A Journey through States of Water Class 6 Extra Questions and Answers Science Chapter 8

A Journey through States of Water Class 6 Extra Questions and Answers Science Chapter 8

A Journey through States of Water Class 6 Very Short Answer Type Questions

Question 1.
Write the sources of water on the earth.
Answer:
Sources of water on the earth are:
Seas, Oceans, Rivers, Springs, Tubewells, 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.
What is melting?
Answer:
The conversion of solid ice into liquid water on heating is called melting.

Question 4.
How are the clouds formed?
Answer:
Clouds are formed by the condensation of water vapour at high altitude.

Question 5.
What is meant by the conservation of water?
Answer:
Careful, economical and wise use of water and avoiding the wastage of water is called conservation of water.

Question 6.
What is condensation?
Answer:
The process of conversion of water vapours into liquid form of water is called condensation. It is reverse process of evaporation.

Question 7.
Name the three states of water.
Answer:

1. Solid state
2. Liquid state
3. Gaseous state

Question 8.
Name the phenomenon involved in fog formation during winters.
Answer:
Condensation

Question 9.
Why cannot we use ocean water directly for drinking purpose?
Answer:
Because it is salty impure water.

Question 10.
Define freezing.
Answer:
The conversion of liquid water into solid ice on cooling is called freezing.

A Journey through States of Water Class 6 Short Answer Type Questions

Question 1.
Take out a cooled bottle of water from refrigerator and keep it on a table. After some time you notice a droplets of water around it. Why?
Answer:
The cooled water bottle has very cold exposed surface. Due to cool surface there is condensation of water vapour from air on the surface of water bottle because water vapour is present in atmosphere. The condensed water molecules spread around the bottle. So a puddle of water is noticed after sometime.

Question 2.
Why is ocean water not suitable for domestic use?
Answer:
Sea and ocean water contain 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 3.
Why does the water split on the floor disappear after some time?
Answer:
Due to evaporation the water split is changed into water vapour. So it disappears after some time.

Question 4.
To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet?
Answer:
The breathe out gases contain Water vapour. The water vapour condenses at spectacles so glass becomes wet and with the help of small amount of water, it is easy to clean the spectacles.

Question 5.
Describe water cycle.
Answer:
The water present on the earth evaporates due to heating by the sun. The water vapour in the air condenses to form tiny droplets of water at high altitude, which appears as clouds. Thus clouds are formed by the condensation of water vapours present in air at high altitude.
The diagram given below presents a view of water cycle.

Question 6.
Name two processes responsible for the formation of clouds.
Answer:
Evaporation and condensation.

Question 7.
There are 4 containers A, B, C and D with same amount of water in each. Answer the following based on them.

(a) Name the container in which water will evaporate faster than all others.
(b) Name the container in which water will evaporate very slowly.
Give reason for your answer.
Answer:
(a) C – More is the exposed surfece area, more will be evaporation of water.
(b) B – As it is closed container, no evaporation takes place.

Question 8.
During winters why do we see more fog in close areas where there are lots of trees?
Answer:
Due to lots of trees, air at that place contains much more water vapour during winters. These vapour condense on dust or smoke particles forming thick fog.

Question 9.
Distinguish between evaporation and condensation.
Answer:

Evaporation	Condensation
1. This is a process of changing water from its liquid form to its vapour form.	1. This is a process of conversion of water vapour into liquid form.
2. It involves heating.	2. It involves cooling.

Question 10.
What is dew and how it is formed?
Answer:
On a clear day, water evaporates from the warm ground into the atmosphere. When night falls, the ground radiates the day’s warmth into the sky. The ground becomes much cooler, causing the water vapour to condense. This condensed vapour is dew.

Question 11.
Why should we use groundwater judiciously?
Answer:
If large quantity of groundwater is taken out for various purposes, the water level goes down. There will be lack of water in a few decades, if we continuously use water carelessly. So we should use groundwater very carefully.

Question 12.
Does evaporation take place in shade also? Give an experiment to support your answer.
Answer:
Yes evaporation takes place in shade also. Keep a plate in shade. Put some water in it. We note that water disappears slowly from the plate. The water evaporates though very slowly from the plate because of atmospheric heat.

A Journey through States of Water Class 6 Long Answer Type Questions

Question 1.
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.
Suggestions for conserving water:

• Use only the required quantity of water.
• Trees and forests help in causing rainfall. So to conserve water, we should plant more and more trees.
• By collecting rainwater in tanks, ponds or by constructing check dams.

