The candle and what burning is

Tests: 4 of 10 right · Exam: 0 of 4 right · Kind: ★★★ · Understood: 7 of 14 · Run: 2026-10-18, commit f3c23ea72

Lesson 11 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 ✗

Your friend blows out a candle, a grown-up brings a match to the smoke, and the candle relights. Why?

1. The candle was never really out — ← Mova's choice · score 2
2. Smoke is made of pure oxygen, which bursts into flame — no support
3. The smoke still holds wax gas, which catches fire — ✓ the right answer · no support
4. The match touched the wick by accident — no support

Why: It took the question to ask why something happens (its cause). It chose option 1 with score 2, the only option with support. Its support: lesson 11, line 6: «In a candle it is the wax gas that burns, not the solid wax or the string; a freshly blown-out candle can relight through its smoke.», reached through the option's own match among the sentences about the question's things. What matched: the same doer «blown out candle» (+1); the same property (+1). The right option, 3, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 2 · ★★★ · right ✓

The class video says: "The water rises in the jar because exactly the oxygen is used up." What is missing?

1. Nothing, that is the whole story and nothing else happens in the jar — no support
2. The jar gets lighter and floats — no support
3. The water is sucked up by the wick — no support
4. The air also cools and shrinks after the flame goes out — ← Mova's choice · ✓ the right answer · score 5

Why: It took the question to ask which statement is true. It chose option 4 with score 5, the only option with support. Its support: lesson 11, line 10: «The water that rises in a jar over a candle in water is not only because oxygen is used up; the air in the jar also cools and shrinks.», reached through the same lesson line as the sentence the question matched. What matched: the same action «shrink» (+3); the same doer «air» (+2). · the question and its options parsed, with trees and pragmatics

Test 3 · ★★★ · right ✓

"why don't gas hobs leave black crap on pans but candles do on plates" Best answer?

1. Gas hobs are wiped clean by tiny robots — no support
2. Gas mixed with air burns cleanly with no soot — ← Mova's choice · ✓ the right answer · score 3
3. Pans are too hot for soot — no support
4. Candle wax is black inside — no support

Why: It took the question to ask why something happens (its cause). It chose option 2 with score 3, the only option with support. Its support: lesson 11, line 6: «In a candle it is the wax gas that burns, not the solid wax or the string; a freshly blown-out candle can relight through its smoke.», reached through the same lesson line as the sentence the question matched. What matched: the same action «burn» (+2); the same doer «wax gas» (+1). · the question and its options parsed, with trees and pragmatics

Test 4 · ★★★ · wrong ✗

Why are you warm?

1. Your clothes make heat — ← Mova's choice · no support
2. Your body slowly burns food with oxygen, giving out heat — ✓ the right answer · no support
3. Your blood is heated by the Sun every day, even through the clouds — no support
4. Your bones are always hot — 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

Test 5 · ★★★ · right ✓

In a cartoon, a camper brings a glowing barbecue into the tent "to keep warm". What's wrong?

1. The tent would get too cold — no support
2. The charcoal would go out at once — no support
3. Charcoal gives off carbon monoxide, which can kill silently — ← Mova's choice · ✓ the right answer · score 6
4. Nothing, it is a great way to stay warm on a cold night in the woods — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 6, the only option with support. Its support: lesson 11, line 17: «Burning charcoal gives off carbon monoxide, an invisible poisonous gas, so barbecues must never be brought indoors or into a tent.», reached through a sentence linked to the one the question matched. What matched: the same action «give off» (+2); the same doer «burning charcoal» (+2); the same thing acted on «carbon monoxide» (+2). · the question and its options parsed, with trees and pragmatics

Test 6 · ★★★ · wrong ✗

Your brother says a candle gets shorter because the wax "just melts and drips". What is the truth?

