The air we breathe

Tests: 4 of 11 right · Exam: 2 of 4 right · Kind: ★★ · Understood: 10 of 15 · Run: 2026-10-18, commit f3c23ea72

Lesson 33 of the chemistry course of Mova's primary school, as Mova's small model took its tests: it had read this lesson and the ones before it and learned from their exercises. Each test shows the options in the order the student saw them, its choice, the right answer, the score of every option and why it chose. The lesson itself, sentence by sentence with trees and pragmatics: the lesson in the corpora.

Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: the lesson's questions in the corpora.

Test 1 · ★★ · right ✓

Ava: "the glass is empty, there's nothing in it". What's true?

1. She's right, there is nothing at all — no support
2. It is full of air, which takes up space — ← Mova's choice · ✓ the right answer · score 11
3. It is full of water vapour only — score 7
4. It is full of nitrogen only — score 7

Why: It took the question to ask which statement is true. It chose option 2 with score 11, against 7 for the next best. Its support: lesson 33, line 2: «Push an "empty" glass upside down into a bowl of water and the water will not fill it, because the glass is full of air. Old diving bells kept people dry under…», reached through the remembered sentence the question matched. What matched: the same circumstance (+4); the same doer «glass» (+3); the same property (+2); the same light verb (be, have, do, get, go) (+2). · the question and its options parsed, with trees and pragmatics

Test 2 · ★★ · wrong ✗

If crisps were packed with ordinary air instead of nitrogen, what might happen?

1. They would get heavier — ← Mova's choice · no support
2. They would turn into popcorn — no support
3. They might go stale faster — ✓ the right answer · no support
4. They would stay fresh longer — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 3 · ★★ · wrong ✗

"carbon dioxide's such a tiny bit of the air, it can't matter, innit". What's true?

1. It cools the planet down — no support
2. He's right, it changes nothing at all, ever — no support
3. Even a small change traps more heat — ✓ the right answer · score 2
4. It is actually most of the air — ← Mova's choice · score 9

Why: It took the question to ask which statement is true. It chose option 4 with score 9, against 2 for the next best. Its support: lesson 18, line 3: «Carbon dioxide is invisible but heavier than air. It can fill a balloon that will not float, and a grown-up can even "pour" it from a jug over a candle and put…», reached through the remembered sentence the question matched. What matched: the same circumstance (+4); the same doer «carbon dioxide» (+3); the same light verb (be, have, do, get, go) (+2). The right option, 3, scored 2. · the question and its options parsed, with trees and pragmatics

Test 4 · ★★ · wrong ✗

Nan says she bought three houseplants "to clean all the air in the flat". What's true?

1. A few plants do little; opening a window does more — ✓ the right answer · score 6
2. Three plants clean the air of a whole flat — ← Mova's choice · score 7
3. Plants take oxygen out of the air — score 2
4. Plants only clean the air at night — score 7

Why: It took the question to ask which statement is true. It chose option 2 with score 7, tied with another option at 7 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 33, line 15: «A few houseplants do very little to clean the air of a room; opening a window does far more.», reached through the remembered sentence the question matched. What matched: the same thing acted on «air» (+5); the same action «clean» (+4). Against it: a different doer (counts against) (-2). The right option, 1, scored 6. · the question and its options parsed, with trees and pragmatics

Test 5 · ★★ · right ✓

A cartoon climber on Everest says there's no air up there at all. What's true?

1. The air is made of ice up there — score 3
2. There is no air at all above the highest clouds — no support
3. There is more oxygen high up — no support
4. There is air, but each breath has less oxygen — ← Mova's choice · ✓ the right answer · score 4

Why: It took the question to ask which statement is true. It chose option 4 with score 4, against 3 for the next best. Its support: lesson 33, line 9: «High on a mountain the air is thinner, so each breath holds less oxygen; climbers on the highest mountains often carry oxygen tanks.», reached through a sentence linked to the one the question matched. What matched: the same doer «breath» (+2); the same thing acted on «less oxygen» (+2). · the question and its options parsed, with trees and pragmatics

Test 6 · ★★ · right ✓

"all that air on top of me weighs loads? then why don't I get squashed lol"

1. Air only presses on tall people — score 7
2. Air presses from all sides, even from inside — ← Mova's choice · ✓ the right answer · score 11
3. Air weighs nothing at all — no support
4. Your skin is too tough and thick to feel it at all — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 11, against 7 for the next best. Its support: lesson 33, line 8: «Air presses on us from all sides, and the air and liquids inside our bodies press back out, so we do not feel its weight.», reached through the remembered sentence the question matched. What matched: the same action «press» (+4); the same place «sides» (+4); the same doer «air» (+3). · the question and its options parsed, with trees and pragmatics

Test 7 · ★★ · right ✓

"ozone hole's done, we wrecked it forever". What's been reported?

