Sound — vibrations, loudness, pitch and echoes

Tests: 5 of 12 right · Exam: 2 of 4 right · Kind: plain · Understood: 7 of 16 · Run: 2026-10-18, commit f3c23ea72

Lesson 54 of the world 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 ✗

You press your ear to a long wooden table while a friend taps the far end. What do you notice?

1. You hear nothing, since wood blocks all sound — ← Mova's choice · no support
2. You hear the tap clearly through the wood — ✓ the right answer · no support
3. You hear it only after a long delay — no support
4. You hear the tap as a high whistle — 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 2 · right ✓

A ruler is held at the edge of a desk and twanged. The overhanging part is made shorter. What happens?

1. The note becomes higher — ← Mova's choice · ✓ the right answer · no support
2. The ruler makes no sound — no support
3. The note stays the same — no support
4. The note becomes lower — 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 ✗

Which is true about loudness?

1. Loud sounds always have a high pitch — ← Mova's choice · no support
2. Bigger vibrations make louder sounds — ✓ the right answer · no support
3. Faster vibrations make louder sounds — no support
4. Loudness depends only on the colour of the object — 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 4 · right ✓

A shout from the bottom of a canyon is heard again a moment later. Why?

1. The sound bounced off the rock walls — ← Mova's choice · ✓ the right answer · no support
2. Another person copied the shout — no support
3. Sound stops and starts again in canyons — no support
4. The canyon made its own sound — 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 ✗

Why does a gym with bare walls sound more echoey than a classroom with posters, carpets and curtains?

1. The gym has more air in it — no support
2. Soft things in the classroom absorb sound — ✓ the right answer · no support
3. Posters make sounds louder — ← Mova's choice · score 4
4. The classroom has no sound waves — no support

Why: It took the question to ask why something happens (its cause). It chose option 3 with score 4, the only option with support. Its support: lesson 54, line 4: «A bigger vibration makes a louder sound; a faster vibration makes a higher sound. A short, tight guitar string vibrates fast and sounds high; a long, loose str…», reached through the same lesson line as the sentence the question matched. What matched: the same action «make» (+3); the same thing acted on «louder sound» (+2); the same property (+1). Against it: a different doer (counts against) (-2). The right option, 2, found no support in what it remembers. · the question and its options parsed, with trees and pragmatics

Test 6 · right ✓

Whales can call to each other across many kilometres of ocean. Which fact helps explain this?

1. Water makes sounds silent — no support
2. Sound travels well through water — ← Mova's choice · ✓ the right answer · score 5
3. Sound needs empty space to travel — score 5
4. Sound cannot travel in water — score 5

Why: It took the question to ask who or what does it. It chose option 2 with score 5, tied with another option at 5 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 54, line 5: «When sound hits a large hard surface, such as a cliff or a wall of an empty hall, it bounces back. The sound we hear coming back is called an echo.», 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 doer «sound» (+3). Against it: a different action (counts against) (-2). · the question and its options parsed, with trees and pragmatics

Test 7 · wrong ✗

A tight elastic band gives a high twang. You loosen it. What happens to the note?

1. It stays exactly the same — ← Mova's choice · no support
2. It becomes higher — no support
3. It becomes lower — ✓ the right answer · no support
4. It becomes louder only — 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 ✓

If there were no air in a room, could you hear a ringing alarm clock in it?

1. No, sound needs something to travel through — ← Mova's choice · ✓ the right answer · score 10
2. Yes, but only more quietly — no support
3. Only if the clock is metal — no support
4. Yes, sound travels best in empty space — score 10

Why: It took the question to ask which statement is true. It chose option 1 with score 10, tied with another option at 10 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 54, line 3: «Sound needs something to travel through: air, water or solids such as wood and metal. In space there is no air, so there is no sound — astronauts talk by radio.», reached through a sentence linked to the one the question matched. What matched: the same action «need» (+3); its «because» matches the remembered cause (+3); the same doer «sound» (+2); the same thing acted on «something» (+2). · the question and its options parsed, with trees and pragmatics

Test 9 · wrong ✗

why's the big drum go boom n the little one go tick

1. The big drum vibrates faster — ← Mova's choice · no support
2. Big drums have no vibrations — no support
3. Slower vibrations of the big drum make lower sounds — ✓ the right answer · no support
4. The small drum is louder inside — 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 10 · wrong ✗

shouted in the empty hall n heard myself back lol why

1. Someone was copying you — ← Mova's choice · no support
2. The floor made its own sound — no support
3. The sound got stuck in the air — no support
4. The sound bounced back from the hard walls as an echo — ✓ the right answer · 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 11 · wrong ✗

my cousin says you can hear explosions in space like in films. true?

