--- title: What sound is: wobbles in the air — a lesson of Mova's school · trees and pragmatics description: «What sound is: wobbles in the air», a lesson of the physics course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Every sound starts with something wobbling very fast: a guitar string, a drum skin, or the vocal cords in your throat. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/) [home](https://md.mova.elamur.ai/free/en/) / [corpora](https://md.mova.elamur.ai/free/en/corpora/) / [school](https://md.mova.elamur.ai/free/en/corpora/school/) / [Physics](https://md.mova.elamur.ai/free/en/corpora/school/physics/) / What sound is: wobbles in the air # What sound is: wobbles in the air Lesson 17 of the physics course of Mova's primary school: 17 sentences, each with its syntax tree and pragmatics. The lessons are written for Mova, and their agreed trees are part of Mova corpus 0.4 (CC BY-SA 4.0). How Mova does on its tests: [the lesson at school](https://md.mova.elamur.ai/free/en/school-run/physics/17-what-sound-is-wobbles-in-the-air/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/0/) — Every sound starts with something wobbling very fast: a guitar string, a drum skin, or the vocal cords in your throat. - [1](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/1/) — The wobbling thing shoves the air next to it, that air shoves the next bit, and the wobble travels outwards until it reaches your ear, a bit like a push passed along a queue. - [2](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/2/) — Put your hand on your throat and hum, and you can feel your voice buzzing; stop the wobble, and the sound stops too. - [3](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/3/) — Fast wobbles sound high and slow wobbles sound low, so a tiny ukulele squeaks and a huge double bass booms. - [4](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/4/) — Sound needs something to travel through, air, water or solid things, so in the emptiness of space there is no sound at all. - [5](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/5/) — Sound is a wobble, or vibration, passed on through air, water or solid things. - [6](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/6/) — A plucked guitar string wobbles back and forth very fast and pushes the air in little waves; press a finger on it and the sound stops. - [7](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/7/) — When you hum, your vocal cords wobble as air from your lungs passes them, and you can feel the buzz on your throat. - [8](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/8/) — Rice on a drum jumps when you bang it, because the drum skin wobbles up and down; hit gently and the rice barely moves and the sound is quiet. - [9](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/9/) — Short, thin, tight strings wobble fast and sound high; long, thick, slack strings wobble slowly and sound low; blowing across bottles with different amounts of water gives different notes, because the air inside wobbles at different speeds. - [10](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/10/) — An echo is sound bouncing back off a hard, flat surface such as a cliff; the longer the echo takes to come back, the further away the cliff is. - [11](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/11/) — Hard bare walls bounce sound back, while soft curtains, carpets and sofas soak it up, so a furnished room hardly echoes. - [12](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/12/) — A bat finds its way in the dark by making very high squeaks and listening for the echoes. - [13](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/13/) — Ships use echoes under water, called sonar, and doctors use very high sounds, called ultrasound, to see inside the body. - [14](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/14/) — Dogs can hear much higher notes than people can, and people hear the highest notes less and less as they grow older. - [15](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/15/) — Sound travels further and faster in water than in air, and whale songs can carry hundreds of kilometres. - [16](https://md.mova.elamur.ai/free/en/corpora/school/physics/17-what-sound-is-wobbles-in-the-air/16/) — In empty space there is nothing to carry the wobble, so no sound can travel; real astronauts talk to each other by radio. - ← previous: [Pressure tricks: pumps, tyres and vacuums](https://md.mova.elamur.ai/free/en/corpora/school/physics/16-pressure-tricks-pumps-tyres-vacuums/) - next →: [Thunder, sirens and how fast sound travels](https://md.mova.elamur.ai/free/en/corpora/school/physics/18-thunder-sirens-and-how-fast-sound-travels/) - ↑ back to [Physics](https://md.mova.elamur.ai/free/en/corpora/school/physics/)