---
title: Floating and sinking: the push of the water — how Mova does on the tests · Physics
description: Lesson 11 of the physics course of Mova's primary school: 8 of 11 tests right, exam 2 of 4, every question with the options, the student's choice, the right answer and why it chose.
---

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# Floating and sinking: the push of the water

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**Tests:** 8 of 11 right · **Exam:** 2 of 4 right · **Kind:** plain · **Understood:** 10 of 15 · **Run:** 2026-10-18, commit `f3c23ea72`

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Lesson 11 of the physics 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](https://md.mova.elamur.ai/free/en/corpora/school/physics/11-floating-and-sinking/).

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Every question of this lesson and each of its options parsed by Mova, with trees and pragmatics: [the lesson's questions in the corpora](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/).

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### Test 1 · right ✓ {#t1}

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Lily's mum says steel always sinks, so how come ships float?

- **1.** Ships float on their engines — score 8
- **2.** Sea water holds up all metal — no support
- **3.** A ship is hollow and full of air — **← Mova's choice** · **✓ the right answer** · score 12
- **4.** Ships are made of light wood under the paint — no support

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**Why:** It took the question to ask what something is like. It chose option 3 with score 12, against 8 for the next best. Its support: lesson 11, line 3: «Something floats if it is lighter than the same size of water: wood floats, a stone sinks, and a hollow steel ship floats because it is mostly air inside.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+6); the same doer «hollow steel ship» (+4); the same property (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t1/)

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### Test 2 · right ✓ {#t2}

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In the Dead Sea, what can people do?

- **1.** Sink straight down to the bottom like a stone — no support
- **2.** Breathe under the water — no support
- **3.** Walk on the water — no support
- **4.** Float sitting up, reading a newspaper — **← Mova's choice** · **✓ the right answer** · score 10

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**Why:** It took the question to ask what is done. It chose option 4 with score 10, the only option with support. Its support: lesson 11, line 5: «Salty water pushes up harder than fresh water, which is why you float more easily in the sea.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+6); the same action «float» (+4). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t2/)

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### Test 3 · right ✓ {#t3}

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An egg sinks in your glass. You stir in lots of salt. What happens?

- **1.** It sinks faster — score 4
- **2.** It floats — **← Mova's choice** · **✓ the right answer** · score 9
- **3.** It cracks — score 4
- **4.** It dissolves — score 2

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**Why:** It took the question to ask what happens next. It chose option 2 with score 9, against 4 for the next best. Its support: lesson 11, line 15: «An egg sinks in tap water but floats when lots of salt is stirred in, and a rotten egg floats even in fresh water because gas has built up inside.», reached through what followed the sentence the question matched. What matched: the same action «float» (+5); the same doer «egg» (+4). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t3/)

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### Test 4 · right ✓ {#t4}

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lol my brother is all muscle and he sinks like a brick in the pool, why

- **1.** He breathes in too much — no support
- **2.** Muscle sinks more than fat — **← Mova's choice** · **✓ the right answer** · score 5
- **3.** Muscle is full of air — no support
- **4.** Pools are saltier for some people — no support

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**Why:** It took the question to ask which statement is true. It chose option 2 with score 5, the only option with support. Its support: lesson 11, line 17: «Muscle sinks more than fat, so very sporty people may float less well.», reached through the remembered sentence the question matched. What matched: the same action «sink» (+3); the same doer «muscle» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t4/)

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### Test 5 · right ✓ {#t5}

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What would happen if you breathed all the air out while floating?

- **1.** You would shoot straight up out of the water — score 1
- **2.** Nothing at all would change — no support
- **3.** You would sink a little — **← Mova's choice** · **✓ the right answer** · score 4
- **4.** You would float even higher than before — score 4

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**Why:** It took the question to ask what happens next. It chose option 3 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 11, line 16: «You float best lying back with your lungs full of air, and breathing out makes you sink a little.», reached through the same lesson line as the sentence the question matched. What matched: the same action «sink» (+2); the same thing acted on «little» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t5/)

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### Test 6 · wrong ✗ {#t6}

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You put marbles one by one into a clay boat. What happens at last?

- **1.** It floats higher and higher in the water — **← Mova's choice** · no support
- **2.** It turns into a ball — no support
- **3.** The marbles float out — no support
- **4.** It sinks once it gets too heavy — **✓ the right answer** · no support

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**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](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t6/)

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### Test 7 · right ✓ {#t7}

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In a cartoon a man grabs a big stone and floats across the river on it. What is wrong?

- **1.** A stone is heavier than the same size of water, so it sinks — **← Mova's choice** · **✓ the right answer** · score 6
- **2.** Nothing, stones float well — score 2
- **3.** Stones float in rivers but not the sea — no support
- **4.** The stone would fly up — no support

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**Why:** It took the question to ask which statement is true. It chose option 1 with score 6, against 2 for the next best. Its support: lesson 11, line 7: «Things float if they are lighter than the same size of water; wood is light for its size and stone is heavy for its size.», reached through the same lesson line as the sentence the question matched. What matched: the same doer «stone» (+2); the same circumstance (+2); the same property (+1); the same light verb (be, have, do, get, go) (+1). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t7/)

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### Test 8 · wrong ✗ {#t8}

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You hold a beach ball under water and let go. What does it do?

