--- title: Senses: eyes and ears — a lesson of Mova's school · trees and pragmatics description: «Senses: eyes and ears», a lesson of the biology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Your eyes catch light and your ears catch vibrations in the air, and both turn what they catch into nerve signals that the brain makes into pictures --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/) [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/) / [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/) / Senses: eyes and ears # Senses: eyes and ears Lesson 69 of the biology course of Mova's primary school: 15 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/biology/69-senses-eyes-and-ears/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/0/) — Your eyes catch light and your ears catch vibrations in the air, and both turn what they catch into nerve signals that the brain makes into pictures and sounds. - [1](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/1/) — Walk out of a dark cinema into bright sunshine and you squint: the black dot in your eye, the pupil, shrinks fast, because the coloured ring around it, the iris, is a muscle that lets in less light. - [2](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/2/) — Inside the eye a lens, like a magnifying glass, throws an upside-down picture onto the back of the eye, and the brain turns it the right way up and even fills in a small blind spot where you see nothing at all. - [5](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/5/) — The pupil is a hole that lets light into the eye; the coloured iris around it is a muscle that makes the pupil smaller in bright light and bigger in the dark. - [6](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/6/) — The lens in the eye works like a magnifying glass and makes an upside-down picture on the retina at the back of the eye, and the brain turns it the right way up. - [7](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/7/) — Where the optic nerve leaves the eye there are no light cells, so each eye has a small blind spot that the brain usually fills in so we do not notice it. - [8](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/8/) — Cone cells for colour come in three kinds, most sensitive to red, green and blue light, and the brain mixes their signals into all colours; rod cells see in dim light but not in colour. - [9](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/9/) — About 1 in 12 boys and men and about 1 in 200 girls and women are colour blind, most often mixing up reds and greens. - [11](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/11/) — Carrots have vitamin A, which the eye needs to see in dim light, but eating extra carrots does not give night vision; the story spread in the Second World War and, many historians say, helped hide the use of radar. - [12](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/12/) — Bats are not blind: all bats can see, and many also find insects in the dark by echolocation, making high squeaks and listening for the echoes. - [13](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/13/) — Sound is vibration in the air: it shakes the eardrum, three tiny bones called the hammer, anvil and stirrup pass it on, and hair cells in the snail-shaped cochlea turn it into nerve signals. - [14](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/14/) — Sound reaches the nearer ear a tiny fraction of a second sooner and a little louder, and the brain uses these differences to tell where a sound comes from. - [15](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/15/) — The inner ear has three loops filled with fluid; when you spin, the fluid swirls, and after you stop it keeps moving for a moment, so you feel dizzy. - [16](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/16/) — Very loud sounds can damage the hair cells in the cochlea, which in people do not grow back; ringing ears after fireworks are a warning sign, and ear defenders help. - [17](https://md.mova.elamur.ai/free/en/corpora/school/biology/69-senses-eyes-and-ears/17/) — An echo is sound bouncing off a hard surface and coming back; sound travels about 340 metres a second in air, so an echo from a cliff 170 metres away comes back after about one second. - ← previous: [The brain and nerves](https://md.mova.elamur.ai/free/en/corpora/school/biology/68-the-brain-and-nerves/) - next →: [Senses: nose, tongue and skin](https://md.mova.elamur.ai/free/en/corpora/school/biology/70-senses-nose-tongue-and-skin/) - ↑ back to [Biology](https://md.mova.elamur.ai/free/en/corpora/school/biology/)