11. Nature’s Treasures · Class 6 Science
Practise 100 short and long answer questions on Textbook-based subjective questions from 11. Nature’s Treasures. Try writing your own answer first, then tap the question to compare it with the model answer and read the explanation behind it.
School vacations are always fun for Bhoomi and Surya.
This vacation, they visit their Ajji (grandmother).
The air in the village is fresh and cooler than in the city.
They can see beautiful hills, streams, and many interesting plants, animals and birds around them.
Ajji says, “Children, do you know that this place has several treasures of nature that enrich our lives? The pure air is refreshing and the soil is so fertile that it supports a variety of living beings.
Moreover, this place gets plenty of sunlight which is useful in many ways.
Different varieties of trees provide food and shelter to animals including various birds and insects. Can you think of more such treasures of nature?”
Bhoomi replies, “Ajji, we use water for drinking and growing vegetables.” Ajji says, “Yes.
We need these treasures for our survival and for making our lives more comfortable. Without these treasures of nature, any form of life on Earth is not possible.” We all are a part of nature. Ajji explains the importance of air around us and how it is essential for our survival.
11.1 Air One morning, Bhoomi and Surya see Ajji performing some breathing exercises.
11.1 Air One morning, Bhoomi and Surya see Ajji performing some breathing exercises. She says, “I am taking deep breaths in, and letting them out. This helps in getting more fresh air in the lungs to stay healthy.” Bhoomi and Surya sit with Ajji and start taking deep breaths.
Let us also perform a breathing exercise.
Let us also perform a breathing exercise.
Breathing exercise Activity 11.1: Let us experience Take a deep breath in, and then breathe out slowly. Take a deeper breath in again. Hold your breath for as long as you can and then breathe out slowly. How long can you hold your breath?
The air which we breathe in has oxygen.
Our body needs Caution oxygen to perform its functions.
Thus, that you start feeling we need oxygen for our survival. Similarly, uncomfortable. most of the living beings also need oxygen for their survival.
We can survive without food or water for a few days, but we cannot survive without oxygen for Do you even a few minutes. know?
The air which surrounds the Earth is a mixture of gases. Can you name some gases which are present in the air?
Air contains nitrogen, oxygen, argon, carbon dioxide and other gases in small quantities.
11.1 gives the composition of air in percentage. Out of 100 squares, 78 are occupied by nitrogen, 21 are occupied by oxygen, and 1 by argon, carbon dioxide and other gases. Percentage is the number of parts in 100.
You notice the presence of air when the leaves of a tree rustle, the clothes hanging on a clothes line sway, or the pages Nature’s Treasures
You notice the presence of air when the leaves of a tree rustle, the clothes hanging on a clothes line sway, or the pages Nature’s Treasures of an open book begin to flutter once a fan is switched on. Sometimes it blows fast, for example, during a storm, and sometimes it blows gently as a breeze.
You must have played with a firki (paper pinwheel) many times.
You must have played with a firki (paper pinwheel) many times.
Let us make a firki by performing Activity 11.2.
Now, you can hold the firki in your hand and run.
When you move it a little back and forth, the firki rotates.
The working of a windmill is similar to that of a firki. Windmills can be used to run flour mills, to pull up water from a well, or to generate electricity.
In India, there are many windmill farms.
A windmill farm is an area that has a large number of windmills which use the energy of Fig 11.3: A windmill farm the wind to generate electricity (Fig. Muppandal Wind Farm in Tamil Nadu, Jaisalmer Wind Park in Rajasthan and Brahmanvel Wind Farm in Maharashtra are some of the leading windmill farms in our country.
Find out more More to other windmill farms in our country. know!
We have learnt that air is very important for us. Water too is essential and precious for us. How do you feel when you cannot get water to drink, especially when you are thirsty?
11.2 Water Bhoomi and Surya help Ajji in filling the troughs of water for the cows.
11.2 Water Bhoomi and Surya help Ajji in filling the troughs of water for the cows. They also help her in watering plants such as vegetables and medicinal herbs in the garden. Ajji teaches them how to water the plants so that every drop is used and none of it goes waste.
Can you think of some more uses of water in your daily life?
Can you think of some more uses of water in your daily life?
Write down your responses in the blank bubble.
