Unit 5: Science and Experiment

Science begins with a question and an experiment. In this unit a popular-science article answers a surprising question — can water boil without being hot? — and an American poem lets the rain itself explain the cycle that science calls evaporation and condensation. You will learn to talk about possible and imaginary situations with conditional sentences, to write instructions and to write a letter of complaint to the editor.

5.1 Yes, You Can Boil Water at Room Temperature

About the text

This is a popular-science article. It takes a common belief — "water boils at 100 °C" — and shows that this is true only at one particular pressure. The writer calls the belief a factoid (a piece of unreliable information that is repeated so often that people accept it as fact) and explains, step by step, why boiling depends on pressure as well as temperature. The style is clear and explanatory: it asks questions, gives a reason, then proves it with an experiment anyone can imagine.

What the text says

1. What boiling is. Water is made of molecules that are always moving; this random movement is called thermal motion. At any temperature some molecules move faster than others. When water is heated, more molecules gain enough energy to escape from the liquid as vapour.
2. Bubbles. Boiling is the point at which bubbles of vapour form inside the liquid. A bubble can form only if the vapour pressure inside it is high enough to push back the water around it. So water boils when its vapour pressure equals the external pressure on it.
3. External pressure. The pressure on a bubble comes from two sources: the weight of the water above it (it depends on the depth and the density of the water) and the atmosphere pressing on the water surface.
4. Change the pressure, change the boiling point. At sea level, atmospheric pressure is high, and water boils at 100 °C. At higher altitude the air above is thinner, so the pressure is lower and water boils at a lower temperature. If the pressure above the water is reduced even more, the water can boil at room temperature.
5. The plunger experiment. Put some warm water in a syringe, seal its nozzle and pull the plunger out sharply. The space above the water becomes close to a vacuum; the pressure falls; the water starts to boil, with bubbles, at a temperature far below 100 °C. When the plunger is pushed back, the vapour condenses again and boiling stops.
6. Balance. Boiling stops when the vapour pressure and the outside pressure are in equilibrium.

The article's lesson: boiling is not only a matter of "how hot", but of "how hot compared with the pressure".

Why it matters — some real numbers

Place	Approximate height	Water boils at about
Sea level	0 m	100 °C
Kathmandu	1,400 m	95 °C
Namche Bazaar	3,440 m	89 °C
Summit of Mount Everest	8,849 m	about 71 °C

(The boiling point falls roughly 1 °C for every 300 m of height. The values are approximate.) This is why rice takes longer to cook in the mountains and why a pressure cooker, which raises the pressure so that water boils above 100 °C, saves fuel and time in Nepali kitchens.

Vocabulary

Word	Meaning	Example
altitude	height above sea level	Altitude sickness affects climbers.
molecule	a group of atoms bonded together	A water molecule is H₂O.
equilibrium	a state in which opposing forces are balanced	The two forces are in equilibrium.
condense	to change from gas or vapour to liquid	Steam condenses on a cold lid.
factoid	an unreliable "fact" repeated so often that it is accepted	That we use 10 % of our brain is a factoid.
vacuum	a space with the air removed	There is almost a vacuum in the syringe.
plunger	a device that is pushed and pulled (here, in a syringe)	He pulled the plunger back.
induce	to cause or bring about	Certain chemicals can induce sleep.

Questions and model answers

Objective questions (1 mark each)

1. Water boils when its vapour pressure is equal to [1]aroom temperaturebthe external pressurecits densitydits volume
2. As altitude increases, the boiling point of water [1]arisesbfallscstays the samedbecomes 100 °C
3. The random motion of molecules is called [1]athermal motionbgravityccondensationdequilibrium
4. "Factoid" means [1]aa proved factba false belief repeated as a factca small factda fraction

Answers

1. (b).

2. (b).

3. (a).

4. (b).

Short-answer questions (2 marks each)

1. How are bubbles formed in boiling water? [2]
2. Mention two things on which external pressure depends. [2]
3. How is the atmosphere related to the pressure in water? [2]
4. What would happen if the atmospheric pressure on liquid water were decreased? [2]
5. What would the experimenter gain by pulling the plunger out? [2]

Model answers

1. Bubbles form when water molecules gain enough energy to turn to vapour inside the liquid, and the vapour pressure is strong enough to push back the surrounding water.

