All questions of Slow Changes to Earth’s Landscape for Grade 2 Exam

Snow, Hail, Rain are some examples of Precipitation.

In the water Cycle, the Sun heats the water which changes into water vapour and rises up in the sky.

Weathering is the breaking down of rocks and minerals on the surface of the Earth. Water, salts, plants and animals and change in temperature are agents of weathering.

The layers of the soil are called Horizons.

Solar energy is the radiant light and heat that is emitted by the Sun. It is a renewable energy source that is harnessed through various technologies and converted into usable forms of energy such as electricity and heat. Solar energy is a crucial source of power for our planet and plays a significant role in sustaining life on Earth.

Source of Solar energy:

The Sun: The Sun is the primary source of solar energy. It is a giant nuclear reactor that constantly emits vast amounts of heat and light energy. The Sun's energy is produced through a process called nuclear fusion, where hydrogen atoms combine to form helium, releasing tremendous amounts of energy in the process. This energy is then radiated outwards in the form of sunlight.

Solar panels: Solar panels are devices that convert sunlight into electricity. They are made up of photovoltaic (PV) cells, which are usually made from silicon. When sunlight strikes these cells, it excites the electrons in the silicon atoms, creating an electric current. This current can then be used to power electrical devices or stored in batteries for later use.

Solar thermal systems: Solar thermal systems use the heat energy from sunlight to generate heat or produce hot water. These systems typically consist of solar collectors, which absorb the heat from the Sun, and a heat transfer medium such as water or air. The heated medium can then be used for various purposes, including heating buildings, heating water, or generating steam for power generation.

Importance of Solar energy:

- Renewable: Solar energy is a renewable resource, meaning it will never run out as long as the Sun continues to exist. This makes it a sustainable and environmentally friendly source of energy.

- Clean and emissions-free: Solar energy production does not produce greenhouse gas emissions or air pollutants like traditional fossil fuels. This helps to reduce air pollution and combat climate change.

- Cost-effective: The cost of solar energy has significantly decreased over the years, making it more affordable and accessible to a wider range of people. It can also help reduce electricity bills in the long run.

- Versatile: Solar energy can be harnessed and utilized in various ways, including generating electricity, heating water, powering vehicles, and even providing lighting in remote areas.

- Energy independence: Solar energy allows individuals and communities to become more self-sufficient and less reliant on external energy sources. This can enhance energy security and reduce dependence on imported fossil fuels.

Overall, solar energy is a vital and abundant source of power that has numerous benefits for both the environment and society. Its importance and utilization are expected to continue growing as we strive towards a more sustainable and clean energy future.

The Animals which live both on land and water are called Amphibians. e.g. Frog.

Explanation:

Statement 1: Lichen and plant roots break the rocks into pieces.
This statement is true. Lichen is a combination of algae and fungi that grow on rocks. The fungi in lichen produce acids that slowly break down the rocks into smaller pieces. Plant roots, especially those of larger plants, can also break rocks as they grow and expand. This process is known as physical weathering.

Statement 2: Topsoil is the layer of hard rocks.
This statement is false. Topsoil is not the layer of hard rocks. Topsoil is the uppermost layer of soil, typically a few inches to several inches thick, that contains a high concentration of organic matter. It is rich in nutrients and is where most plants grow. Below the topsoil, there are layers of subsoil and bedrock.

Conclusion:
From the above analysis, we can conclude that statement 1 is true and statement 2 is false. Therefore, the correct answer is option 'A' - Statements 1 is true and 2 is false.

The correct answer is option 'A' (i) and (ii) only.

(i) The sun provides green plants with light energy to make food:
- Plants use a process called photosynthesis to make their own food.
- They need sunlight to carry out this process.
- Sunlight provides the energy needed for photosynthesis.
- Without sunlight, plants would not be able to produce food and survive.
- Plants are the primary producers in the food chain, meaning they are the foundation of the entire ecosystem.
- They provide food for animals, including humans, and release oxygen as a byproduct of photosynthesis, which is essential for all living organisms.

(ii) The sun provides heat to enable living things to survive on Earth:
- The sun's energy warms the Earth's surface, creating a suitable environment for life.
- The heat from the sun helps maintain the Earth's temperature within a range that allows living organisms to survive.
- It provides warmth for animals and humans to stay active and maintain their body temperature.
- Sunlight also plays a crucial role in regulating the Earth's climate and weather patterns.

