Dyes, inks and colouring

Tests: 6 of 11 right · Exam: 3 of 4 right · Kind: plain · Understood: 9 of 15 · Run: 2026-10-18, commit f3c23ea72

Lesson 27 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 ✓

Mia: "jeans fade cos the blue sinks deep inside the threads". What's true?

1. The blue sits on the outside and rubs off — ← Mova's choice · ✓ the right answer · score 6
2. The jeans dry out and lose colour — no support
3. The blue is eaten by the soap — no support
4. She's right, it sinks to the middle of each thread — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 6, the only option with support. Its support: lesson 27, line 12: «Jeans are dyed with indigo, which sits mostly on the outside of the threads, so each wash rubs a little off and the jeans fade.», reached through the same lesson line as the sentence the question matched. What matched: the same action «sit» (+4); the same place «outside» (+2). · the question and its options parsed, with trees and pragmatics

Test 2 · wrong ✗

Dad, holding a pink shirt: "who put a bloody red sock in with the whites?" What happened?

1. Loose red dye moved onto the white shirt — ✓ the right answer · no support
2. The hot water turned the white shirt red all over — no support
3. The shirt soaked up red light — no support
4. The machine was painted inside — ← Mova's choice · score 4

Why: It took the question to ask who or what does it. It chose option 4 with score 4, the only option with support. Its support: lesson 16, line 3: «Dad takes an antacid tablet for heartburn: the alkali in it cancels some stomach acid and the burning eases. Gardeners spread lime, an alkali, on sour soil for…», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+4); the same doer «dad» (+2). Against it: a different action (counts against) (-2). The right option, 1, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 3 · right ✓

If you hung your favourite poster in a sunny window for a year, what would happen?

1. Its colours would fade — ← Mova's choice · ✓ the right answer · no support
2. Its colours would get brighter — no support
3. Nothing at all would change — no support
4. It would turn completely black — 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 4 · right ✓

A cartoon king wears purple because "purple was the cheapest dye". What's wrong?

1. Purple dye was rare and very dear — ← Mova's choice · ✓ the right answer · no support
2. Purple was made from onions — no support
3. Kings only ever wore gold — no support
4. Purple was banned for kings by the law — 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 5 · wrong ✗

"pigment and dye are the same thing, just colour, innit". What's the difference?

1. There is no difference at all — no support
2. A dye is natural, a pigment is not — no support
3. A dye dissolves and soaks in, a pigment sits on top — ✓ the right answer · score 7
4. A pigment is liquid, a dye is a powder — ← Mova's choice · score 8

Why: It took the question to ask what it is done to. It chose option 4 with score 8, against 7 for the next best. Its support: lesson 27, line 2: «Dyes dissolve and soak into things like cloth, paper or hair. Pigments are coloured powders that do not dissolve; they are mixed with a sort of glue and sit on…», reached through the same lesson line as the sentence the question matched. What matched: it fills the role the question asks for (+5); the same thing acted on «coloured powders» (+4). Against it: a different doer (counts against) (-1). The right option, 3, scored 7. · the question and its options parsed, with trees and pragmatics

Test 6 · right ✓

You colour with a black felt-tip and drip water on it, and other colours appear. Why?

1. Water makes new colours out of nothing — no support
2. Water turns black ink into rainbow ink — no support
3. The paper had hidden colours inside — no support
4. Black felt-tip ink is a mix of colours — ← Mova's choice · ✓ the right answer · score 3

Why: It took the question to ask why something happens (its cause). It chose option 4 with score 3, the only option with support. Its support: lesson 27, line 6: «Fresh stains come out more easily than old ones, because the colour has had less time to hold on to the fibres.», reached through the cause of the sentence the question matched. What matched: the same circumstance (+4). Against it: a different doer (counts against) (-1). · the question and its options parsed, with trees and pragmatics

Test 7 · wrong ✗

Ella's aunt dyes her hair at home without reading the box. What should she have done first?

1. Leave the dye in the sun — ← Mova's choice · no support
2. A skin test for allergy — ✓ the right answer · no support
3. Wash the dye in cold water — no support
4. Mix two dyes together — 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 ✓

Ben says food colouring makes red icing taste of strawberries. What's true?