2. It depends on the depth of the water and the density of the water (and on the pressure of the air above it).

3. The atmosphere presses on the surface of the water, and this pressure adds to the pressure inside the liquid.

4. Boiling bubbles would form at a lower temperature, so the water would boil below 100 °C.

5. Pulling the plunger lowers the pressure above the water, so the water starts to boil even at room temperature.

Long-answer question (4 marks)

1. Explain why water boils at room temperature in a syringe when the plunger is pulled. [4]

Model answer

1. Water boils when its vapour pressure equals the pressure outside it. In a closed syringe the pressure above the water is that of the air. When the plunger is pulled out sharply, the space above the water becomes almost a vacuum, so the outside pressure falls greatly. The warm water's vapour pressure is now higher than the pressure outside, so vapour bubbles form inside it — the water boils, even though it is far below 100 °C. When the plunger is released, the pressure rises again, the vapour condenses and the boiling stops.

5.2 The Voice of the Rain

About the poet and the poem

Walt Whitman (1819–1892) is one of America's greatest poets. His long collection Leaves of Grass, which he revised all his life, celebrates ordinary people, nature and democracy in free verse — verse without rhyme or regular metre. "The Voice of the Rain" is a short poem in this style. Its form is a dialogue: the poet asks a question and the rain answers in its own voice.

The poem

And who art thou? said I to the soft-falling shower, Which, strange to tell, gave me an answer, as here translated: I am the Poem of Earth, said the voice of the rain, Eternal I rise impalpable out of the land and the bottomless sea, Upward to heaven, whence, vaguely form'd, altogether changed, and yet the same, I descend to lave the droughts, atomies, dust-layers of the globe, And all that in them without me were seeds only, latent, unborn; And forever, by day and night, I give back life to my own origin, and make pure and beautify it; (For song, issuing from its birthplace, after fulfilment, wandering, Reck'd or unreck'd, duly with love returns.)

Meaning

• Lines 1–3: the question. The poet asks the gentle shower who it is. The rain answers, "I am the Poem of Earth": a poem of the earth, made by the earth itself.
• Lines 4–5: the upward journey. The rain rises, as invisible vapour, from land and the "bottomless sea" to heaven, where it takes shape as cloud — changed in form, "yet the same". (This is evaporation and cloud formation.)
• Lines 6–8: the return. It descends to wash the dry land and its dust, and gives life to seeds that without it would stay "latent, unborn". It returns to its origin to purify and beautify the earth. (This is precipitation.)
• Lines 9–10: the comparison with song. A song leaves the singer, travels, is heard or not heard ("reck'd or unreck'd"), and in time returns to the heart with love, just like rain returning to the earth. Rain and poetry, both are cycles of giving and returning.

The water cycle in the poem

Poetic devices

Device	Example	Effect
Personification	the rain speaks and says "I am the Poem of Earth"	Nature is given a voice and personality
Metaphor	"I am the Poem of Earth"	Rain is described as a poem — beautiful and life-giving
Simile-like comparison	song returns "with love" as rain returns to earth	Joins nature and art
Free verse	no rhyme, long lines	A natural, flowing speech-like rhythm
Antithesis (opposites)	rise / descend; day / night; seeds / unborn	Shows the complete cycle
Parenthesis	the last two lines in brackets	Adds an afterthought that explains the comparison

Vocabulary

Word	Meaning
eternal	never-ending
impalpable	that cannot be touched or felt; very fine
vaguely	not clearly
descend	to come down
lave	to wash or pour over
atomies	tiny particles of dust (also atomizes in some texts)
latent	present but hidden and not yet active
reck	to care about or take notice of
drought	a long period without rain
globe	the Earth
beautify	to make beautiful

Questions and model answers

Objective questions (1 mark each)

1. Who wrote "The Voice of the Rain"? [1]aRabindranath TagorebWalt WhitmancWilliam WordsworthdAmy Lowell
2. "Impalpable" means [1]aheavybnot able to be touched or feltclouddbright
3. According to the poem, the rain is the [1]aSong of the SeabPoem of EarthcVoice of GoddQueen of Clouds
4. The figure of speech in "The rain said, 'I am the Poem of Earth'" is [1]apersonificationballiterationchyperboledonomatopoeia

Answers

1. (b).