(iii) The statement "It rotates around the Earth to give us seasons" is incorrect:
- The sun does not rotate around the Earth; instead, the Earth orbits around the sun.
- The changing seasons on Earth are caused by the tilt of the Earth's axis as it orbits the sun.
- This tilt causes different parts of the Earth to be exposed to varying amounts of sunlight throughout the year, leading to the different seasons.

In conclusion, the sun is important to the Earth because it provides green plants with light energy for photosynthesis, allowing them to produce food and release oxygen. Additionally, the sun's heat enables living things to survive on Earth by creating a suitable environment and maintaining the Earth's temperature.

Explanation:

Mrs. Sharma reusing water that was used to wash vegetables to water her plants is an example of water conservation. Water conservation refers to the practice of using water wisely and efficiently in order to preserve and protect this precious natural resource.

Here is a detailed explanation of why reusing water for plants is a form of water conservation:

1. Water Reuse:
- Reusing water means using it again for a different purpose instead of letting it go to waste.
- In this case, Mrs. Sharma is reusing the water that was used to wash vegetables instead of directly discarding it.

2. Conservation:
- Conservation refers to the careful use, management, and protection of natural resources.
- By reusing water for her plants, Mrs. Sharma is conserving water by not letting it go to waste.

3. Importance of Water Conservation:
- Water is a finite resource, meaning there is a limited amount of it on Earth.
- It is essential for all living beings and is used for various purposes such as drinking, cooking, agriculture, and industrial processes.
- However, the demand for water is increasing due to population growth, urbanization, and industrialization.
- Therefore, it is crucial to conserve water to ensure its availability for future generations and to maintain ecological balance.

4. Reusing Water for Plants:
- Reusing water that was used to wash vegetables for watering plants is an excellent example of water conservation.
- Instead of letting the water flow down the drain, Mrs. Sharma is utilizing it to fulfill another important purpose.
- The water used for washing vegetables may contain nutrients and organic matter that can benefit the plants when used for watering.
- By reusing this water, Mrs. Sharma is reducing her water consumption and minimizing wastage.

5. Other Water Conservation Practices:
- Apart from reusing water for plants, there are several other ways to conserve water:
- Fixing leaky faucets and pipes to prevent water wastage.
- Taking shorter showers and turning off the tap while brushing teeth.
- Collecting rainwater for outdoor watering.
- Using water-efficient appliances and fixtures.
- Practicing responsible irrigation techniques in agriculture.

Conclusion:

In conclusion, Mrs. Sharma's act of reusing water used for washing vegetables to water her plants is an example of water conservation. It is important for everyone to adopt such practices to preserve and protect this valuable resource for future generations.

Dew is a natural form of water, formed as water vapour condenses that appears on thin exposed objects in the morning or evening.

Explanation:

Introduction:
Water is one of the essential elements to sustain life on earth. It is present in different forms like oceans, rivers, lakes, glaciers, etc. There are different sources of water, and based on their origin, they are classified as natural and man-made sources.

Natural sources of water:
Natural sources of water are the ones that are present in nature without any human intervention. They are as follows:

1. Groundwater: It is the water that is present beneath the earth's surface and can be accessed through wells and tube wells. It is a renewable source of water, and the recharge of groundwater depends on the rainfall and percolation of water through the soil.

2. Surface water: It is the water that is present on the surface of the earth in the form of rivers, lakes, and oceans. Surface water is the primary source of water for human consumption, agriculture, and industries.

3. Rainwater: It is the precipitation that falls on the earth's surface in the form of rain, snow, sleet, or hail. It is a natural source of freshwater and is collected through different methods like roof rainwater harvesting, surface runoff harvesting, etc.

Man-made sources of water:
Man-made sources of water are the ones that are created by humans for their use. They are as follows:

1. Tap water: It is the water that is supplied to homes, offices, and industries through a network of pipes. Tap water is treated and disinfected to make it safe for human consumption.

Odd one out:
The odd one out among the given options is option 'B' (Tap water) because it is a man-made source of water and not a natural source of water like the other options. Tap water is created by humans, whereas the other options are present in nature without any human intervention.

Answer:

The correct option is b) FTTT.

Explanation:

(i) Plants do not require water for photosynthesis. (False)
- This statement is false. Plants require water for photosynthesis. Photosynthesis is the process by which plants convert sunlight, carbon dioxide, and water into glucose (a type of sugar) and oxygen. Water is one of the essential components needed for this process.