1. It is slowly healing after the 1987 ban — ← Mova's choice · ✓ the right answer · score 4
2. It has disappeared completely — no support
3. It was never real at all — no support
4. It is growing faster than ever — no support

Why: It took the question to ask what it is done to. It chose option 1 with score 4, the only option with support. Its support: lesson 32, line 4: «What is not recycled often goes to landfill, a huge hole where rubbish is buried and slowly rots, giving off a gas called methane.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «huge hole» (+3); the same property (+2). Against it: a different action (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 8 · ★★ · wrong ✗

Why is the air clearer in many cities now than fifty years ago?

1. Fewer trees in the parks — ← Mova's choice · no support
2. Stronger summer sunlight — no support
3. Cleaner cars and fuels — ✓ the right answer · no support
4. More fog rolling in from the sea — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Test 9 · ★★ · wrong ✗

Your hay-fever mate sneezes all spring. "it's the air", he moans. What's in the air?

1. Ozone from the sky — no support
2. Carbon dioxide — ← Mova's choice · score 7
3. Too much nitrogen — no support
4. Pollen from plants — ✓ the right answer · no support

Why: It took the question to ask what it is done to. It chose option 2 with score 7, the only option with support. Its support: lesson 33, line 4: «Air can get dirty with smoke and fumes, and people have changed it: we put holes in the ozone layer and are adding carbon dioxide. Yet when the world agreed to…», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+4); the same thing acted on «carbon dioxide» (+3). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 10 · ★★ · wrong ✗

If all the tiny plants in the sea died, what would happen?

1. About half the new oxygen would stop being made — ✓ the right answer · score -1
2. Only the fish would notice any change — no support
3. More oxygen would be made than before — ← Mova's choice · score 7
4. Nothing, forests make all the oxygen — score 1

Why: It took the question to ask what happens next. It chose option 3 with score 7, against 1 for the next best. Its support: lesson 20, line 15: «Water plants use light to make sugar and give off oxygen, so pondweed makes bubbles in sunlight and stops in the dark.», reached through what followed the sentence the question matched. What matched: the same doer «water plants» (+4); the same thing acted on «oxygen» (+4). Against it: a different action (counts against) (-1). The right option, 1, scored -1. · the question and its options parsed, with trees and pragmatics

Test 11 · ★★ · wrong ✗

In an old diving bell, people kept dry under water. How?

1. Air trapped inside kept the water out — ✓ the right answer · no support
2. The water was frozen solid all around it — no support
3. Magnets pushed the water away from it — ← Mova's choice · score 3
4. The bell was filled with dry sponges — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 3, the only option with support. Its support: lesson 13, line 11: «Paint stops rust by keeping air and water away; once the paint is scratched, rust starts at the scratch and creeps under it.», reached through the remembered sentence the question matched. What matched: the same thing acted on «air» (+5); the same property (+2). Against it: a different action (counts against) (-2); a different doer (counts against) (-2). The right option, 1, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · right ✓

Identify the gas which constitutes the greater part of the atmosphere.

1. Nitrogen — ← Mova's choice · ✓ the right answer · no support
2. Oxygen — no support
3. Carbon dioxide — no support
4. Hydrogen — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · wrong ✗

Which of the following statements most accurately characterises the function of the ozone layer?

1. It retains the oxygen within the atmosphere — ← Mova's choice · no support
2. It produces the blue colour of the sky — no support
3. It absorbs much of the harmful ultraviolet radiation from the Sun — ✓ the right answer · no support
4. It supports the weight of the clouds — no support

Why: Nothing it remembers matched the question, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · wrong ✗

It is given that the combustion of coal, oil and gas releases carbon dioxide. Select the consequence consistent with the established facts.

1. The oxygen content rises markedly — ← Mova's choice · no support
2. Additional heat is retained by the atmosphere — ✓ the right answer · no support
3. The ozone layer is immediately restored — no support
4. The atmosphere becomes cooler — no support

Why: No option found support in what it remembers, so it guessed: it took the first option shown. · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · right ✓

Ascertain the reason for which mountaineers at very high altitude frequently carry oxygen.

1. The air at altitude is entirely absent — no support
2. Each breath contains less oxygen in the thinner air — ← Mova's choice · ✓ the right answer · score 7
3. The air at altitude is poisonous — no support
4. Oxygen freezes at high altitude — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 7, the only option with support. Its support: lesson 2, line 19: «Iron in red blood cells helps carry oxygen around the body; meat, beans and lentils are good sources, and spinach is not as iron-rich as the old story says.», reached through the remembered sentence the question matched. What matched: the same thing acted on «oxygen» (+5); the same action «carry» (+4). Against it: a different doer (counts against) (-2). · the question and its options parsed, with trees and pragmatics

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/chemistry/33-the-air-we-breathe/