Water: the most amazing liquid

Tests: 5 of 11 right · Exam: 1 of 4 right · Kind: ★★★ · Understood: 12 of 15 · Run: 2026-10-18, commit f3c23ea72

Lesson 34 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 · ★★★ · wrong ✗

Josh: "ice floats cos it's got air in it, that's all". What's the real reason?

1. Ice is made of lighter water from clouds — ← Mova's choice · score 6
2. He's right, only air bubbles do it — no support
3. Ice is pulled up to the top by the cold — no support
4. Water spreads out when it freezes — ✓ the right answer · score 4

Why: It took the question to ask what it is done to. It chose option 1 with score 6, against 4 for the next best. Its support: lesson 5, line 1: «Water can be ice, liquid water or invisible water vapour, and it moves between these states when it is heated or cooled.», reached through the option's own match among the sentences about the question's things. What matched: it fills the role the question asks for (+3); the same thing acted on «ice» (+2); the same circumstance (+2). Against it: a different doer (counts against) (-1). The right option, 4, scored 4. · the question and its options parsed, with trees and pragmatics

Test 2 · ★★★ · wrong ✗

If ice sank, what might happen to ponds in a cold winter?

1. Fish would be much warmer than they are now — no support
2. Ponds would never freeze at all in winter — score -1
3. Ice would float to the bottom faster — ← Mova's choice · score 3
4. They could freeze from the bottom up — ✓ the right answer · no support

Why: It took the question to ask which statement is true. It chose option 3 with score 3, against -1 for the next best. Its support: lesson 34, line 3: «Most solids sink in their own liquid, but ice floats in your drink. When water freezes its molecules spread out into an open pattern, so ice is lighter than th…», reached through the remembered sentence the question matched. What matched: the same action «float» (+2); the same doer «ice» (+1). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 3 · ★★★ · right ✓

Stranded on a raft in a film, the hero drinks seawater "to stay alive". What's true?

1. Seawater is better than rain water — no support
2. Seawater would make him thirstier — ← Mova's choice · ✓ the right answer · score 4
3. Seawater is fine if you're thirsty — no support
4. Seawater is safe once it is cold enough — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 4, the only option with support. Its support: lesson 34, line 10: «Drinking seawater makes you more thirsty, because the body needs extra water to get rid of the salt.», reached through the same lesson line as the sentence the question matched. What matched: the same action «make» (+4); the same property (+1). Against it: a different thing acted on (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 4 · ★★★ · wrong ✗

"just boil the sea water then, sorted". Why doesn't that make it drinkable?

1. Boiling makes it into tap water — ← Mova's choice · score 4
2. Boiling makes the salt float away — score 2
3. Boiling kills germs but leaves the salt — ✓ the right answer · score 2
4. Boiling turns all of the salt into sugar instead — no support

Why: It took the question to ask why something happens (its cause). It chose option 1 with score 4, against 2 for the next best. Its support: lesson 15, line 7: «Vinegar is water with acetic acid in it, made by bacteria from wine or cider.», reached through the option's own match among the sentences about the question's things. What matched: the same action «make» (+2); the same thing acted on «water» (+2). The right option, 3, scored 2. · the question and its options parsed, with trees and pragmatics

Test 5 · ★★★ · right ✓

Gran says limescale in the kettle means the water is dirty. What's true?

1. It is minerals from rocks, not dirt — ← Mova's choice · ✓ the right answer · score 6
2. It is soap someone left in the water — no support
3. It is germs in the pipes that turned white — score 4
4. She's right, it is dirt and mud from old pipes — score 4

Why: It took the question to ask which statement is true. It chose option 1 with score 6, against 4 for the next best. Its support: lesson 34, line 14: «Hard water has minerals dissolved from chalk and limestone rocks; when it is heated the minerals come out as white limescale on kettles and taps.», reached through the same lesson line as the sentence the question matched. What matched: the same place «chalk» (+4); the same thing acted on «minerals» (+2). · the question and its options parsed, with trees and pragmatics

Test 6 · ★★★ · wrong ✗

You drop washing-up liquid near a floating paperclip and it sinks. Why?

1. Soap pulls the clip down by magnet — ← Mova's choice · no support
2. Soap makes the paperclip heavier — no support
3. Soap makes the water much colder — no support
4. Soap weakens the surface skin — ✓ the right answer · 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 7 · ★★★ · wrong ✗

Pond skater in a cartoon walks on water by magic. What's the real trick?

1. It flaps its tiny wings very fast to hover — ← Mova's choice · no support
2. It stands on the water's surface skin — ✓ the right answer · no support
3. It walks on hidden floating leaves — no support
4. Its feet are full of helium — 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 8 · ★★★ · right ✓

"why're plants not dry at the top, how does the water get up there?"

