Unit 5: Science and Experiment

Reading – I

Yes, You Can Boil Water at Room Temperature

A. Find the words from the text that have the following meanings.

B. Complete the sentences with the correct words or phrases from the text.

a. Water bubbles break down if vapour pressure inside and outside the bubbles is equal.

b. As the altitude goes up, the boiling point of water decreases.

c. Random motion of molecules or particles is called thermal motion.

d. If the door does not open, try pushing the key in the lock.

e. Certain chemicals can induce undesirable changes in the nervous system.

C. Answer these questions.

a. What is the speed of the water particles compared with?

=> Answer: The movement of water particles is compared with the thermal motion of tiny balls, which represent the molecules of water.

b. How are bubbles formed in the boiling water?

=> Answer: The addition of heat increases the energy and movement of water molecules. When their energy becomes sufficiently high, some molecules separate from the surrounding liquid and produce spaces filled with water vapour. These vapour-filled spaces are observed as bubbles.

c. Mention two things on which external pressure depends.

=> Answer: External pressure depends on the altitude above sea level and the atmospheric conditions around the liquid.

d. How is the atmosphere related to the pressure of water?

=> Answer: The atmosphere exerts pressure on the surface of water. Boiling takes place when the vapour pressure within the water bubbles becomes equal to the atmospheric pressure outside the bubbles.

e. What would happen if the atmospheric pressure on the liquid water was decreased?

=> Answer: When atmospheric pressure is lowered, water molecules can escape from the liquid more easily. As a result, vapour bubbles can develop at a lower temperature, causing the boiling point of water to decrease. If the pressure is sufficiently reduced, water can even boil at room temperature.

f. What would the experimenter gain if she pulled the plunger out?

=> Answer: Pulling the plunger outward would lower the pressure inside the syringe. This reduced pressure would help water molecules form vapour bubbles more easily, causing the water to boil without requiring a considerable increase in temperature.

D. What would happen on the Earth if there were no gravity?

If gravity vanished from Earth, the force responsible for keeping people and objects on the ground would disappear. Human beings, buildings, trees and other objects would begin to float away from the Earth's surface. Water would also be unable to remain normally in rivers, lakes and other places. Consequently, familiar phenomena such as rainfall and flowing rivers would be greatly affected. People could neither walk nor stand normally because nothing would pull them towards the ground. The atmosphere would also not be retained around Earth in its present form. Life would therefore become extremely different, resembling life inside a spacecraft where there is no gravitational force to keep objects in place.

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Grammar I

A. Match the clauses with their appropriate continuation.

B. Complete the following sentences using the correct form of verbs in brackets.

a. If it is cold, I will wear a coat.

b. If Purna helps with the housework, his mother will have more time for him.

c. If I were a bird, I would make a good observation of the land below.

d. If I went to Mustang, I would visit Muktinath.

e. If I were a billionaire, I would buy a castle.

f. You'd save petrol if you drove more carefully.

g. Say 'hello' if you see her.

h. Provided that you consent, I will take a few days' leave next week.

i. Take care of the pence, the pounds will take care of themselves.

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Writing I

Write stepwise instructions to draw a jellyfish as given below.

Reading – II

Voice of the Rain

A. Match the words with their meanings.

B. Fill in the blanks by choosing the words given below.

[impalpable, recks, globe, drought, beautify, latent]

a. The river ran dry during the drought.

b. It is still impalpable to understand how the earth originated.

c. The company produces a wide variety of make-up and skin care products designed to gently and effectively beautify human skin.

d. His greatest ambition is to sail around the globe.

e. Without training, his musical talent remained latent.

f. What recks it whether they win or lose?

C. Complete the summary of the poem using suitable words or phrases given below.

[quenches, rhythm, mysterious, heal, atomies, condensation, ascends, showers, originality]

The poem is a conversation between the poet and the rain. When the poet asks about the identity of the drizzle, she replies that she is the poem of the Earth. The rain expresses that it gives happiness to Mother Earth.

The rain is a perpetual process which has different forms at different times. It rises from the land as water vapour and ascends high up to the sky. It takes the form of clouds. Though it changes its form or shape, its originality remains unchanged. It shows that nature is not fully understood. Some parts of it always remain mysterious.

The raindrops pour down from above to wash away atomies and dust layers. It quenches the thirst of the dry Earth and heals everything that is becoming lifeless. In other words, the showers make the Earth pure and beautiful.

Finally, the poet observes that the life of rain is similar to that of a song. A song also has the power to calm, heal, transform and thrill. In the same way, repeated evaporation and condensation purifies the rain. It beautifies the whole earth as a rhythm does to a poem or music.

D. Answer the following questions.

a. What are the two voices in the poem? Who do they belong to?

=> Answer: The poem presents two voices in the form of a dialogue. One voice is that of the rain, and the other belongs to the speaker, Walt Whitman.

b. How is the cycle movement of the rain shown in the poem?

=> Answer: The recurring movement of rain is expressed through its transformation and return to the Earth. Water rises as vapour, takes the form of clouds in the atmosphere and eventually comes down as rain. The poem also presents different sounds and intensities of rainfall, showing its continuous movement through nature.

c. Why are the showers necessary for the Earth?

=> Answer: Showers are necessary because they provide water that sustains life. They refresh dry land, help plants and other living things grow, remove dust and impurities, and bring renewed energy to the natural environment.

d. How are the rain and music similar?

=> Answer: Rain is compared with music because both possess expressive sounds and rhythm. The rain seems to sing and murmur as it falls, while music also depends on sound and rhythm. Both can soothe, heal, refresh and create pleasurable feelings.

e. How are the clouds formed?

=> Answer: Clouds are formed through the cooling of moist air. Warm air carrying water vapour rises upward and becomes cooler. The vapour then changes into tiny droplets through condensation. These droplets gather together and form clouds.

f. List the pairs of opposite words in the poem.

• •
  rise / descend
• •
  rain / drought
• •
  day / night
• •
  reck'd / unreck'd (recked / unrecked)

C. Why do water and vegetable oil not mix?

Water and vegetable oil do not mix because their molecules possess different characteristics. Water molecules have slightly positive and negative regions, allowing them to attract one another strongly. This attraction keeps the molecules closely connected.

Oil molecules do not contain the same positive and negative regions found in water. Therefore, they do not interact strongly with water. Instead, oil molecules remain associated with other oil molecules.

When the two liquids are combined, their different molecular behaviour causes them to separate. Water stays together while oil forms a separate layer, preventing the formation of a uniform mixture.

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Grammar II

A. Complete the following sentences using the correct form of verbs in brackets.

a. If Gaurab were the captain, the team would play better.

b. I would have called you had I known you were in Nepal.

c. If he didn't come to Nepal, he would not have seen Mt. Everest.

d. Had you arrived a bit earlier, you would have seen Manashi.

e. We could slow down global warming if we reduced energy consumption.

f. If he were to see me, he would know me at once.

g. Were Rijisa in the USA, she would be working for a company.

h. How would you feel if someone asked you for an autograph?

i. What would you have done if Keshab had proposed you for marriage?

j. If I had a life jacket, I could certainly swim across the river.

B. Complete the following sentences with appropriate clauses.

a. If you don't leave soon, you will miss your bus.

b. If it rains in winter, you will feel colder.

c. You will not get into trouble as long as you tell the truth.

e. A country cannot develop unless it invests in education and infrastructure.

f. What will you do if they insult you?

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Writing II

Write a letter of complaint to the concerned authority about the unmanaged garbage in your locality. Mention the hazards of unmanaged garbage to public health and suggest some measures to solve the problem.