2. (b).

3. (b).

4. (a) — the rain speaks like a person.

Short-answer questions (2 marks each)

1. What are the two voices in the poem? Who do they belong to? [2]
2. How is the cyclic movement of the rain shown in the poem? [2]
3. Why are showers necessary for the earth? [2]
4. How are the rain and a song similar? [2]
5. List some pairs of opposite words from the poem. [2]

Model answers

1. The two voices are the poet's (who asks) and the rain's (who answers).

2. The rain rises as vapour from land and sea to heaven, changes form as cloud, then descends to the earth and returns to its origin.

3. Showers wash the dust and drought of the land and bring life to seeds that would otherwise remain hidden.

4. A song leaves its birthplace and, after wandering, returns with love, just as the rain rises and returns to the earth; both give life and beauty.

5. rise / descend; day / night; seeds / unborn; fulfilment / wandering; reck'd / unreck'd.

Long-answer questions (4 marks each)

1. Summarise the poem in your own words. [4]
2. What might happen on the earth if it does not rain for a long time? [4]

Model answers

1. The poet asks the soft shower who it is, and the rain answers that it is "the Poem of Earth". It explains that it rises invisibly from land and sea to the sky, changes shape and then comes down again to wash the dry earth and wake the seeds that are waiting to be born. In this way it keeps returning life to its own source. Like a song, which comes from its birthplace, wanders and at last comes back with love, rain is a gift that always returns.

2. If it does not rain for a long time, rivers, ponds and wells will dry up. Crops will fail and there will be drought and famine. Animals and people will lack drinking water and may fall ill. Forests will become dry and catch fire easily. People may have to leave their land and migrate. This shows how much life on earth depends on rain.

5.3 Grammar and writing tasks of the unit

Grammar I: Zero and first conditional

A conditional sentence has an if-clause (the condition) and a main clause (the result). When the if-clause comes first, put a comma after it.

Type	Use	If-clause	Main clause	Example
Zero	general truths, science	if + present simple	present simple	If you heat water, it boils.
First	real, likely future	if + present simple	will / can / may + base verb	If it is cold, I will wear a coat.

Other words that work like if

Word	Meaning	Example
unless	if … not	The horse won't kick you unless you go behind it.
provided (that) / providing	only if	Provided that you consent, I will take leave.
as long as	only if	As long as they communicate well, the problem may be solved.
in case	because it may happen	Take an umbrella in case it rains.

Exercise A — Complete with the correct form

1. If it is cold, I ____ (wear) a coat.
2. If Purna helps with the housework, his mother ____ (have) more time for him.
3. You ____ (save) petrol if you drove more carefully. (second conditional — look carefully)
4. Say "hello" if you ____ (see) her.
5. Provided that you ____ (consent), I will take a few days' leave next week.
6. What happens if you ____ (heat) water?
7. Take care of the pence and the pounds ____ (take) care of themselves.

Exercise B — Match the halves

(a) If you go to Taplejung, (b) You will get well soon (c) The horse won't kick you (d) What happens (e) As long as they communicate well,

(i) if you follow the doctor's advice. (ii) unless you go behind it. (iii) you can see the Pathibhara temple. (iv) if you heat water? (v) the problem might be solved.

Grammar II: Second and third conditional

Type	Use	If-clause	Main clause	Example
Second	unreal, imaginary or unlikely present/future	if + past simple (were for all persons)	would / could / might + base verb	If I were a bird, I would see the land below.
Third	unreal past: things that did not happen	if + past perfect	would / could / might + have + past participle	If he had not come to Nepal, he would not have seen Mt Everest.

