A Journey through States of Water Class 6 Questions and Answers NCERT Solutions
Class 6 Science Chapter 8 A Journey through States of Water Question Answer
Let Us Enhance Our Learning
Question 1.
Which of the following best describes condensation?
(i) The conversion of water into its vapour state.
(ii) The process of water changing from a liquid into gaseous state.
(iii) The formation of clouds from tiny water droplets.
(iv) The conversion of water vapour into its liquid state.
Answer:
(iv) The conversion of water vapour into its liquid state describes condensation.
Question 2.
Identify in which of the given process, evaporation is very important.
(i) Colouring with
(a) Crayons
(b) Water colours
(c) Acrylic colours
(d) Pencil colours
Answer:
(b) Water colours
(ii) Writing on paper with
(a) Pencil
(b) Ink pen
(c) Ball point pen
Answer:
(b) Ink pen
Question 3.
We see green coloured plastic grass at many places these days. Space around natural grass feels cooler than space around the plastic grass. Can you find out why?
Answer:
Space around natural grass feels cooler because it absorbs heat from the sun and undergoes the process of transpiration and evaporation, which gives a cooling effect. Whereas, the plastic grass does not undergo such processes of evaporation and transpiration, so, it does not give a cooling effect.
Question 4.
Give examples of liquids other than water, which evaporate.
Answer:
Sanitizer(alcohol), acetone, petrol, ether, etc. are examples of liquids other than water, which evaporate.
Question 5.
Fans move air around, creating a cooling sensation. It might seem strange to use a fan to dry wet clothes since fans usually make things cooler, not warmer. Normally, when water evaporates, it requires heat, not cold air. What do you think about this?
Answer:
Fans move the air faster around clothes and help these to dry faster because water evaporates faster.
Question 6.
Usually, when sludge is removed from drains, it is left in heaps next to the drain for 3-4 days. Afterward, it is transported to a garden or a field where it can be used as manure. This approach reduces transportation cost of the sludge and enhances the safety of individuals handling it. Reflect upon it and explain how.
Answer:
The sludge is removed from drains is wet so it is kept in the forms of heaps next to the drain for 3-4 days. Meanwhile it gets dried due to evaporation and all extra water gets drained out. This moisture free sludge is safe as it is free from harmful microorganisms and then it is transported to a garden or a field where it can be used as manure.
Question 7.
Observe the activities in your house for a day. Identify the activities that involve evaporation. How does understanding the process of evaporation help us in our daily activities?
Answer:
The activities are:
- We sprinkle water on the roof or open ground in summer.
- We wear cotton clothes in summer.
- Perspiration keeps our body cool.
- Water kept in earthen pot becomes cool. Thus, evaporation helps us in our daily activities.
Question 8.
How is water present in the solid state in nature?
Answer:
Water is present in the solid state in nature as
Ice It is found in ice caps, glaciers etc.
Snow It is found in mountains.
Hail It is a form of solid precipitation that falls as balls of ice.
Frost A thin layer of ice that forms on a cold surface, when the temperature is less than 1°C.
Question 9.
Reflect on the statement “Water is our responsibility before it is our right.” Share your thoughts.
Answer:
Enough water is available on the earth but the water available for use is very limited and is decreasing with over-usage. On the other hand, due to increase in human population, demand of water usable for drinking, preparation of food and also for industries, is increasing. Most of water in the oceans cannot be used directly as it is salty and unclean. Thus, it is our responsibility to save water and use it properly.
There is a strong need to conserve water, use it carefully and economically. Also avoid unnecessary wastage of water. Conservation programmes can be successful, if all people follow them faithfully.
Question 10.
The seat of a two-wheeler parked on a sunny day has become very hot. How can you cool it down?
Answer:
To cool down the hot seat of a two-wheeler parked on a sunny day, we can:
- Cover it with a wet cloth: Place a damp cloth or towel over the seat. The water will absorb heat as it evaporates, cooling the seat.
- Sprinkle water on it: Lightly sprinkle water directly on the seat. The evaporating water will help to lower the temperature.
- Use a sunshade or cover: If available, use a sunshade or seat cover to protect the seat from direct sunlight, which will help keep it cooler.
- Park in the shade: If possible, move the two-wheeler to a shaded area to reduce the seat’s exposure to direct sunlight.