---
title: State the reason for which a vacuum flask preserves the temperature… — Keeping warm and keeping cool: insulat… · tree and pragmatics
description: State the reason for which a vacuum flask preserves the temperature of its contents in either direction. Exam question 4 of lesson 25 «Keeping warm and keeping cool: insulation and sweat» of the physics course of Mova's primary school, with the dependency tree and pragmatics of the question and of e
---

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# Exam question 4 · Keeping warm and keeping cool: insulation and sweat

<!-- .ven lang=en -->
State the reason for which a vacuum flask preserves the temperature of its contents in either direction.

<!-- .vintro -->
**Mova's choice:** option 4 · **The right answer:** option 3 · wrong ✗ · **Who acts:** vacuum flask · **What happens:** preserve · **To what, where:** temperature

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This is exam question 4 of lesson 25 «Keeping warm and keeping cool: insulation and sweat» of the physics course of Mova's primary school, asked in stiff, formal language. The page gives the question's syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause, then the 4 options as the student saw them, each with its tree and pragmatics. Every text is parsed by Mova itself. How the student answered it, with the score of every option and why: [the test at school](https://md.mova.elamur.ai/free/en/school-run/physics/25-keeping-warm-and-keeping-cool/#e4).

## The question {#question}

```conllu
# sent_id = question:physics:25-keeping-warm-and-keeping-cool:e4:1
# text = State the reason for which a vacuum flask preserves the temperature of its contents in either direction.
1	State	state	NOUN	NN	Number=Sing	3	compound	_	_
2	the	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
3	reason	reason	NOUN	NN	Number=Sing	0	root	_	_
4	for	for	ADP	IN	_	5	case	_	_
5	which	which	PRON	WDT	PronType=Rel	9	obl	_	_
6	a	a	DET	DT	Definite=Ind|PronType=Art	8	det	_	_
7	vacuum	vacuum	NOUN	NN	Number=Sing	8	compound	_	_
8	flask	flask	NOUN	NN	Number=Sing	9	nsubj	_	_
9	preserves	preserve	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	3	acl	_	_
10	the	the	DET	DT	Definite=Def|PronType=Art	11	det	_	_
11	temperature	temperature	NOUN	NN	Number=Sing	9	obj	_	_
12	of	of	ADP	IN	_	14	case	_	_
13	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	14	nmod:poss	_	_
14	contents	contents	NOUN	NNS	Number=Ptan	11	nmod	_	_
15	in	in	ADP	IN	_	17	case	_	_
16	either	either	DET	DT	PronType=Ind	17	det	_	_
17	direction	direction	NOUN	NN	Number=Sing	14	nmod	_	SpaceAfter=No
18	.	.	PUNCT	.	_	3	punct	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **preserve** | present | a vacuum flask | the temperature of flask's contents in either direction |  |  |  | for the State reason | vn defend-72.3 «NP V NP»: agent=Agent temperature=Beneficiary |

<!-- .note -->
One row per clause the reader finds. «not said here»: a role filled from the clause above. «roles by»: a VerbNet class and frame when one fits the verb, else the reader's rules on the tree.

## The options {#options}

### Option 1 {#o1}

<!-- .ven lang=en -->
It distinguishes hot contents from cold

```conllu
# sent_id = question:physics:25-keeping-warm-and-keeping-cool:e4:o1:1
# text = It distinguishes hot contents from cold
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	distinguishes	distinguish	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	hot	hot	ADJ	JJ	Degree=Pos	4	amod	_	_
4	contents	contents	NOUN	NNS	Number=Ptan	2	obj	_	_
5	from	from	ADP	IN	_	6	case	_	_
6	cold	cold	ADJ	JJ	Degree=Pos	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **distinguish** | present | It | hot contents |  |  |  | from cold | vn distinguish-23.5-1 «NP V NP.theme PP.co-theme»: agent=Agent contents=Theme from cold=Co-Theme |

### Option 2 {#o2}

<!-- .ven lang=en -->
It contains a heating element

```conllu
# sent_id = question:physics:25-keeping-warm-and-keeping-cool:e4:o2:1
# text = It contains a heating element
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	contains	contain	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	a	a	DET	DT	Definite=Ind|PronType=Art	5	det	_	_
4	heating	heating	NOUN	NN	Number=Sing	5	compound	_	_
5	element	element	NOUN	NN	Number=Sing	2	obj	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **contain** | present | It | a heating element |  |  |  |  | vn comprise-107.2-2 «NP V NP»: agent=Pivot element=Theme |

### Option 3 · ✓ the right answer {#o3}

<!-- .ven lang=en -->
The near absence of air between its walls impedes the passage of heat

```conllu
# sent_id = question:physics:25-keeping-warm-and-keeping-cool:e4:o3:1
# text = The near absence of air between its walls impedes the passage of heat
1	The	the	DET	DT	Definite=Def|PronType=Art	3	det	_	_
2	near	near	ADJ	JJ	Degree=Pos	3	amod	_	_
3	absence	absence	NOUN	NN	Number=Sing	9	nsubj	_	_
4	of	of	ADP	IN	_	5	case	_	_
5	air	air	NOUN	NN	Number=Sing	3	nmod	_	_
6	between	between	ADP	IN	_	8	case	_	_
7	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	8	nmod:poss	_	_
8	walls	wall	NOUN	NNS	Number=Plur	5	nmod	_	_
9	impedes	impede	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
10	the	the	DET	DT	Definite=Def|PronType=Art	11	det	_	_
11	passage	passage	NOUN	NN	Number=Sing	9	obj	_	_
12	of	of	ADP	IN	_	13	case	_	_
13	heat	heat	NOUN	NN	Number=Sing	11	nmod	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **impede** | present | the near absence of air between absence's walls | the passage of heat |  |  |  |  | vn discourage-64.5-1 «NP V NP»: agent=Causer passage=Eventuality |
| 2 | **absent** |  |  | air between absence's walls |  |  |  |  | nom absence «state transitive»: of=patient |
| 3 | **pass** |  | heat |  |  |  |  |  | nom passage «act intransitive»: of=agent |

### Option 4 · ← Mova's choice {#o4}

<!-- .ven lang=en -->
It generates cold within its walls

```conllu
# sent_id = question:physics:25-keeping-warm-and-keeping-cool:e4:o4:1
# text = It generates cold within its walls
1	It	it	PRON	PRP	Case=Nom|Gender=Neut|Number=Sing|Person=3|PronType=Prs	2	nsubj	_	_
2	generates	generate	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	0	root	_	_
3	cold	cold	ADJ	JJ	Degree=Pos	2	xcomp	_	_
4	within	within	ADP	IN	_	6	case	_	_
5	its	its	PRON	PRP$	Case=Gen|Gender=Neut|Number=Sing|Person=3|Poss=Yes|PronType=Prs	6	nmod:poss	_	_
6	walls	wall	NOUN	NNS	Number=Plur	2	obl	_	_
```

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **generate** | present | It |  |  |  |  | within its walls; cold *property* | vn grow-26.2.1 «NP.patient V PP.product»: agent=Patient |

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**Text:** the tests of Mova's primary school, written for Mova (`world/data/school/`), as the course runner gave them to the student. **Trees:** Mova's own parse — the `en` model on the CPU, when the site is built — not checked by a teacher; they may be wrong. **Frames:** Mova's frames reader (`prag`), each text read on its own. Elamur Cosmic License.

<!-- /div -->

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