It is also used for growing crops and for industrial purposes.
Make a list of the different sources of water.
Most of the water is found in oceans and seas. However, this water is saline or salty.
This saline water is not fit for domestic, agricultural and industrial use.
For all these activities, we need freshwater, which is present in the form of ice sheets or snow, rivers or lakes on the surface of the Earth, and underground. and snow, or underground water is difficult to access.
A very small fraction of the freshwater present in ponds, rivers, lakes and wells is easily accessible.
Water is precious, that is why Ajji guides them to use it with care. Do you feel that water is being used efficiently in our daily activities? Have you observed water being wasted in your daily activities?
Let us find out activities where water is wasted and how this wastage can be reduced.
Let us find out activities where water is wasted and how this wastage can be reduced. What conclusion can you draw from the information you gathered in the table? What can you and your family do to reduce this wastage of water?
There are many ways to reduce wastage of water.
There are many ways to reduce wastage of water.
For example, turning off taps when not in use and fixing water leakages.
Our country is blessed with numerous rivers, streams and lakes.
Have you ever noticed plastic bags and wrappers floating on the surface of water?
Waste from homes and industries pollute our water sources when it is dumped into them. Identify other human activities that lead to water pollution.
Discuss with your friends in the class what you can do to reduce water pollution.
Polluted water is not fit for consumption by living beings. As freshwater sources are limited, there is a shortage of water in many parts of India.
At some places, people have to walk long distances to fetch drinking water.
Everyone does not have the same kind of access to water. It is important for us to conserve water and use it judiciously. We must also prevent it from being polluted so that water remains fit for consumption by all living beings.
Water harvesting is one of the methods for conserving water.
Water harvesting is one of the methods for conserving water. In many buildings, rainwater is collected and stored in large quantities for later use. This is called rainwater harvesting (Fig.
Do you know that rainwater is also harvested in many homes, residential societies or schools?
Do you know that rainwater is also harvested in many homes, residential societies or schools?
11.4 (a): Rainwater harvesting commonly known as Bawadi in Rajasthan and Vav in Gujarat are built for water harvesting as a response to the scarcity of water in these regions.
They store not only rainwater but also water seeping from nearby lakes, ponds and rivers.
the trenches (long deep holes dug in the ground) are lined with blocks of stones that allow seepage of water.
11.4 (b): Bawadi (Toorji ka Jhalra, with your teachers and parents to Jodhpur in Rajasthan) learn more about it. World Water Day is observed on 22nd March every year.
In the chapter ‘A Journey through States of Water’, we have learnt about the water cycle, where the Sun plays an important role in the evaporation of water.
Have you ever observed your mother or grandmother cut raw mangoes and expose them to the hot sun for several days to dry? Let us explore more about energy from the Sun.
11.3 Energy from the Sun On a sunny day, Bhoomi and Surya are helping Ajji dry chillies in the Sun.
Ajji says, “We use the heat from the Sun to dry it. We can use dried chillies when fresh ones are not available. Do you know that the Sun is the main source of energy on Earth?
All plants and animals are dependent on it.” We use heat and light from the Sun for various purposes.
All plants and animals are dependent on it.” We use heat and light from the Sun for various purposes. What are some of the activities for which we need heat and light? Bhoomi draws some pictures to show the uses of heat and light from the Sun.
Draw the pictures and write their descriptions in the space provided.
Draw the pictures and write their descriptions in the space provided.
One afternoon, Bhoomi and Surya pass by the field near Ajji’s house, where they see a cow grazing the grass.
Read the conversation carefully and answer.
It is this cow grazing the is getting grass and energy from getting energy the Sun. from it.
So, does not mean that it the main source of energy is getting energy from is the Sun. This way the the Sun. cow gets energy from the Sun.
The Sun also provides all the living beings on Earth with heat and light.
In many households in India, water is offered to the Sun early Do you in the morning as an expression of gratitude to the Sun. know? rooftops, on top of street lights or on traffic signals?
capture the Sun’s energy and produce electricity.
Energy from the Sun can also be directly used for cooking in a solar cooker or for heating water in a solar water heater. One cannot imagine life on What will happen if the Sun Earth without the Sun. The Sun is is not visible for a few days? the main source of energy on the 1. We may have to depend Earth.