1. Colouring makes icing sour — no support
2. He's right, red always tastes of strawberry — no support
3. Colouring adds looks, not taste — ← Mova's choice · ✓ the right answer · score 12
4. Colouring makes icing taste of beetroot — score 7

Why: It took the question to ask which statement is true. It chose option 3 with score 12, against 7 for the next best. Its support: lesson 27, line 15: «Food colourings are tested to be safe in small amounts; they add looks, not taste, and some come from plants such as beetroot.», reached through the remembered sentence the question matched. What matched: the same thing acted on «looks» (+5); the same action «add» (+4); the same doer «colourings» (+3). · the question and its options parsed, with trees and pragmatics

Test 9 · right ✓

Which is a natural dye?

1. Perkin's purple from 1856 — no support
2. Onion skins boiled in water — ← Mova's choice · ✓ the right answer · score 8
3. Indigo from a factory — no support
4. Ink from a felt-tip pen — no support

Why: It took the question to ask which statement is true. It chose option 2 with score 8, the only option with support. Its support: lesson 27, line 10: «Onion skins boiled in water release a natural dye that colours eggs brown or golden.», reached through the same lesson line as the sentence the question matched. What matched: the same action «boil» (+4); the same thing acted on «onion skins» (+2); the same circumstance (+2). · the question and its options parsed, with trees and pragmatics

Test 10 · wrong ✗

What would happen if Perkin hadn't had his lucky accident?

1. Snails would have died out — ← Mova's choice · no support
2. Kings would have worn green instead — no support
3. Nobody would ever be able to see purple again — no support
4. Cheap factory purple would have come later — ✓ 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 11 · wrong ✗

"spilt blueberry smoothie on me top, I'll wash it next week". Good plan?

1. Yes, old stains come out easier — ← Mova's choice · no support
2. No, it should be put in the sun first — no support
3. Yes, the stain will fade by itself — no support
4. No, fresh stains wash out more easily — ✓ 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 · right ✓

Which of the following statements most accurately characterises the distinction between a dye and a pigment?

1. A dye is a solid, whereas a pigment is a gas — score 6
2. A dye dissolves and is absorbed, whereas a pigment is insoluble and remains on the surface — ← Mova's choice · ✓ the right answer · score 8
3. A dye is invariably natural, whereas a pigment is invariably synthetic — score 6
4. There exists no distinction between them — no support

Why: It took the question to ask who or what does it. It chose option 2 with score 8, against 6 for the next best. Its support: lesson 27, line 17: «A red sock can leak loose dye into the wash water, and the dye then sticks to other clothes; colour-catcher sheets soak up loose dye.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+4); the same action «stick» (+2); the same doer «dye» (+2). · the question and its options parsed, with trees and pragmatics

Exam question 2 · formal language · wrong ✗

Identify the principal cause of the fading of textiles exposed to sunlight.

1. The absorption of colour by window glass — ← Mova's choice · no support
2. The evaporation of the fibres in warm air — no support
3. The decomposition of dye molecules by ultraviolet radiation — ✓ the right answer · no support
4. The bleaching action of moisture alone — 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 · right ✓

It is given that William Perkin, in 1856, produced a purple dye. Select the statement consistent with the established facts.

1. The discovery was accidental, during an attempt to make a medicine — ← Mova's choice · ✓ the right answer · score 3
2. The dye was obtained from onion skins — no support
3. The dye was extracted from sea snails — no support
4. The discovery was made at an advanced age — 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 27, line 9: «In 1856 William Perkin, aged 18, was trying to make a medicine and made the first cheap factory-made purple dye by accident.», reached through the same lesson line as the sentence the question matched. What matched: the same action «make» (+4); the same thing acted on «medicine» (+2). Against it: one says «not», the other does not (counts against) (-3). · the question and its options parsed, with trees and pragmatics

Exam question 4 · formal language · right ✓

Ascertain the reason for which a white garment acquires a pink colour when laundered with a red sock.

1. Loose dye is released into the water and attaches to the garment — ← Mova's choice · ✓ the right answer · score 7
2. The temperature of the water converts white to pink — no support
3. The garment reflects the colour of the sock — no support
4. The detergent contains a red pigment — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 7, the only option with support. Its support: lesson 27, line 17: «A red sock can leak loose dye into the wash water, and the dye then sticks to other clothes; colour-catcher sheets soak up loose dye.», reached through the remembered sentence the question matched. What matched: the same thing acted on «loose dye» (+5); the same place «wash water» (+4). Against it: a different action (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/27-dyes-inks-colouring/