1. All of it melts and drips down onto the table, where you can scrape it off — no support
2. It sinks into the wick — ← Mova's choice · score 2
3. It turns back into a solid inside — no support
4. Most of the wax burns into carbon dioxide and water vapour — ✓ the right answer · no support

Why: It took the question to ask which statement is true. It chose option 2 with score 2, the only option with support. Its support: lesson 7, line 13: «In a lava lamp, wax heated at the bottom expands, becomes less dense and rises, then cools and sinks.», reached through the option's own match among the sentences about the question's things. What matched: the same action «sink» (+1); the same doer «wax» (+1). The right option, 4, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 7 · ★★★ · right ✓

What would happen to a candle under a very small jar?

1. It would go out very quickly — ← Mova's choice · ✓ the right answer · score 3
2. It would burn on forever and ever — no support
3. It would turn blue and stay lit — no support
4. It would grow taller and brighter — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 3, the only option with support. Its support: lesson 11, line 9: «A jar over a candle makes the flame go out because it runs out of oxygen; a bigger jar holds more air, so the candle lasts longer.», reached through the option's own match among the sentences about the question's things. What matched: the same action «go out» (+1); the same doer «jar» (+1); the same property (+1). · the question and its options parsed, with trees and pragmatics

Test 8 · ★★★ · wrong ✗

"steel wool burns but my spoon doesn't, they're both steel, wtf" Best answer?

1. Spoons are fireproof plastic — ← Mova's choice · no support
2. Steel wool is not made of metal at all, it is a kind of sheep's wool — no support
3. Thin threads have lots of surface for oxygen to reach — ✓ the right answer · no support
4. Only spoons are coated with ice — 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 ✗

A grown-up holds a cold spoon high above a candle and drops of water appear. Where do they come from?

1. They leak out through the metal of the spoon — ← Mova's choice · no support
2. They come out of the cotton wick as it burns — no support
3. They are drops of dew from the night air — no support
4. They are made by the burning of the wax — ✓ 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 10 · ★★★ · wrong ✗

Your little cousin asks how a trick candle "knows" to relight. Best answer?

1. It is magic — ← Mova's choice · no support
2. It listens for clapping — no support
3. It has a tiny brain in the wax that tells it when the party is not over — no support
4. It doesn't know; hot metal powder in the wick catches fire again — ✓ 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

Exam question 1 · formal language · wrong ✗

Which of the following statements most accurately characterises the combustion of a candle?

1. The vaporised wax combines with oxygen, yielding carbon dioxide and water vapour — ✓ the right answer · no support
2. The flame destroys the atoms of the wax — ← Mova's choice · score 5
3. The solid wax combines directly with nitrogen — score 4
4. The cotton wick alone is consumed, the wax remaining wholly intact and merely dripping — score 4

Why: It took the question to ask who or what does it. It chose option 2 with score 5, against 4 for the next best. Its support: lesson 11, line 1: «A candle looks simple, but it is a little chemistry factory: the flame melts the wax, the liquid wax climbs the wick, turns into gas, and the gas is what actua…», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+3); the same doer «gas» (+2). The right option, 1, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · wrong ✗

Identify the principal reason for which a candle enclosed beneath a jar is extinguished.

1. The wax is exhausted at the moment of enclosure, the jar drawing it upward — ← Mova's choice · no support
2. Light cannot pass through the jar — no support
3. The supply of oxygen within the jar is insufficient to sustain combustion — ✓ the right answer · no support
4. The glass of the jar absorbs the heat of the flame — 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 3 · formal language · wrong ✗

Select the response that is consistent with the established facts concerning respiration and combustion.

1. Respiration produces oxygen, whereas combustion consumes it entirely — ← Mova's choice · no support
2. Respiration requires an open flame within the body — no support
3. Both combine carbon-based substances with oxygen, liberating energy — ✓ the right answer · no support
4. Combustion requires no oxygen whatsoever — 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 4 · formal language · wrong ✗

It is given that a charcoal barbecue has been introduced into an enclosed tent. Ascertain the principal hazard.

1. The cooling of the air within the tent — ← Mova's choice · no support
2. The production of excessive quantities of oxygen — no support
3. The excessive brightness of the glowing charcoal — no support
4. The accumulation of carbon monoxide, a colourless poisonous gas — ✓ 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

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/chemistry/11-the-candle-and-burning/