Question 2.
Mention the factors on which rate of evaporation depends and how?
Answer:
Evaporation depends upon the following factors:
(a) Temperature
(b) Surface area of water
(c) Speed of air over the exposed surface of water
(d) Humidity Large surface area, high temperature and high speed of air increase the rate of evaporation.
Evaporation causes cooling effect. Lesser the humidity faster will be the evaporation.

A Journey through States of Water Class 6 Skill-Based Questions

Question 1.
Observe the given figure and tell what does it show.

Answer:
This figure shows that the major part of the earth is covered by the water.

Question 2.
Observe the given figure and give the answer of the following Questions:
(i) What does this figure show?
(ii) How do the clothes dry in sunlight?

Answer:
(i) This figure shows the drying of clothes in sunlight.
(ii) In the sunlight the rate of evaporation of water is increased due to which the clothes are dried very soon in the sunlight.

Question 3.
Draw a diagram to show drops of water on the outer surface of the glass containing water and enough ice and explain why do these drops form?
Answer:
The air contains water vapour. When this water vapour comes in the contact with the cool surface of glass which contains very cold water then the condensation of vapours takes place. Thus the drops of water are v’ formed on the surface of glass containing water and enough ice.

Drops of water appear on outer surface of the glass containing water with ice

Question 4.
Draw a diagram to show the clouds in nature.
Answer:

Clouds

Question 5.
Complete the given flow-chart.

Answer:

Question 6.
Observe the following figure and tell what does it show?

Answer:
This figure shows a queue for collecting water where there is shortage of drinking water.

A Journey through States of Water Class 6 Case Based Questions

Question 1.
Physical change is when a substance changes from one physical state to another without change in its composition. Several processes bring about physical changes like evaporation, condensation, boiling, melting, freezing, etc.

• Evaporation is the process of change in state from liquid to a gaseous state.
• Condensation is the process of change in state from a gaseous state to a liquid state.
• Evaporation is observed during salt formation from water bodies and Condensation is observed in clouds.
• Evaporation and condensation are basically opposite processes of each other.

I. What factors affect the phenomenon of evaporation?
Answer:
Evaporation is the process through which liquids turn into vapour. Temperature, surface area, wind speed and humidity are the variables that influence the rate of evaporation of liquids.

II. Write down three differences between evaporation and condensation.
Answer:
Differences between condensation and evaporation:

Condensation	Evaporation
1. Gas changes to liquid.	1. Liquid changes to gas.
2. Heat loss (accompanied by cooling). Molecules lose energy.	2. Heat gain (accompanied by heating. Molecules gain energy.
3. Occurs at a low temperature.	3. Occurs at a higher temperature.
4. Occurs at high altitude places like mountains.	4. Common in places of low altitude like sea level places.

III. Write down any three applications of evaporation in our daily life.
Answer:

1. Wet clothes diy under the sun due to evaporation.
2. Salt is produced by the evaporation of seiline water obtained from various natural sources.
3. The acetone present in the nail paint remover takes the heat of our bodies and evaporates.

IV. Write down any three applications of condensation in our daily life.
Answer:

1. Water droplets seen on the grass in early mornings are due to condensation.
2. Clouds are formed due to condensation of various gases present in the atmosphere.
3. Evaporated water vapours condense in the clouds to fall as rain or snow.

Question 2.
Water cycle has a huge impact on determining the global climate. It is also an integral part of other biogeochemical cycles. It affects all life processes on Earth either directly or indirectly. The water from the ocean and the Earth’s surface evaporates into the atmosphere as vapour and returns as rain, hail or snow, ultimately flowing back to the ocean. This circulation of water is known as the water cycle.

I. What is the importance of water cycle?
Answer:
The water cycle is important for us because of the following reasons:

• Water cycle helps in regulating weather on earth.
• Water cycle makes water available in its various forms on the earth. The most important is the rainwater.

II. Label the given figure using arrows shown and the words given in the box to show where water is stored, how water changes its state and where it moves.
Cloud, Lake, Ocean, River, Groundwater, Evaporation, Condensation, Rain, Collection

Answer:

III. In what ways the oceans are crucial for the water cycle?
Answer:
The oceans play a vital role in the case of the water cycle. They are the main reservoirs of water from where it gets evaporated. Moreover, the oceans are the first to receive the rains when the water condenses. Without the presence of oceans, the water cycle would not take place properly.

Class 6 Science Extra Questions