NCERT Class 6 Science Chapter 11 Nature’s Treasures Important Extra Questions and Answers

Very Short Answer Type Questions

Question 1.
What are the two most widely used fuels for vehicles?
Answer:
Petrol and diesel

Question 2.
Which fossil fuels are obtained from petroleum?
Answer:
Petrol, diesel and kerosene

 

Question 3.
What is the primary use of natural gas?
Answer:
Cooking and generating electricity

Question 4.
Why is compressed natural gas (CNG) considered a cleaner fuel compared to petrol or diesel?
Answer:
CNG is considered a cleaner fuel because it produces fewer pollutants and greenhouse gases when burned.

Question 5.
What is the main use of coal?
Answer:
The production of electricity

Short Answer Type Questions

Question 1.
What is rainwater harvesting, and how is it implemented in buildings?
Answer:
Rainwater harvesting is the practice of collecting and storing rainwater for later use. In buildings, this is often done by setting up systems to capture rainwater from roofs or other surfaces and directing it into storage tanks. This stored water can be used for various purposes such as irrigation, flushing toilets, or even drinking, depending on the level of treatment it receives.

Question 2.
Describe the traditional water harvesting system used in Rajasthan and Gujarat.
Answer:
In Rajasthan and Gujarat, traditional water harvesting systems include stepwells (known as Bawadi in Rajasthan and Vav in Gujarat). These step-wells are deep, vertical wells with steps leading down to the water. They collect rainwater as well as water that seeps from nearby lakes, ponds and rivers. The walls of the step-wells are lined with stones that allow water to seep through, ensuring a steady water supply even during dry periods.

 

Question 3.
How does the Sun contribute to the drying process of food items, such as chillies or mangoes?
Answer:
The Sun contributes to the drying process by providing heat that promotes the evaporation of moisture from food items. For instance, when chillies or mangoes are exposed to the Sun, the heat causes the moisture in these items to evaporate, thus drying them. This method helps preserve food for future use when fresh produce is not available.

Long Answer Type Questions

Question 1.
Explain the difference between renewable and nonrenewable natural resources with examples.
Answer:
Renewable resources are natural resources that can be replenished or restored through natural processes within a relatively short period of time. Examples include:

• Air: Continuously refreshed through natural processes like photosynthesis and the water cycle.
• Water: Renewed through the water cycle, although it may néed conservation to prevent depletion.
• Forests: Can regenerate through natural growth and seed dispersal, though this process can be slow.

On the other hand, non-renewable resources are those that take millions of years to form and are found in limited quantities. They cannot be replenished within a human lifespan once exhausted.

Examples include:

• Coal: Formed over millions of years from ancient plant material, used primarily for electricity generation.
• Petroleum: This includes oil and natural gas, which are formed from ancient marine organisms and are used for fuel and various other products.
• Minerals and Rocks: These resources are extracted for construction and manufacturing but cannot be replenished quickly.

 

Question 2.
Discuss the importance of conserving natural resources and suggest practical ways to conserve both renewable and non-renewable resources.
Answer:
Conserving natural resources is crucial for maintaining ecological balance, ensuring sustainable development and preserving the environment for future generations. Overuse or depletion of resources can lead to environmental degradation, loss of biodiversity and scarcity of essential resources.

Practical ways to conserve renewable resources:

• Water conservation: Use water-saving fixtures, fix leaks and adopt practices like rainwater harvesting.
• Forest conservation: Support afforestation projects, avoid deforestation and use resources like paper and wood sustainably.
• Energy conservation: Utilise renewable energy sources like solar panels and wind turbines and reduce energy consumption through efficient appliances.

Practical ways to conserve non-renewable resources:

• Reduce fossil fuel use: Opt for alternative energy sources such as electric vehicles and public transport instead of personal cars.
• Recycling and Reuse: Recycle materials like metals, plastics and glass to reduce the need for new raw materials.
• Sustainable practices: Encourage industries to adopt sustainable practices and technologies that minimise the extraction and use of non-renewable resources.

Air Class 6 Extra Questions

Question 1.
What is wind?
Answer:
Wind is the movement of air caused by the uneven heating of the earth by the sun.

Question 2.
Describe the composition of air.
Answer:
Air contains mostly nitrogen (78%) and oxygen (21%). The remaining 1% (by volume) is shared by argon (0.34%), carbon dioxide (0.33%), other noble gases, oxides of nitrogen and sulphur etc., in the decreasing order

The relative proportion of main gases present in air

Question 3.
What will happen if the amount of oxygen is increased in the air?
Answer:
Air will become more combustible and many substances may undergo fast oxidation.

Question 4.
Name the substances which are present in traces in air. What are these together called?
Answer:
Xenon (Xe), Krypton (Kr), Neon (Ne) and Helium (He) are present in traces in the air. These together form 0.02% of air and are called inert gases.