Plants get energy from the on artificial lighting Sun and produce food.
Plants get energy from the on artificial lighting Sun and produce food. Animals eat during day time also. plants and grow. This cycle on Earth is possible due to the Sun.
So, we all are dependent on the Sun as the main source of energy.
So, we all are dependent on the Sun as the main source of energy.
Where do we find a large variety of plants or animals?
They find a variety of herbs, shrubs and trees in the forest.
Ajji explains, “Forests are large areas with dense growth of various types of plants.” On the way, they collect some nellikai (Kannada term for Indian gooseberries) that have fallen on the ground.
Discuss with your friends and make a list of at least five products that we get from forests. Forests are a natural home for many wild animals, including birds and insects.
Forests provide food and shelter to them.
In nature, every animal depends on other life forms for survival. The diversity of life forms ensures food for every living being.
However, over the years, the forest cover has been decreasing, mainly due to human activities like large scale cutting of trees.
It takes many years to grow a new forest or restore lost forests. Therefore, we must preserve and use forests responsibly so that they get enough time to regenerate. Van Mahotsav is a week- long event celebrated across What are the consequences of the country during the month cutting a large forest area?
It is a forest festival a presentation or do a role play, during which new plants or write a story or a poem that shows what could happen
It is a forest festival a presentation or do a role play, during which new plants or write a story or a poem that shows what could happen and trees are planted, and awareness about respecting if we continue to cut down forests is raised. The aim of the trees in our forests. event is to increase the green cover.
You too can plan a Van Mahotsav in your community.
You too can plan a Van Mahotsav in your community.
From ancient times, India had a tradition of respecting, protecting and preserving forests.
Many efforts have been made by common people to prevent the cutting of trees, and thus, saving forests.
It started in the early 1970s in Uttarakhand (previously part of Uttar Pradesh).
They encircled and hugged the trees to know? protect them from being felled. During their walk in the forests, Bhoomi and Surya notice that there are a lot of leaves on the ground and the soil feels damp.
Ajji explains, “The roots of plants hold on to the soil and prevent it from being washed away.
The leaves that fall from the trees decay and enrich the soil with nutrients. This soil is used by new plants and trees to grow.
This is an example of recycling in nature.” Let us investigate the soil in more detail.
11.5 Soil, Rocks and Minerals Bhoomi, Surya and Ajji come back home from the forest. Bhoomi and Surya help Ajji in preparing the soil in the garden for planting some vegetables (Fig. Ajji asks them to dig the soil gently and loosen the lumps.
You have already learnt in the chapter ‘Living Creatures: Exploring their Characteristics’ that for plants Fig.
You have already learnt in the chapter ‘Living Creatures: Exploring their Characteristics’ that for plants Fig. 11.5: Soil preparation for to grow, the space between the planting vegetables soil particles not only provides sufficient air but also space for the roots to grow easily. Bhoomi and Surya could see small pebbles, the roots of plants and a few earthworms too in the soil.
Do you realise that earthworms are natural agents that help in turning and loosening the soil?
Do you realise that earthworms are natural agents that help in turning and loosening the soil?
While Bhoomi and Surya help Ajji, let us do our own
Remember to wash your hands Guess what could be there in thoroughly after touching the soil collected from different different soils. places.
Sometimes soil that has Observe carefully each soil sample garbage carries germs that may be harmful to us. and note its colour.
Observe the soil samples with your naked eye. If you have a magnifying lens, look at the soil through it. Record your observations in Table 11.2.
Is there any difference between your guess and what you can actually observe when you look closely? Do you see any differences in the soil samples taken from different places? Do you see differences in what you are able to observe with your naked eye and what you can observe with a magnifying lens?
There are many things in the soil, such as sand, insects and worms. There may be many small organisms that we cannot see with our naked eyes.
Plants and animals also become part of the soil as they decompose and decay.
The soil samples collected from different places may be of different colours because they may contain different materials. Have you ever wondered how soil is formed? Soil is formed by the Nature’s Treasures
disintegration (breaking apart) of rocks by actions of the Sun, water and living organisms over a long time (thousands of years).
disintegration (breaking apart) of rocks by actions of the Sun, water and living organisms over a long time (thousands of years). Some are good for growing certain types of Ploughing plants while some are good for making bricks for buildings.
