--- title: Floating and sinking: the push of water — a lesson of Mova's school · trees and pragmatics description: «Floating and sinking: the push of water», a lesson of the world course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: When you put something in water, the water pushes it upwards. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/) [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/) / [World](https://md.mova.elamur.ai/free/en/corpora/school/world/) / Floating and sinking: the push of water # Floating and sinking: the push of water Lesson 83 of the world course of Mova's primary school: 23 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/world/83-floating-and-sinking/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/0/) — When you put something in water, the water pushes it upwards. - [1](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/1/) — This push is called upthrust. - [2](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/2/) — You can feel it when you try to push a beach ball under the water and it pushes back up. - [3](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/3/) — An object in water pushes some water out of the way; we say it displaces the water. - [5](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/5/) — This was discovered over 2,000 years ago by the Greek thinker Archimedes. - [6](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/6/) — If the upthrust can grow as big as the object's weight, the object floats; if the object sinks fully under and the upthrust is still smaller than its weight, it sinks. - [7](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/7/) — A lump of clay sinks, but shaped into a hollow boat it pushes aside much more water and floats. - [8](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/8/) — Salty water is heavier than the same amount of fresh water, so it pushes up harder. - [9](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/9/) — That is why people float easily in the very salty Dead Sea, and why a ship sits a little higher in the sea than in a river. - [10](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/10/) — A submarine can choose to float or sink. - [11](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/11/) — It lets water into its tanks to become heavier and dive, and blows the water out with air to become lighter and rise. - [12](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/12/) — Water pushes up on anything placed in it; this push is called upthrust. - [13](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/13/) — A floating object pushes aside, or displaces, some water. - [14](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/14/) — The upthrust equals the weight of the water that the object pushes aside. - [15](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/15/) — An object floats when the upthrust is equal to its weight. - [16](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/16/) — A hollow shape pushes aside more water than a solid lump of the same material. - [17](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/17/) — The more cargo a ship carries, the lower it sits in the water. - [18](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/18/) — Salt water gives more upthrust than fresh water. - [19](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/19/) — A submarine dives by filling its tanks with water and rises by blowing them out with air. - [20](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/20/) — Many fish have a swim bladder, a bag of gas that helps them float at the depth they want. - [21](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/21/) — Ice floats because water expands when it freezes, so ice is lighter than the same amount of water. - [22](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/22/) — Oil floats on water because it is less dense than water: a cupful of oil weighs less than a cupful of water. - [23](https://md.mova.elamur.ai/free/en/corpora/school/world/83-floating-and-sinking/23/) — Things feel lighter in water because the upthrust holds up part of their weight. - ← previous: [Heat and temperature: how things warm and cool](https://md.mova.elamur.ai/free/en/corpora/school/world/82-heat-and-temperature/) - next →: [Mirrors, shadows and colours](https://md.mova.elamur.ai/free/en/corpora/school/world/84-mirrors-shadows-colours/) - ↑ back to [World](https://md.mova.elamur.ai/free/en/corpora/school/world/)