Question 5.
How will you prove that air is a mixture of several gases and not a compound?
Answer:
The following points show that air is a mixture :

1. 1. The composition of air varies slightly from place to place.
   2. Different components of air are separable by physical processes.
   3. Different components of air exhibit their characteristics, for example, O₂ in air supports combustion, CO₂ in air turns lime water milky.

 

Question 6.
What are the properties of air?
Answer:

1. Air occupies space.
2. Air is present everywhere around us.
3. Air has no colour and one can see through it.
4. It is transparent.

Question 7.
What is atmosphere?
Answer:
Our earth is surrounded by a thin layer of air. This layer is called atmosphere. It extends up to many kilometres above the surface of the earth.

Question 8.
Why is atmosphere called the place where exchange of gases in nature occurs?
Answer:
We know that various gases are found in air. Now some organisms live on land, some in water and some deep under the soil. But all need oxygen to respire. The terrestrial organisms take oxygen from the atmosphere. You know that during respiration by living beings and burning of materials, carbon dioxide is produced along with some other gases. Also CO² is used by the plants in the process of photosynthesis in which oxygen is released. All gases go into the atmosphere. Thus, it is a place in nature for gaseous exchange.

Question 9.
The mountaineers carry oxygen cylinder with them while climbing high mountains. Why?
Answer:
The availability of air decreases gradually as we go up in the atmosphere.

Question 10.
Explain the following observations very briefly.
(a) A firki does not rotate in a closed area.
(b) The arrow of weather cock points towards a particular direction at a particular moment.
(c) An empty glass in fact is not empty.
(d) Breathing through mouth may harm you.
Answer:
(a) Lack of air movement
(b) Shows the latest direction of the wind.
(c) Even the so called empty glass is not in fact empty. It is filled with air.
(d) You may inhale dust if present in air which may prove harmful.

Question 11.
Name the gases present in air. Which one of them is most abundant?
Answer:
N₂, O₂, Ar (argon), CO₂, water vapour, neon (Ne), helium (He), krypton (Kr), xenon (Xe) are present in air. Nitrogen is most abundant.

Water Class 6 Extra Questions

Question 1.
Write the sources of water on the earth.
Answer:
Oceans, Rivers, Springs, Tubewells, Rain water, etc.

Question 2.
In which forms, water exists on the earth?
Answer:
Water exists on the earth in all three physical forms : Ice, water and water vapour.

 

Question 3.
Mention two main functions of water for living organisms.
Answer:

1. Water is essential for the germination of seeds, growth of plants and in photosynthesis.
2. Water is used for the transportation of people and goods

Question 4.
Why is ocean water not suitable for domestic use?
Answer:
Sea and ocean water contains large amounts of various salts. It is due to these salts the ocean water is salty and cannot be used for drinking, washing and for irrigation purposes.

Question 5.
What is meant by conservation of water? Suggest three methods to conserve water.
Answer:
Careful and economical use of water and avoiding its wastage is called conservation of water:

1. Use only the limited quantity of water.
2. To conserve water, we should plant more and more trees.
3. By collecting rainwater in tanks, ponds or by constructing check dams.

 

Question 6.
What is rainwater harvesting? Describe the method of rainwater harvesting.
Answer:
Rainwater harvesting is the collection of rainwater and storing for future use. In this system rainwater in collected from the rooftops by means of pipes into storage tank for later use. Recycling water and water harvesting also help in saving water.

Methods of Rainwater Harvesting:

1. Rooftop rainwater harvesting. In this system, the rainwater from the rooftop is collected in a storage tank, through pipes.
2. Another method, a big pit is dug near house for collecting rainwater. This pit is filled with different layers of bricks, coarse gravels and sand or granite pieces.

Energy from The Sun Class 6 Extra Questions

Question 1.
Name the main source of energy on Earth.
Answer:
Sun

Question 2.
What is photosynthesis?
Answer:
“The process, by which green plants make their own food from carbon dioxide (C02) and water (H20) in the presence of sunlight and green pigment (chlorophyll) is called Photosynthesis.”

Question 3.
What is the ultimate source of energy for all living organisms?
Answer:
Sun is the ultimate source of energy for all living organisms.

Forests Class 6 Extra Questions

Question 1.
What are forests?
Answer:
Forests are large areas with dense growth of various types of plants (herbs, shrubs and trees). Forests are a natural home for many wild animals, including birds and insects. Forests provide food and shelter to them.

Question 2.
Why should we worry about the conditions and issues related to forests far from us?
Answer:
We should worry about the conditions and issues related to forests even far from us because forests play an important role for the sustenance of life on earth. The following points illustrate the importance of forests for us :

1. Forests help in maintaining the ratio of oxygen and carbon dioxide in air.
2. Forests provide habitat to a wide variety of plants and animals.
3. Forests provide firewood, timber, medicines, fruits, rubber, gum, resins, honey, bee-wax, paper and many other products.
4. Forests reduce the speed of flowing water and help in controlling floods.