(ii) About 50% of Earth is covered with water. (True)
- This statement is true. Approximately 71% of the Earth's surface is covered with water. This includes oceans, seas, lakes, rivers, and other water bodies.

(iii) Water should be reused, saved and conserved. (True)
- This statement is true. Water is a precious resource, and it is important to reuse, save, and conserve it. This is because water scarcity is a growing issue in many parts of the world. By reusing water, practicing water-saving habits, and conserving water, we can ensure its availability for future generations.

(iv) Animals that live in water are called aquatic animals. (True)
- This statement is true. Animals that live in water, such as fish, dolphins, and turtles, are called aquatic animals. They have adapted to their aquatic environment and rely on water for survival.

In conclusion, the correct option is b) FTTT, as statements (ii), (iii), and (iv) are true, while statement (i) is false.

Soil contains both water and air for growth of plants.

The boiling point of water is 100^o C.

Birds do not take part in soil formation.

The correct answer is option 'D', bedrock. Let's understand why bedrock is considered the hardest layer of the soil.

Soil is made up of different layers, also known as soil horizons, that vary in composition, color, and texture. These layers are formed over long periods of time through the weathering of rocks, minerals, and organic matter. The layers of soil are typically categorized into four main horizons: topsoil, subsoil, parent material, and bedrock.

1. Topsoil:
- The topsoil is the uppermost layer of soil and is the most fertile layer for plant growth.
- It is rich in organic matter, nutrients, and microorganisms, which support the growth of plants and provide a favorable environment for their roots.
- The topsoil is relatively loose and easy to dig or cultivate.

2. Subsoil:
- Below the topsoil, there is a layer called subsoil.
- The subsoil is generally less fertile compared to the topsoil and contains fewer organic materials.
- It mainly consists of weathered rocks, clay, and minerals that have leached down from the topsoil.
- The subsoil is usually denser and more compact than the topsoil.

3. Parent Material:
- The parent material is the layer beneath the subsoil and is composed of partially weathered rocks and minerals.
- It is the source material from which the soil is formed.
- The parent material undergoes weathering and other geological processes over a long period to form the different layers of soil.

4. Bedrock:
- The bedrock is the bottom-most layer of the soil profile.
- It is the solid, unweathered rock that lies beneath the other soil layers.
- Bedrock is extremely hard and compact, composed of solid rock that has not undergone significant weathering or erosion.
- It provides a stable foundation for the soil layers above it.

Why is bedrock considered the hardest layer?
- Bedrock is the hardest layer of soil because it is composed of solid, unweathered rock.
- Unlike the other layers of soil that have undergone weathering and decomposition, bedrock remains solid and resistant to erosion.
- It requires heavy machinery or drilling equipment to break through the bedrock for construction or excavation purposes.

In conclusion, while each layer of soil has its own characteristics, bedrock is considered the hardest layer because it is composed of solid, unweathered rock that provides a stable foundation for the soil layers above it.

Introduction:
The balance of gases in the air refers to the natural composition of gases present in the Earth's atmosphere. This balance is essential for maintaining a healthy and stable environment. However, certain human activities can disrupt this balance and lead to environmental issues such as air pollution and climate change.

Explanation:
- Cutting down trees and forests: The cutting down of trees and forests has a significant impact on the balance of gases in the air. Trees play a crucial role in the process of photosynthesis, where they absorb carbon dioxide (a greenhouse gas) and release oxygen. By cutting down trees, the amount of carbon dioxide in the atmosphere increases, disturbing the balance of gases.

- Releasing polluting gases into the air: The release of polluting gases, such as carbon dioxide, sulfur dioxide, and nitrogen oxides, into the air has a detrimental effect on the balance of gases. These gases are often emitted from industrial processes, power plants, and vehicles. They contribute to air pollution and can lead to health problems and climate change.

- Releasing smoke from the vehicles: The release of smoke from vehicles is another activity that disturbs the balance of gases in the air. Vehicle emissions contain pollutants such as carbon monoxide, nitrogen oxides, and particulate matter. These pollutants can have adverse effects on air quality and human health.

