with various endogenic forces responsible for their origin.
Physiographic divisions (like mountains, plateaus, and plains) are created by endogenic (internal) forces, primarily plate movements:
- Mountains: Formed by the collision of continental plates (e.g., the Himalayas formed by the Indian and Eurasian plates colliding).
- Valleys and Rift Valleys: Formed when tectonic plates move apart (divergent boundaries).
- Ocean Basins: Created by the sinking of oceanic plates or the spreading of the seafloor.
- Volcanoes: Formed when magma rises to the surface at plate boundaries.
Question 3
Why and where do earthquakes occur frequently? Is it possible to predict earthquakes?
- Why they occur: Earthquakes happen when moving tectonic plates suddenly slip, collide, or slide past each other, releasing built-up energy in the form of seismic waves.
- Where they occur: They occur most frequently along plate boundaries, especially around the Pacific Ocean, an area known as the Ring of Fire.
- Prediction: No, it is currently not possible to predict earthquakes accurately. Scientists can only identify earthquake-prone zones, but they cannot predict the exact time, date, or magnitude of an earthquake.
Question 4
"Plate movements are responsible for the distribution of earthquakes and volcanoes." Explain.
This statement is true. Earthquakes and volcanoes are not randomly distributed; they mostly occur along plate boundaries.
- Convergent Boundaries: When plates collide, one sinks below the other. This causes friction, leading to earthquakes, and the sinking plate melts to form magma, causing volcanic eruptions.
- Divergent Boundaries: When plates move apart, magma rises to fill the gap, creating new crust and causing volcanic activity and mild earthquakes.
- Transform Boundaries: When plates slide past each other, they get stuck and then suddenly slip, causing major earthquakes (e.g., San Andreas Fault).
Therefore, the movement of plates is the primary reason for the location of these natural disasters.
Question 5
Draw and label a diagram of a meander and a delta.
(Since this is a drawing question, here is a description to help you draw it):
- Meander: Draw a winding, snake-like curve of a river. On the outer curve (steep bank), show erosion. On the inner curve (gentle bank), show deposition of sand/sediments. Label the River, Steep Bank, and Gentle Bank/Sediment.
- Delta: Draw a river splitting into many smaller channels (distributaries) before meeting the sea. Show triangular-shaped land pieces between the channels. Label the River, Distributaries, and Sea.
Question 6
How are deforestation and erosion associated with each other? Explain.
Deforestation and erosion are directly connected. Trees and plant roots hold the soil tightly in place. When forests are cut down (deforestation), the soil is left loose and exposed. Without roots to hold it, agents like wind and water can easily wash or blow away the fertile topsoil. This process is called erosion. Therefore, deforestation makes the land highly vulnerable to rapid soil erosion.
Question 7
Develop a plan to protect the land in your local area from erosion.
A simple plan to protect local land from erosion includes:
- Planting Trees: Growing more vegetation to hold the soil together with roots.
- Contour Ploughing: Ploughing along the contour lines of a slope to slow down water flow.
- Terracing: Building step-like levels on hilly slopes to prevent soil from washing away.
- Building Check Dams: Constructing small barriers in streams to reduce water speed and allow sediment to settle.
- Proper Drainage: Keeping drains clean to prevent water from collecting and weakening the soil.
Question 8
Which disasters do you think you might experience in your region? Discuss a mitigation plan in your classroom.
(This is a subjective question. Here is a general example based on India)
Disasters: Depending on the region, we might experience earthquakes, floods, landslides, or cyclones. For example, coastal areas face cyclones, while mountainous regions face landslides and avalanches.
Mitigation Plan:
- Create awareness about safety drills (like Drop, Cover, and Hold for earthquakes).
- Keep an emergency kit ready with water, food, medicines, and a flashlight.
- Ensure proper drainage systems to prevent floods.
- Avoid building houses on steep slopes or near riverbanks.
Question 9
Prepare a model of landforms created by underground water.
(This is an activity question). To make a model, you can use clay or papier-mâché to create a cave. Inside, hang cone-like structures from the roof (made of thread or clay) to represent stalactites and build cone-like structures on the floor to represent stalagmites. You can also show a sinkhole on the surface.
Question 10
What precautionary measures will you take if you are staying in an earthquake-prone region?
- Before an earthquake: Secure heavy furniture to walls, keep an emergency kit ready, and identify safe spots in the house (like under strong tables).
- During an earthquake: Drop to the ground, take cover under a sturdy desk, and hold on. Stay away from windows and glass.
- After an earthquake: Stay calm, check for injuries, and do not use elevators. Move to an open area away from buildings.
Question 11
Prepare a map showing landform-associated disasters that happened in the current calendar year.
(This is a project activity). To do this, take a map of India or the world. Use different colors or symbols to mark where disasters occurred this year. For example, mark the Himalayan region for landslides, coastal areas for cyclones, and dry regions for dust storms. Create a legend to explain your symbols.
Question 12
Create a poster showing landforms that are considered to be sacred or important in your region, and add the folk stories associated with them.
(This is a creative activity). You can draw mountains like the Himalayas or rivers like the Ganga. For the folk story, you can mention how the Ganga is considered a sacred river that descended from heaven to earth to cleanse sins, according to Hindu mythology. Or you can depict local hills believed to be the home of local deities.
Question 13
Document a case of a disaster that hit your region in the past, highlighting its effects on various human activities.
(Subjective Example). Case Study: The 2001 Gujarat Earthquake. It caused massive destruction of life and property. It destroyed homes, schools, and hospitals. Trade and business stopped for weeks. Agriculture was affected, and roads were damaged, which disrupted transportation and connectivity.
Question 14
Translate the given poster on landslide into your native language and display it in your home.
(This is a translation activity). The poster in the textbook advises:
- Before: Grow more trees, listen to warnings, keep drains clean, watch for warning signs, and do not build near steep slopes.
- During: Stay calm, do not panic, move away from the landslide path quickly, and inform the nearest Tehsil/District HQ.
- After: Do not touch loose material or electrical wires, check for injured people, and do not drink contaminated water.
Translate these points into your native language and display them.
Question 15
Divide the class into three groups. Each group will work on one project (water, wind, and glacier). The project should highlight the causes, impact on human life and the environment, and mitigation measures.
(This is a group project). Here is a brief outline for the Wind group as an example:
- Causes: Strong winds pick up loose sand and soil, especially in dry regions with little vegetation.
- Impact: It causes soil erosion, reduces agricultural fertility, and creates dust storms that harm human health and visibility.
- Mitigation: Planting trees as windbreaks (shelterbelts), stabilizing sand dunes with vegetation, and practicing contour farming.
Frequently Asked Questions (FAQs)
Based on latest NCERT class 9 book.