1. Water climbs up thin tubes, clinging and pulling — ← Mova's choice · ✓ the right answer · score 8
2. The Sun pulls water up by gravity — score 6
3. Roots squirt water up like a hose — no support
4. The plant drinks rain only through leaves — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 8, against 6 for the next best. Its support: lesson 34, line 7: «Water climbs up a paper towel because it clings to the fibres and pulls more water up behind it; plants use this kind of climbing, with other forces, to lift w…», reached through the same lesson line as the sentence the question matched. What matched: the same action «cling» (+4); the same doer «water» (+4). · the question and its options parsed, with trees and pragmatics

Test 9 · ★★★ · right ✓

Someone says "pure water is everywhere in nature". What's true?

1. Yes, rivers are always pure water — no support
2. Only rain is impure in nature — no support
3. Yes, the sea is pure water with fish — score 3
4. Water dissolves things, so nature's water is rarely pure — ← 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 34, line 4: «Water dissolves more things than almost any other liquid, so water in nature is never quite pure: the sea is salty, tap water carries minerals, and that is why…», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «more things» (+2); the same action «dissolve» (+1); the same doer «water» (+1). · the question and its options parsed, with trees and pragmatics

Test 10 · ★★★ · wrong ✗

You run a race in the heat and feel dizzy. Why does drinking water help?

1. Water gives your muscles new sugar — no support
2. Water cools down the air around you — ← Mova's choice · score 4
3. Your body lost water by sweating — ✓ the right answer · score 4
4. Water stops you sweating any more — score 4

Why: It took the question to ask why something happens (its cause). It chose option 2 with score 4, tied with another option at 4 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 34, line 11: «In the water cycle water evaporates, rises, cools and condenses into clouds, then falls as rain; the same water goes round and round, so the water you drink ma…», reached through the option's own match among the sentences about the question's things. What matched: the same action «cool» (+2); the same doer «water» (+2). The right option, 3, scored 4. · the question and its options parsed, with trees and pragmatics

Test 11 · ★★★ · right ✓

If you sealed a jar of water and left it in the sun, why would drops form on the lid?

1. The lid sweats like a person does — no support
2. Water evaporates and condenses on the cooler lid — ← Mova's choice · ✓ the right answer · score 2
3. Rain gets in through the glass — no support
4. The lid melts in the sunshine — no support

Why: It took the question to ask why something happens (its cause). It chose option 2 with score 2, the only option with support. Its support: lesson 34, line 5: «Tap water is cleaned before it reaches you: it is left to settle, filtered, and treated with a little chlorine to kill germs; many places in the world still la…», reached through the cause of the sentence the question matched. What matched: the same doer «water» (+4). Against it: a different action (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Exam question 1 · formal language · right ✓

Identify the principal reason for which ice floats upon liquid water.

1. Liquid water exerts a magnetic force on ice — no support
2. Ice is composed of a lighter variety of water — no support
3. Water expands upon freezing and becomes less dense — ← Mova's choice · ✓ the right answer · score 8
4. Ice contains a large proportion of trapped air — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 8, the only option with support. Its support: lesson 5, line 13: «Water expands when it freezes, so ice floats, ponds freeze from the top down and frozen pipes can burst.», reached through the same lesson line as the sentence the question matched. What matched: the same action «expand» (+4); the same doer «water» (+4). · 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 effect of boiling upon drinking water?

1. All dissolved salts are removed entirely — no support
2. All chemical contaminants are eliminated — no support
3. The water is converted into a different substance — ← Mova's choice · score 3
4. Most germs are destroyed, but dissolved salt remains — ✓ the right answer · no support

Why: It took the question to ask who or what does it. It chose option 3 with score 3, the only option with support. Its support: lesson 34, line 7: «Water climbs up a paper towel because it clings to the fibres and pulls more water up behind it; plants use this kind of climbing, with other forces, to lift w…», reached through the option's own match among the sentences about the question's things. What matched: the same thing acted on «more water» (+2); the same place «water» (+2). Against it: a different action (counts against) (-1). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · wrong ✗

It is given that hard water is heated in a kettle. Select the observation consistent with the established facts.

1. The water ceases to boil entirely and remains cold — ← Mova's choice · score 2
2. The kettle becomes magnetic — no support
3. The water turns a pale blue in colour — score 2
4. A white deposit of limescale accumulates — ✓ the right answer · no support

Why: It took the question to ask which statement is true. It chose option 1 with score 2, tied with another option at 2 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 5, line 16: «Salt makes ice melt below 0 °C, because salty water freezes at a lower temperature; it stops working well in very hard frost.», reached through the option's own match among the sentences about the question's things. What matched: the same action «stop» (+1); the same doer «water» (+1). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · wrong ✗

Ascertain the principal reason for which the ocean is saline.

1. Marine animals secrete salt continuously — ← Mova's choice · no support
2. Salt is deposited from the clouds by rain — no support
3. The ocean floor consists of pure salt — no support
4. Salts carried from rocks by rivers remain when water evaporates — ✓ the right answer · 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

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