Class 6 Science Chapter 14 Important Questions
Class 6 Science Chapter 14 Important Questions of Water. Class 6 Science Extra Questions Answers are prepared for academic session 2020-2021. These sets of important Extra Questions for class 6 science chapter 14 includes long questions, short question and very short questions with answers.Suggested answers of all the questions are given here with suitable example and explanation.
Class 6 Science Chapter 14 Important Questions for 2020-2021
Class 6 Science Chapter 14 Important Extra Questions Answers
- Write down the common activities which require water in our everyday life.
Apart from drinking, there are so many activities for which we use water. Such as drinking, brushing, bathing, washing utensils, washing clothes, cleaning floor, gardening and so on.
- How will you get an idea of how much water your family uses in a day?
Using this information, calculate the amount of water needed by your family in a day. Now, divide this amount by the number of members of your family. This will give an idea of the amount of water needed by one member of your family in a day.
- Write any two activities which require more than a bucket of water.
Two activities which require use of more than one bucket of water, as:
(i) Washing more than 10 clothes and
(ii) Irrigation a crop field.
- Where do we get water from?
We draw water from a river, spring, pond, well or a hand pump”. We also get water from taps. Water that we get from taps is also drawn from a lake or a river or a well. It is then supplied through a network of pipes. Each of us may be getting water into our homes in different ways. But, finally, all of us get water from the same sources.
- Water kept in in sunlight gets heat from the sun and is evaporated. But how does water kept under the shade of a tree also gets evaporated? Explain.
Water kept under the shade of a tree also evaporates because of warm air. Actually, during day time, the heat given out by the sun heats all the air around us. This warm air provides heat for evaporation of water kept in the shade.
How can we conserve water? State different uses of water.
We can conserve water by following ways:
- (i) Do not waste water and repair all the leaking water taps.
- (ii) Do not use drinking water in garden or in cleaning.
- (iii) Do not throw any waste in ponds or rivers to prevent their pollution.
- Water is used:
(i) For drinking and cooking.
(ii) For bathing and cleaning.
(iii) In agriculture, to produce food.
(iv) In industries, to perform different activities.
(v) For generating electricity.
- Write down the advantages of rains.
Rains bring relief by cooling the environment after hot summer days. The sowing of many crops depends on the arrival of rains during monsoon. Rains provide water in the rivers and dams of hydroelectric power plants. Rains fill the lakes and ponds which act as sources of water. Rains are also responsible for the underground water which gets stored under the surface of earth.
- Write any two activities which require less than one bucket of water.
Two activities which require use of less than one bucket of water, as:
(i) Brushing teeth and
(ii) Washing a handkerchief.
Why is there a need for conserving water? Give two reasons.
There is a need for conserving water because of the following reasons:
- Increasing population is creating more demand for usable water.
- Availability of freshwater is decreasing day-by-day.
- Most of the water that falls on the land as rain and snow, sooner or later goes back to a sea or an Ocean. Explain how it happens.
Snow on the mountain melts into water. This water flows down the mountains in the form of rivers and streams. A part of the rain water gets absorbed into the ground and rest flow in the form of streams or rivers. Most of the river cover long distances on land after passing through various regions and ultimately reach into a sea or an ocean.
- “The excessive rainfall due to heavy rains lead to many problems”. Comments.
Heavy rains in city areas lead to waterlogged roads and streets. This disrupts the traffic on roads and causes inconvenience to the people. Heavy rains or excessive rains may cause floods. This happens as, heavy rains lead to too much rise in the level of water in river. The river water starts overflowing from its banks and spread over a large area of land causing floods. The flood water may submerge cities, villages, crops fields and forests causing damage to property, human life, domestic animals and wild animals of the forest.
The animals living in water are carried away by the fast-flowing flood waters. These water animals often get trapped on land areas and when the flood water recedes, they die. Heavy rains also kill the animal living inside the soil.
- Why do wet clothes placed on a clothes line dry after some time? Explain.
Wet clothes placed on a clothes line dry after sometime because water present in wet clothes is converted into water vapour and released in atmosphere due to evaporation which leaves them dry.
- What do you mean by transpiration?
Plants need water to grow. Plants take this water from the soil for their food and the remaining water is released by the plants into air as water vapour through stomata. The loss of water from plants as water vapour through the pores of their leaves is called transpiration.
- Explain the formation of Cloud?
The condensation plays an important role in the formation of Clouds. The water vapours, that go into air, rise up along with air. As the air moves up, water vapour get cooler and cooler. At sufficient heights, air becomes so cool that the water vapour is present in it condense into tiny droplets of water. When these water droplets come-closer they combine to form slightly bigger droplets. In this way, their size becomes larger. Once the size of these droplets become large, they collectively appear to us as clouds.
What do you mean by drought? Explain.
Sometimes, it happens that if there is no rain in a region for a year or more. This leads to shortage of water in that region causes dryness everywhere. An environment of dryness is called drought. As we can say that if it does not rain in a region for a long time it causes drought.