1. Yes, sound travels best in space — ← Mova's choice · score 10
2. No, you can only hear them if you are standing on the Moon — no support
3. No, sound cannot travel through empty space — ✓ the right answer · score 5
4. Yes, but only very loud ones — no support

Why: It took the question to ask which statement is true. It chose option 1 with score 10, against 5 for the next best. Its support: lesson 40, line 13: «Sound travels about one kilometre in 3 seconds through air.», reached through the remembered sentence the question matched. What matched: the same action «travel» (+4); the same place «air» (+4); the same doer «sound» (+2). The right option, 3, scored 5. · the question and its options parsed, with trees and pragmatics

Test 12 · right ✓

Ben reckons sound can't go through water. right?

1. No, sound travels through water, even faster than through air — ← Mova's choice · ✓ the right answer · score 12
2. Yes, water stops all sound — no support
3. Yes, fish cannot hear anything — no support
4. No, it travels only through ice — score 6

Why: It took the question to ask which statement is true. It chose option 1 with score 12, against 6 for the next best. Its support: lesson 54, line 8: «Sound travels faster through water and solids than through air.», reached through the remembered sentence the question matched. What matched: the same action «travel» (+4); the same place «water» (+4); the same doer «sound» (+2); the same property (+2). · 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 origin of all sound?

1. All sound is produced by vibrations — ← Mova's choice · ✓ the right answer · no support
2. All sound is produced by the reflection of light — no support
3. All sound is produced by the motion of the wind — no support
4. All sound is produced by the flow of electricity — 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 ✗

Select the response that is consistent with the established facts concerning the propagation of sound through a vacuum.

1. Sound travels most rapidly through a vacuum — score 2
2. Sound travels through a vacuum only at night — score 2
3. Sound travels through a vacuum as readily as through air — ← Mova's choice · score 4
4. Sound is incapable of travelling through a vacuum — ✓ the right answer · score 2

Why: It took the question to ask which statement is true. It chose option 3 with score 4, against 2 for the next best. Its support: lesson 54, line 8: «Sound travels faster through water and solids than through air.», reached through the option's own match among the sentences about the question's things. What matched: the same circumstance (+2); the same action «travel» (+1); the same doer «sound» (+1). The right option, 4, scored 2. · the question and its options parsed, with trees and pragmatics

Exam question 3 · formal language · wrong ✗

It is given that a string is shortened and tightened. Ascertain the consequent alteration in the note produced thereby.

1. The pitch of the note shall be lowered — ← Mova's choice · no support
2. The loudness alone shall be diminished — no support
3. The note shall remain wholly unaltered — no support
4. The pitch of the note shall be raised — ✓ 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 4 · formal language · right ✓

Identify the principal reason for which curtains and carpets reduce echoes within a room.

1. Soft materials reflect sound more strongly than walls — score 5
2. Soft materials raise the pitch of every sound — no support
3. Soft materials absorb sound rather than reflecting it — ← Mova's choice · ✓ the right answer · score 10
4. Soft materials accelerate the passage of sound — no support

Why: It took the question to ask which statement is true. It chose option 3 with score 10, against 5 for the next best. Its support: lesson 54, line 14: «Soft materials such as curtains and carpets absorb sound and reduce echoes.», reached through the same lesson line as the sentence the question matched. What matched: the same action «absorb» (+4); the same doer «soft materials» (+4); the same thing acted on «sound» (+2). · the question and its options parsed, with trees and pragmatics

This page in Markdown → https://md.mova.elamur.ai/free/en/school-run/world/54-sound/