NCERT Solution for Class 6 Science Chapter 8 A Journey through States of Water

NCERT Solution for Class 6 Science Chapter 8 A Journey through States of Water जल की विविध अवस्थाओं की यात्रा 

(Page 154) (पेज 146)

Question 1.
Reflect on what you did really well in this activity. 
इस बात पर विचार करें कि आपने इस क्रियाकलाप में वास्तव में क्या अच्छा किया। 
Answer:
We increased the exposed area in the case of water in the plate. Water in the bottle had lesser exposed area. It was found that water evaporates faster as the exposed area increases.
प्लेट में पानी की स्थिति में हमने खुला हुआ क्षेत्रफल बढ़ा दिया। बोतल में पानी का खुला हुआ क्षेत्रफल कम था। यह पाया गया कि खुला हुआ क्षेत्रफल बढ़ने पर पानी तेजी से वाष्पित होता है।

(Page 159) (पेज 152)

Question 2.
What did I do well? Was I able to label all the parts of the water cycle? Which parts of the water cycle were unclear to me? 
मैंने क्या अच्छा किया? क्या मैं जल चक्र के सभी भागों को नामांकित करने में सक्षम था/थी? जल चक्र के कौन-से भाग मुझे स्पष्ट नहीं थे?
Answer:
We could label some parts of water cycle. It was difficult to distinguish between lake and river water. Also labelling ground water is difficult.
हम जल चक्र के कुछ भागों को नाम दे सकते थे। झील और नदी के जल में अंतर करना मुश्किल था। साथ ही, भू-जल को नाम देना भी कठिन है।

Let Us Enhance Our Learning (Pages 161-162) (पेज 154-155)

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.
निम्नलिखित में से कौन-सा संघनन का सबसे अच्छा वर्णन करता है?
(क) जल का वाष्प के रूप में परिवर्तन। 
(ख) जल का द्रव से गैसीय अवस्था में बदलने का प्रक्रम। 
(ग) छोटी जल की बूंदों से बादलों का बनना। 
(घ) जल वाष्प का उसकी द्रव अवस्था में परिवर्तन। 
Answer:
(iv) The conversion of water vapour into its liquid state is called condensation.
(घ) जल वाष्प का उसकी द्रव अवस्था में परिवर्तन संघनन कहलाता है। 

Question 2.
Identify in which of the given processes, evaporation is very important-
(i) Colouring with
(a) crayons
(b) water colours
(c) acrylic colours
(d) pencil colour
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:
Water is lost from the natural grass from the aerial part of the leaves (transportation) and evaporation. Evaporation causes cooling effect.

Question 4.
Give examples of liquids other than water, which evaporate.
Answer:
Milk, oil, whisky, eye drops, sanitizer.

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:
Blowing fan on wet clothes can fasten the drying process. When you blow air over wet clothes, the moving air helps to increase the rate of evaporation. This happens because the air moving across the wet surface helps to carry away the water vapour that is evaporating from the clothes, creating a drier environment around the clothing.
This air-flow helps to reduce the humidity and hence speeds up the rate of evaporation.

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:
Water (moisture) from the sludge evaporates with time making it handling and transportation easier.

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:
Refer to the text in section 8.5 and 8.6 to understand the examples and process of evaporation in daily life.

Question 8.
How is water present in the solid state in nature?
Answer:
Water in the solid form occurs as ice and snow on the peaks of mountains and in the polar regions such as Antartica.

Question 9.
Reflect on the statement “Water is our responsibility before it is our right.” Share your thoughts.
Answer:
Only a small portion of water available on earth is fit for use by plants, animals and humAnswer:Most of the water is available in the oceans which we cannot use directly. We need water for drinking and many other activities. With increasing population the availability of safe water is decreasing. Though it is our right to get water’for our existence but at the same time it is our responsibility to keep water bodies free from pollution.

Question 10.
The seat of a two-wheeler parked on a sunny day has become very hot. How can you cool it down?
Answer:
First of all move your two-wheeler into a shade under the tree, then you can keep a wet handerkerchief or cloth on th,e seat so that due to evaporation it gets cooled. Or you can pour cold water on the seat and let it gets evaporated or wipe it out.