- **1.** It sinks to the bottom — **← Mova's choice** · score 14
- **2.** It stays where it is — no support
- **3.** It shoots back up — **✓ the right answer** · score 14
- **4.** It floats off sideways — no support

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**Why:** It took the question to ask what is done. It chose option 1 with score 14, tied with another option at 14 (the first shown, or the one claiming less beyond what it knows, wins). Its support: lesson 11, line 4: «Shape matters too: a ball of clay sinks, but the same clay pressed into a little boat moves aside much more water and floats.», reached through the remembered sentence the question matched. What matched: it fills the role the question asks for (+6); the same action «sink» (+4); the same doer «ball» (+4). The right option, 3, scored 14. · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t8/)

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### Test 9 · right ✓ {#t9}

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Why does a life jacket help even someone who cannot swim?

- **1.** It teaches you how to swim as you go along — no support
- **2.** It makes the water shallower — no support
- **3.** It makes you lighter than air — no support
- **4.** It turns you face up and keeps you afloat — **← Mova's choice** · **✓ the right answer** · score 2

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**Why:** It took the question to ask why something happens (its cause). It chose option 4 with score 2, the only option with support. Its support: lesson 7, line 11: «Running a metal jar lid under hot water also helps, because the metal grows a little.», reached through the cause of the sentence the question matched. What matched: the same action «grow» (+4). Against it: a different thing acted on (counts against) (-2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t9/)

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### Test 10 · wrong ✗ {#t10}

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Which floats?

- **1.** A coin — **← Mova's choice** · no support
- **2.** A marble — no support
- **3.** A key — no support
- **4.** A cork — **✓ the right answer** · no support

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**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](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t10/)

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### Test 11 · right ✓ {#t11}

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Your bath is full to the brim. What happens when you get in?

- **1.** Water spills over the side — **← Mova's choice** · **✓ the right answer** · no support
- **2.** Nothing at all — no support
- **3.** The water gets hotter — no support
- **4.** The water level goes down a bit — no support

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**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](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/t11/)

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### Exam question 1 · formal language · right ✓ {#e1}

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Which of the following statements most accurately characterises the upward force exerted by water upon an immersed body?

- **1.** It is equal to the weight of the water displaced — **← Mova's choice** · **✓ the right answer** · score 8
- **2.** It is exerted only upon bodies that float — no support
- **3.** It is independent of the volume of the body — no support
- **4.** It is equal to the weight of the body in every case — score 7

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**Why:** It took the question to ask who or what does it. It chose option 1 with score 8, against 7 for the next best. Its support: lesson 11, line 11: «A steel ship floats because it is hollow and full of air, so the water it moves aside weighs more than the ship; squashed into a lump, it would sink.», reached through the remembered sentence the question matched. What matched: the same action «move» (+4); the same thing acted on «water» (+4). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/e1/)

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### Exam question 2 · formal language · wrong ✗ {#e2}

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Identify the principal reason for which a vessel constructed of steel remains afloat.

- **1.** The engines exert a continual upward force — **← Mova's choice** · no support
- **2.** Salt water exerts no downward force upon metal — no support
- **3.** Its hollow form displaces a weight of water exceeding its own — **✓ the right answer** · no support
- **4.** Steel is of lesser density than water — no support

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**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](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/e2/)

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### Exam question 3 · formal language · right ✓ {#e3}

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It is given that a quantity of salt is dissolved in water in which an egg has sunk. Ascertain the consequence.

- **1.** The egg descends more rapidly — no support
- **2.** The water becomes lighter — score 3
- **3.** The egg rises to float — **← Mova's choice** · **✓ the right answer** · score 5
- **4.** The egg becomes heavier — no support

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**Why:** It took the question to ask which statement is true. It chose option 3 with score 5, against 3 for the next best. Its support: lesson 11, line 15: «An egg sinks in tap water but floats when lots of salt is stirred in, and a rotten egg floats even in fresh water because gas has built up inside.», reached through a sentence linked to the one the question matched. What matched: the same action «float» (+3); the same doer «egg» (+2). · [the question and its options parsed, with trees and pragmatics](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/e3/)

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### Exam question 4 · formal language · wrong ✗ {#e4}

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Determine the function of the line marked upon the hull of a merchant vessel.

- **1.** It indicates the speed that the vessel may attain — **← Mova's choice** · no support
- **2.** It indicates the position of the engines — no support
- **3.** It indicates the port at which the vessel was registered — no support
- **4.** It indicates the greatest depth to which the vessel may safely be immersed — **✓ the right answer** · no support

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**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](https://md.mova.elamur.ai/free/en/corpora/questions/physics/11-floating-and-sinking/e4/)

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- ← previous: [10. Swings and pendulums](https://md.mova.elamur.ai/free/en/school-run/physics/10-swings-and-pendulums/)
- next →: [12. Floating in the real world: ice, submarines and…](https://md.mova.elamur.ai/free/en/school-run/physics/12-ice-submarines-and-balloons/)
- ↑ back to [Physics](https://md.mova.elamur.ai/free/en/school-run/physics/)