Question 3.
Explain how animals dwelling in the forest help it grow and regenerate.
Answer:
We can see a bunch of seedlings sprouting in a decaying heap of animal droppings especially in rainy seasons. These seedlings are the herbs and shrubs. The animals also disperse the seeds of certain plants and help the forest to grow and regenerate. The decaying animal dung also provides nutrients to the seedlings to grow.

Question 4.
Explain how forests prevent floods.
Answer:
Raindrops in a forest do not hit the ground directly. The uppermost layer of the forest canopy intercepts the raindrops, and most of the water comes down up to soil through the branches and the stems of the trees. From the leaves it drops slowly over the branches of the shrubs and herbs. Also forest trees have extensive deep roots that absorb and store rain water. Thus forests act as a natural absorber of rainwater and allows it to seep and therefore help in controlling floods.

Question 5.
Explain Van-Mahotsav.
Answer:
Van-Mahotsav is a week-long event celebrated across the country during the month of July. It is a forest festival during which new plants and trees are planted and awareness about respecting forests is raised.

 

Question 6.
Explain the role of forest in maintaining the balance between oxygen and carbon dioxide in the atmosphere.
Answer:
Plants release oxygen as a by product during the process of photosynthesis. This oxygen is inhaled by animals for respiration. This respiration process releases carbon dioxide which is used again by plants during photosynthesis. In this way, use and consumption of oxygen and carbon dioxide goes on. Thus, they maintain the balance of oxygen and carbon dioxide in the atmosphere.

Question 7.
How does the forest floor look like?
Answer:
The forest floor looks dark- coloured and is covered with a layer of dead and decaying leaves, fruits, seeds, twigs and small herbs. The decaying matter is moist and warm. Walking over the dead leaf layer on the forest floor is like walking over a spongy carpet.

Question 8.
What is the importance of dense bushes and tall grasses for animals living in the forest?
Answer:
The dense bushes and the tall grasses provide the food and shelter to the animals. They also protect them from carnivores that live in the forest.

Soil, Rocks and Minerals Class 6 Extra Questions

Question 1.
What is soil?
Answer:
Soil is made up of small pieces of broken rock and decaying plants.

Question 2.
What are crumbs?
Answer:
The ploughed field may have big pieces of soil called crumbs.

 

Question 3.
Write some useful tools used in ploughing and levelling.
Answer:
Wooden plough, iron plough, and soil plank.

Question 4.
What is rock?
Answer:
Any natural mass of mineral matter that makes up the earth’s crust is called a rock.

Fossil Fuels Class 6 Extra Questions

Question 1.
What is the full form of LPG?
Answer:
Liquefied petroleum gas.

Question 2.
Name the petroleum product which is commonly used for electric generators.
Answer:
Diesel is used as a fuel for electric generators.

Question 3.
Name the fuel which is used in jet aircraft engines.
Answer:
Kerosene is used as fuel in jet aircraft engines.

Question 4.
Name the petroleum product used to drive heavy vehicles.
Answer:
Diesel is used as a fuel for heavy motor vehicles and electric generators.

Question 5.
What is the full form of CNG?
Answer:
Compressed Natural Gas.

Natural Resources : Renewable and Non-Renewable Class 6 Extra Questions

Question 1.
What is a non-renewable Resource?
Answer:
Natural resources that are limited in quantity are referred to as non¬renewable resources. These resources cannot be supplied or regenerated in a short duration of time. These resources cannot be reused.

Question 2.
Which are the most commonly used renewable energy sources?
Answer:
Solar energy, wind energy, hydropower, tidal energy, and geothermal energy are some of the important sources of renewable energy.

 

Question 3.
What is meant by a renewable energy source?
Answer:
A renewable energy source is an energy source that inflicts no adverse effects on nature. They are abundant in nature and are extremely sustainable. These sources are replenished naturally and are predominantly eco-friendly.

Question 4.
What are the two types of energy consumed by human civilisation?
Answer:
Energy sources can be divided into renewable energy sources and non¬renewable energy sources.

Resources we use Class 6 Extra Questions

Question 1.
What is resource?
Answer:
Resource is a source of supply that is kept in reserve in order to be converted into something more valuable – and helpful.

Question 2.
What are the two types of natural resources?
Answer:
Renewable and non-renewable natural resources are the two types of natural resources.

 

Question 3.
List out four resources you use in your home and four you used in your classroom
Answer:
The list of four resources which we use in our home are:

1. Television
2. Water
3. Furniture
4. Utensils

The list of four resources that we use in our classroom are:

1. Book
2. Chalk
3. Blackboard
4. Water