- Growing trees: Growing trees, on the other hand, does not disturb the balance of gases in the air. As mentioned earlier, trees absorb carbon dioxide during photosynthesis and release oxygen. By planting and growing trees, we can help offset the carbon dioxide emissions and restore the balance of gases in the air. Trees also provide shade, habitat for wildlife, and contribute to the overall well-being of the environment.

Conclusion:
In conclusion, cutting down trees and forests, releasing polluting gases into the air, and releasing smoke from vehicles all disturb the balance of gases in the air. However, growing trees helps to restore this balance by absorbing carbon dioxide and releasing oxygen. Therefore, the correct answer is option 'C' - growing trees.

Loam is a type of soil that is considered to be the most ideal for plant growth. It is a mixture of sand, silt, and clay in relatively equal proportions. Each component plays a vital role in the overall characteristics and fertility of the soil.

Sand:
- Sand particles are the largest component found in loam soil.
- They are gritty and have a coarse texture.
- Sand particles allow for good drainage and prevent the soil from becoming waterlogged.
- They also provide aeration to the roots, allowing them to access oxygen.
- However, sand has a low water-holding capacity, which means it can quickly dry out.

Silt:
- Silt particles are smaller than sand particles but larger than clay particles.
- They have a smooth texture and feel like flour when dry.
- Silt helps to improve the water-holding capacity of the soil.
- It also aids in nutrient retention and provides a fertile environment for plant roots.
- However, silt can easily become compacted and lose its ability to drain properly.

Clay:
- Clay particles are the smallest component found in loam soil.
- They have a sticky and smooth texture when wet and become hard and compacted when dry.
- Clay has high water-holding capacity, which can lead to poor drainage if present in large amounts.
- It also has high nutrient-holding capacity, making it a valuable component for plant growth.
- However, clay soils can become easily compacted and hard to work with.

Combination of Sand, Silt, and Clay:
- The combination of sand, silt, and clay in loam soil creates an ideal balance of drainage, water retention, and nutrient availability.
- The sand provides good drainage, the silt improves water-holding capacity, and the clay enhances nutrient retention.
- This balanced composition allows for optimal root growth, nutrient uptake, and plant development.
- Loam soil is easily workable and has good structure, making it ideal for gardening and agricultural purposes.
- It is often referred to as "the gardener's friend" due to its fertility and versatility.

In conclusion, loam soil is a mixture of sand, silt, and clay in equal proportions. This combination provides optimal conditions for plant growth, including good drainage, water retention, and nutrient availability. Loam soil is highly fertile and widely used in gardening and agriculture.

Humidity is the concentration of water vapour present in air.

Introduction:
Weather refers to the conditions of the atmosphere at a particular place and time. It includes elements such as temperature, precipitation, wind, humidity, and atmospheric pressure. All these factors contribute to the overall weather patterns and conditions experienced in a specific area.

Explanation:
The correct answer to the question is option 'B' - All of these. This means that all the given options - temperature, rain, and wind - affect the weather.

Temperature:
Temperature is a significant factor that influences the weather. It refers to the degree of hotness or coldness of the air. Different temperature ranges lead to various weather conditions. For example, high temperatures contribute to hot and dry weather, while low temperatures result in cold and snowy weather.

Rain:
Rainfall is another essential element that affects the weather. It refers to the precipitation of water droplets from the atmosphere. Rainfall patterns determine whether an area experiences wet or dry conditions. Areas with high rainfall are generally characterized by a humid climate, while areas with low rainfall are typically arid or semi-arid.

Wind:
Wind is the movement of air in the atmosphere. It plays a crucial role in determining weather conditions. Wind patterns influence factors such as temperature, humidity, and precipitation. For example, wind blowing from a cold region can lower the temperature in a specific area, while wind blowing from a warm region can increase the temperature.

Conclusion:
In conclusion, all the given options - temperature, rain, and wind - affect the weather. Temperature determines the hotness or coldness of the air, rain determines the precipitation patterns, and wind influences various weather factors. Understanding the relationship between these elements helps meteorologists predict and analyze weather conditions accurately.

In summer, days are longer than the nights.

Winters occur during December - January

Milk, Oil and Water are liquids, they attain the shape of the container. Pencil is solid, it has a definite shape.

Water has no odour and taste. Water changes into water vapour due to evaporation.

To buy a Raincoat,Madan can wear a raincoat while driving a motorbike to get rid of wetness during rain.

Weather becomes pleasant and comfortable during spring because of Breeze. Clothes dry fastest in the summer season.