Due to lack of rains, the water level in the lakes and ponds also goes down and some of them may even dry up completely. In the absence of rain, no water seeps into the ground and hence the level of groundwater in wells etc., falls drastically. Due to this the groundwater also becomes scarce. In this way, a prolonged period of no rains or very low rains causes all around shortage of water leading to drought.
- What do you mean by condensation?
The mass of tiny droplets formed by the condensation of water vapour which we see floating high in the atmosphere is called cloud. The formation of clouds involves the process of condensation. The changing of water vapour into liquid water on cooling, is call condensation.
- Why do some water pipes burst in winter? Is cutting of trees responsible for droughts and floods?
Some water pipes burst in winter because during winter, cold develops enormous pressure in the pipes and due to this high pressure, water pipes burst. Yes, cutting of trees are responsible for droughts and floods. Cutting of trees disrupts the natural water cycle. Trees are natural water tanks. They absorb water during rain. When we cut trees, water can’t absorb. So, it has to go where gravity takes it, which causes flood. Deforestation and soil erosion would dry up the place where it happens, since water is not absorbed. This causes drought.
What are the advantages of water harvesting?
Advantages of water harvesting:
- i) In areas where there is very low rainfall, water harvesting is the only way to reduce the water shortage.
- ii) There is an increase in the level of groundwater.
- iii) The effect of drought is lessened.
- iv) Places not situated near a river or large lakes have to rely on ground water. Water harvesting is very important in such areas.
- v) Water logging of low-lying roads and street is prevented.
- vi) Soil and water pollution are reduced.
Explain the role of plants in adding water vapours into atmosphere.
In nature, there is another process through which water vapour gets transferred into the air. This process involves plants. All plants need water to grow. Plants get this water from the soil, which is absorbed from it by their roots. A part of this water is used by them to prepare their food. Some water is retained by different parts of the plants like roots, stem, leaves, flowers and fruits. However, a large part of this water is released by the plants into air as its vapour. Most of the water lost by the plants in this process is through their leaves. This process is known as transpiration.
Every plant whether it is in a crop field, a forest, on the roadside or in a kitchen garden transpire to give off water vapour. The amount of water vapour that goes into the air through the process of transpiration is very huge. To give an idea, let us consider an example. Suppose a crop of cone has been sown in a plot which is 100 metre-long and 100 metre-wide. The amount of water that that crop of corn would loss through transpiration during one season would be roughly in a 90 cm high tank spread over the plot of land.
Water lost through transpiration by wheat plants that give us one kilogram of wheat is roughly 25 large sized-bucket full of water, that is nearly 500 litres. Thus, we can see that water vapours get continuously added to air by the plants during the process of transpiration.
Write four sentences to conserve water.
- Water is a precious gift of nature. We should not waste it. Try to save every drop of water.
- Always be careful that water tank in your house does not overflow when it is being filled.
- If we leave the tap running while brushing our teeth, nearly 16 litres of water get wasted. We should fill a mug of water and use that instead.
- We should not water our garden by drinking water instead we have to reuse the water from washing clothes and cleaning utensils.
Briefly describe the water cycle also explain its importance.
Water on heating turns into water vapour. Water vapour on cooling gives water again. The change of water from one form to another form over and over again makes the water cycle in nature. The sun heats up and evaporates the water from oceans, ponds, lakes and rivers. This water vapour being lighter is carried up by the air. This water vapour gets cooled at height and water droplets are formed. These water droplets from a cloud. When this water droplets, come close together they form drops of water. These drops of water may fall on the earth as rain.
The rain is absorbed by the soil. A part of rainwater collected in the rivers flows into the sea, where again the evaporation occurs. This completes the water cycle. Thus, now we know how water gets circulated between the oceans and lands through evaporation, transpiration, precipitation and its downhill flow by different routes. This process of circulation of water is known as water cycle.
Water cycle helps in maintaining continuous supply of freshwater to all living things on land. No, life on land would have been possible without water cycle.
What do you mean by rainwater harvesting?
The activity of collecting rainwater directly and store it in big tanks for later use, or making the rainwater percolate into ground more efficiently to recharge the groundwater, is called rainwater harvesting.
There are two main techniques of rainwater harvesting, as collection and storage of rainwater in tanks for future use and second is, to make rainwater percolate into the ground more efficiently.
Water cycle keeps the amount of water on the earth’s surface constant. How?
This is because the water removed from the earth during evaporation and transpiration is put back to the earth during rain and snowfall.
Why sea water is not fit for drinking?
The water in the oceans and seas has many salts dissolved in it — the water is saline. So, it is not fit for drinking and other domestic, agricultural and industrial needs.
Boojho wants to know from Paheli, that how much water is lost through transpiration by wheat plants that give us one kilogram of wheat?
Paheli says that this is nearly 500 litres, that is, roughly 25 large sized buckets full of water.