Formal inverted forms (leave out if and put the verb first):

Normal	Inverted
If you had arrived earlier, you would have seen Manashi.	Had you arrived earlier, you would have seen Manashi.
If Rijisa were in the USA, she would be working for a company.	Were Rijisa in the USA, she would be working for a company.
If he were to see me, he would know me at once.	(were to shows an unlikely future)

Exercise C — Complete with the correct form of the verb

1. If Gaurab were the captain, the team ____ (play) better.
2. I ____ (call) you had I known you were in Nepal.
3. If he ____ (not come) to Nepal, he would not have seen Mt Everest.
4. Had you arrived a bit earlier, you ____ (see) Manashi.
5. We could slow down global warming if we ____ (reduce) energy consumption.
6. Were Rijisa in the USA, she ____ (be) working for a company.
7. How would you feel if someone ____ (ask) you for an autograph?
8. What ____ (you / do) if Keshab had proposed to you? (past)
9. If I ____ (have) a life jacket, I could certainly swim across the river.

Exercise D — Complete the sentences with your own clauses

1. If you don't leave soon, ____.
2. If it rains in winter, ____.
3. I will help you as long as ____.
4. A country cannot develop unless ____.
5. What will you do if ____?

Suggested answers

1. you will miss the bus.

2. the roads will be slippery.

3. you tell the truth.

4. it invests in education.

5. they insult you.

Writing I: Instructions

Instructions tell the reader how to do something in order. Features: a title (How to…); a list of materials; numbered steps; imperative verbs in the correct order; sequence words (first, next, then, after that, finally); short sentences.

Writing II: A letter to the editor

A letter to the editor is a formal letter addressed to a newspaper. The writer gives an address and date, addresses The Editor, writes a subject line, states the problem, gives its causes and effects with evidence, suggests solutions and thanks the editor. A complaint should be polite, factual and constructive.

Task. Write a letter of complaint about unmanaged garbage in your locality. Mention the hazards to health and suggest measures.

Chapter summary

• Yes, You Can Boil Water at Room Temperature: water boils when vapour pressure equals external pressure; lower pressure (altitude, a vacuum, a pulled syringe plunger) means a lower boiling point.
• Key words: altitude, molecule, equilibrium, condense, factoid, vacuum, plunger.
• The Voice of the Rain (Walt Whitman, free verse): the rain says it is "the Poem of Earth"; it rises, changes form, descends, revives seeds and returns, like a song.
• Devices: personification, metaphor, free verse, antithesis.
• Conditionals: zero (if + present, present); first (if + present, will); second (if + past, would); third (if + past perfect, would have + pp). Unless = if not; provided that / as long as = only if. No will in the if-clause.
• Instructions: title, materials, numbered imperative steps, sequence words. A letter to the editor: address, date, subject, problem, causes and effects, solutions, thanks.

Practice questions

Objective questions (1 mark each)

1. Water boils at a lower temperature on a mountain because [1]athe air pressure is lowerbthe sun is hottercwater is purerdthe wind is stronger
2. "Lave" in the poem means [1]ato washbto burncto drydto lift
3. "If I ____ rich, I would build a school." [1]aambwas beingcweredwill be
4. "Unless you work hard, you will fail" means [1]aIf you work hard, you will failbIf you don't work hard, you will failcYou never workdYou will pass

Answers

1. (a).

2. (a).

3. (c).

4. (b).

Short answer questions (2 marks each)

1. What is a vacuum? [2]
2. How does the poet suggest that rain is a cycle? [2]
3. Rewrite using the third conditional: "I did not know the answer, so I did not tell you." [2]
4. Rewrite in inverted form: "If he had studied, he would have passed." [2]

Answers

1. A space or container from which the air has been removed.

2. The rain says that it rises from earth to heaven and descends again to give life and then returns to its origin.

3. If I had known the answer, I would have told you.

4. Had he studied, he would have passed.

Long answer questions (4 marks each)

1. Write instructions on "How to make a cup of tea". [4]
2. Write a letter to the editor about the shortage of drinking water in your locality. [4]

Answers

1. Outline: title; materials (water, tea leaves, milk, sugar, pan, strainer, cup); numbered steps — boil water, add tea, add milk and sugar, boil again, strain, serve; use first, then, after that, finally.

2. Outline: address and date; The Editor; subject (Shortage of drinking water in Dhankuta-6); problem and since when; effects (women and children walking far, illness, absence from school); causes (leaking pipes, poor distribution); suggestions (repair pipes, extra tanker supply, rainwater harvesting); polite close.