---
title: The sky is blue because the gas in the air scatters blue light much… — Mirrors, rainbows and the blue sky · tree and pragmatics
description: The sky is blue because the gas in the air scatters blue light much more than red; from the Moon, with no air, the sky is black even by day. Who acts: sky, gas. A sentence of the lesson «Mirrors, rainbows and the blue sky» of the physics course of Mova's primary school with its dependency tree and t
---

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# Mirrors, rainbows and the blue sky, sentence 13

<!-- .ven lang=en -->
The sky is blue because the gas in the air scatters blue light much more than red; from the Moon, with no air, the sky is black even by day.

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**Who acts:** sky, gas · **What happens:** be, scatter · **To what, where:** blue light, Moon

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This is a sentence of the lesson «Mirrors, rainbows and the blue sky» of the physics course of Mova's primary school. The page gives its syntax tree — a dependency tree in the style of Universal Dependencies — and its pragmatics clause by clause: who acts (sky, gas), what happens, when and where, as Mova's frames read it from the tree.

## The tree {#tree}

```conllu
# sent_id = school:physics:021-mirrors-rainbows-and-the-blue-sky.lesson:13
# text = The sky is blue because the gas in the air scatters blue light much more than red; from the Moon, with no air, the sky is black even by day.
# source = school lesson (ours)
# course = physics
# lesson = 021-mirrors-rainbows-and-the-blue-sky.lesson
# annotation = Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): R5-strong ×2, R7-rel-agree ×1
1	The	the	DET	DT	Definite=Def|PronType=Art	2	det	_	_
2	sky	sky	NOUN	NN	Number=Sing	4	nsubj	_	_
3	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	cop	_	_
4	blue	blue	ADJ	JJ	Degree=Pos	0	root	_	_
5	because	because	SCONJ	IN	_	11	mark	_	_
6	the	the	DET	DT	Definite=Def|PronType=Art	7	det	_	_
7	gas	gas	NOUN	NN	Number=Sing	11	nsubj	_	_
8	in	in	ADP	IN	_	11	case	_	_
9	the	the	DET	DT	Definite=Def|PronType=Art	10	det	_	Agree=R5-strong|Haiku=11:det
10	air	air	NOUN	NN	Number=Sing	7	nmod	_	Agree=R5-strong|Haiku=11:compound
11	scatters	scatter	VERB	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	4	advcl	_	_
12	blue	blue	ADJ	JJ	Degree=Pos	13	amod	_	_
13	light	light	NOUN	NN	Number=Sing	11	obj	_	_
14	much	much	ADV	RB	_	15	advmod	_	_
15	more	more	ADV	RBR	Degree=Cmp	11	advmod	_	_
16	than	than	ADP	IN	_	17	case	_	_
17	red	red	ADJ	JJ	Degree=Pos	15	obl	_	_
18	;	;	PUNCT	:	_	30	punct	_	_
19	from	from	ADP	IN	_	21	case	_	_
20	the	the	DET	DT	Definite=Def|PronType=Art	21	det	_	_
21	Moon	Moon	PROPN	NNP	Number=Sing	30	obl	_	_
22	,	,	PUNCT	,	_	25	punct	_	_
23	with	with	ADP	IN	_	25	case	_	_
24	no	no	DET	DT	PronType=Neg	25	det	_	_
25	air	air	NOUN	NN	Number=Sing	21	conj	_	_
26	,	,	PUNCT	,	_	21	punct	_	_
27	the	the	DET	DT	Definite=Def|PronType=Art	28	det	_	_
28	sky	sky	NOUN	NN	Number=Sing	30	nsubj	_	_
29	is	be	AUX	VBZ	Mood=Ind|Number=Sing|Person=3|Tense=Pres|VerbForm=Fin	30	cop	_	_
30	black	black	ADJ	JJ	Degree=Pos	4	parataxis	_	Agree=R7-rel-agree|Haiku=4:conj
31	even	even	ADV	RB	_	33	advmod	_	_
32	by	by	ADP	IN	_	33	case	_	_
33	day	day	NOUN	NN	Number=Sing	30	obl	_	_
34	.	.	PUNCT	.	_	4	punct	_	_
```

## Pragmatics {#pragmatics}

<!-- .note -->
No stored speech act for this sentence.

<!-- .fr -->
| # | verb | tense, mood | who | what, whom | to whom | where | when | other | roles by |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1 | **is** | present | the sky |  |  |  |  | blue *property* | tree rules |
| 2 | **scatter** | present | the gas  the air | blue light |  |  |  |  | vn spray-9.7-1 «NP V NP.theme»: agent=Agent light=Theme |
| 3 | **is** | present | the sky |  |  | the Moon and no air | day | black *property* | tree rules |

<!-- .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.

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**Licence: [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/)**, as the whole of Mova corpus 0.4, of which this treebank (the agreed school, `mova-school-agreed-en.conllu`) is part. The lessons were written for Mova's primary school. Sentence `school:physics:021-mirrors-rainbows-and-the-blue-sky.lesson:13`.

**The tree:** Mova annot: Rust (en) → Haiku 5.5 (medium, Batches API) patches; gates UD 2.18; agreed by treeagree rules (Stanza, Trankit, spaCy trf): R5-strong ×2, R7-rel-agree ×1. **The frames** are read from the tree by Mova's frames reader (`prag`) when this page is built, the lesson read in order, so a pronoun may be resolved from an earlier sentence.

See the [release 0.4](https://md.mova.elamur.ai/free/en/releases/0.4/).

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