Soil is a precious treasure that supports biodiversity.
Soil is a precious treasure that supports biodiversity.
You may have seen rocks in your surroundings.
Some rocks, like slate, are used for roofing (Fig.
11.6) and laterite can be used as a building material, like bricks (Fig.
Human beings have been using rocks to make tools such as hand axes (Fig. Important metals, such as aluminium, gold, copper and iron are extracted from minerals.
Minerals are used in the manufacturing of airplanes, Mining of marble cars, jewellery, cosmetics, and
For example, the basic mobile phones that we use contain about a dozen minerals like gold, silver, copper, cobalt, etc. It takes thousands to millions of years to form rocks.
Therefore, it is important to conserve and use them responsibly.
Do you know how rocks and minerals are transported from one location to another? Most vehicles that we use for transportation use fossil fuels. Let us explore more about fossil fuels.
Surya, why do that they use different types different types of vehicles go of fuels.
Surya, why do that they use different types different types of vehicles go of fuels. For to different example, petrol filling stations? and diesel. Activity 11.5: Let us conduct a survey Conduct a survey of vehicles in your neighbourhood. Which types of vehicles are there?
What types of fuels do they use? Record the information that you collect in Table 11.3.
What types of fuels do they use? Record the information that you collect in Table 11.3.
What are the most common types of fuels used?
Petrol, diesel and kerosene are obtained from petroleum.
Petroleum along with natural gas and coal are commonly called fossil fuels.
It takes millions of years for these fuels to form. Natural gas is used for cooking and generating electricity.
Nowadays, it is also used in the form of Compressed Natural
It is a cleaner fuel than petrol or diesel. Coal is mainly used for the production of electricity.
It is found in several parts of India.
Find out the major coal-producing states and mark them in a map of India. Earlier, coal, wood and dung cakes were used as fuels for cooking. Nowadays, less polluting Do you natural gas and Liquefied Petroleum Gas (LPG) have gradually replaced these domestic fuels.
Fossil fuels are found in limited quantities.
Fossil fuels are found in limited quantities. Hence, we will soon run out of fossil fuels if we continue to use them in the manner that we currently do. To avoid such a situation, we need to explore alternate sources of energy.
When fossil fuels are burnt, smoke and carbon dioxide gas are produced which pollutes the air.
When fossil fuels are burnt, smoke and carbon dioxide gas are produced which pollutes the air.
Over-dependence on fossil fuels for transportation and as domestic fuels has resulted in large scale air pollution.
11.7 Natural Resources: renewable and non-renewable Nature’s treasures fulfill our needs.
They are essential resources to sustain all life forms on the Earth.
These resources which we get from nature are called natural resources. We also use natural resources to make many useful things for our convenience.
For example, electric bulbs, furniture, Nature’s Treasures
solar panels, bicycles, etc., make our lives comfortable. All such resources created by human beings are called human-made resources.
You have learnt about various natural resources, such as air, water, energy from the Sun, forests, soil, rocks, minerals and fossil fuels.
get replenished through natural processes over a period of time. If you remember, Ajji told Bhoomi and Surya that they could collect only those nellikai that had fallen on the ground. This makes sure that there would be enough fruits for other animals and birds.
The seeds from the droppings of animals and birds would enable new trees to grow, though it would take some years before we get fruits from these new trees.
The seeds from the droppings of animals and birds would enable new trees to grow, though it would take some years before we get fruits from these new trees. Thus, resources which get renewed, replenished or restored within a reasonable period of time are called renewable resources. Air, water and forest are some of the examples of renewable natural resources.
We should use our natural resources judiciously.
We should use our natural resources judiciously.
On the other hand, fossil fuels take millions of years to form.
They are not produced or replenished within a reasonable period of time.
These resources are called non-renewable resources.
11.8 Resources we use It is time for Bhoomi and Surya to go back home after a wonderful holiday at their Ajji’s home. Their Amma (mother) comes to pick them up.
Bhoomi and Surya show her the vegetable plants that have started to grow in the garden and the dried chillies given by Ajji to take home.
They notice changes in the colour of the skyline and the smell of the air once they reach the city. The air does not smell as good as the air at Ajji’s place.
They can smell smoke from the vehicles.
When we use fossil fuels in our vehicles, smoke is generated. Now, there are vehicles which cause less pollution. For example, there are electric vehicles that do not release any smoke.
So, people are making an effort to create alternatives.” Can you list some alternatives for reducing air pollution?
So, people are making an effort to create alternatives.” Can you list some alternatives for reducing air pollution? We use many natural resources in our everyday life. Let us identify some resources that we use by performing Activity 11.6.
Activity 11.6: Let us make a list of natural resources used Make a list of activities you do in your daily life and write down the natural resources used directly or indirectly for each activity.
Activity 11.6: Let us make a list of natural resources used Make a list of activities you do in your daily life and write down the natural resources used directly or indirectly for each activity.
In Table 11.4, some items are already filled in.
How many natural resources did you list?
Compare your list with that of your friend.
These resources are air, water, soil, and food from plants and animals. We get these resources from nature and also make things using them for our consumption.
Therefore, we must conserve our natural resources and use them responsibly without wasting them.
This way, we can continue to fulfill our present needs while also saving for the future, without harming the environment. “Earth provides enough to satisfy every man’s need but not for every man’s greed.” – M.
Resources required for our survival are provided by nature. Resources provided by nature are called natural resources. Some important natural resources are air, water, energy from the Sun, forests, soil, rocks, minerals and fossil fuels. Resources created by human beings to meet their needs are
called human-made resources. Natural resources can be classified as renewable resources and non-renewable resources. Resources that get renewed, replenished or restored by natural processes within a reasonable period are called renewable resources. Resources that are in limited quantities and do not get replenished within a reasonable period are called non-renewable resources. All living beings, including humans, depend on natural resources for their survival so we should use them 226 judiciously. 11.9 shows items related to natural resources. Match them with their jumbled up names.
Make another table and write the names of these resources.
Make another table and write the names of these resources. Classify these resources as renewable or non-renewable. (i) Nature has all the resources to meet human needs. [ ] (ii) Machines are a resource found in nature. [ ] (iii) Natural gas is a non-renewable resource. [ ] (iv) Air is a renewable resource. [ ]
Fill in the blanks using the most appropriate option— (i) A fuel that is commonly used in two wheelers like scooters or bikes is.........
Fill in the blanks using the most appropriate option— (i) A fuel that is commonly used in two wheelers like scooters or bikes is.........
(a) Kerosene (b) Petrol (c) Diesel (d) LPG (ii) An example of a renewable resource is ..................
Classify the following as renewable or non-renewable resources—coal, natural gas, forests and minerals.
Why do we say that petroleum is a non-renewable resource?
Suggest ways by which you can reduce their use. List four activities that are possible due to the presence of air.
How can you contribute towards enhancing the green cover of your locality?
In the given illustration, we see that food is being cooked. (i) What type of energy is being used for cooking?
(ii) Name one benefit and one drawback of using this type of energy for cooking.
Cutting down trees on a large scale impacts the quality of the soil. Explain two ways in which human activities pollute the air. 228 Propose one action which can help in reducing air pollution.
A family uses solar panels to generate electricity, a gas stove to cook food and a windmill for pumping water from a well.
A family uses solar panels to generate electricity, a gas stove to cook food and a windmill for pumping water from a well. What would happen if there were no sunlight for a week? Fill up the blanks using the following terms— (fossil fuels, forest, air, petroleum, coal, water and non- renewable resource)
There is an increasing demand of trees to meet the requirements of industries and for housing.
There is an increasing demand of trees to meet the requirements of industries and for housing.
Propose a plan to use less water in your school.
Rainwater harvesting is an age-old practice in India.
Find out some of the traditional rainwater harvesting techniques being used in your state or in other parts of the country.
Based on your findings, suggest two practical steps that your school or community could take to help reduce air pollution. Prepare a list of the names and uses of important minerals and rocks that are used in your village/town/city for various purposes. You are an eco-club monitor. Organise a tree plantation drive in your school with the help of your teacher.
List the steps required for organising this activity.
List the steps required for organising this activity. Prepare a one-page report listing the names of the trees planted along with their importance.
Organise a tree plantation drive in your school with the help of your teacher.