--- title: Diggers, cranes and cement mixers — a lesson of Mova's school · trees and pragmatics description: «Diggers, cranes and cement mixers», a lesson of the technology course of Mova's primary school, sentence by sentence with dependency trees and pragmatics. It begins: Building machines are giants with one big trick each. --- [Mova](https://md.mova.elamur.ai/free/en/) · [this page in HTML](https://mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/) [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/) / [Technology](https://md.mova.elamur.ai/free/en/corpora/school/technology/) / Diggers, cranes and cement mixers # Diggers, cranes and cement mixers Lesson 28 of the technology course of Mova's primary school: 22 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/technology/28-diggers-cranes-and-cement-mixers/). - [0](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/0/) — Building machines are giants with one big trick each. - [1](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/1/) — A digger scoops, a crane lifts, a mixer lorry keeps concrete moving, a roller squashes, and a pile driver hammers posts deep into the ground. - [3](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/3/) — The engine drives a pump that pushes oil into strong tubes called pistons, and oil cannot be squashed, so it pushes the arm with enormous force. - [4](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/4/) — This is called hydraulics. - [5](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/5/) — A tower crane works like a seesaw. - [6](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/6/) — The long arm carries the load on a trolley and cable, and heavy concrete blocks on the short arm balance it, so the crane does not tip over. - [7](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/7/) — All these machines are amazing to watch, and the only safe place to watch them from is behind the fence. - [8](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/8/) — Building sites are dangerous even when they look empty, so children never go in. - [9](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/9/) — A digger's engine drives a pump that pushes oil into pistons, called hydraulics, which move the arm and bucket with huge force; its tracks spread its weight so it does not sink in mud. - [10](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/10/) — Diggers swing round and their drivers cannot see behind them; never go onto a building site, and keep behind the fences. - [11](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/11/) — A tower crane has a tall mast and a long arm with a trolley and cable for the load, and heavy concrete weights on the short arm balance it; it grows taller by adding pieces to the mast as the building rises. - [12](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/12/) — A tower crane driver usually climbs a long ladder inside the mast and works high up in the cab for hours; cranes stop in high winds, and nobody stands under a load. - [13](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/13/) — A mobile crane is a crane on a lorry with an arm that slides out like a telescope; it puts out legs before lifting so it does not tip over. - [14](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/14/) — A cement mixer lorry keeps its drum turning so the concrete does not set; spiral fins inside mix it one way and push it out the other way. - [15](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/15/) — Concrete sets because of a chemical reaction with water, not because it dries; wet cement can burn skin. - [16](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/16/) — A bulldozer pushes earth and rubble with a big blade at the front, and its caterpillar tracks grip the ground; tracks were used on farm tractors before tanks. - [17](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/17/) — A dumper truck has a big bin that tips up to empty; the largest mining dump trucks carry hundreds of tonnes and have tyres taller than an adult. - [18](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/18/) — A road roller squashes soil and hot asphalt (the black stuff that roads are covered with) flat with heavy steel drums, and some shake thousands of times a minute to pack the ground better. - [19](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/19/) — A pile driver drives long posts, called piles, deep into the ground to hold up buildings by carrying their weight down to firm ground, and tall buildings can stand on piles deeper than a house is tall; it is so loud that workers wear ear protection. - [20](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/20/) — A cherry picker lifts workers on a platform at the end of a folding hydraulic arm, and they wear harnesses clipped to the platform; fire brigades use similar machines to reach high windows, and council workers use them to fix street lights. - [21](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/21/) — Hard hats protect heads from falling things, and hi-vis vests make workers easy to see; hi-vis means high visibility. - [22](https://md.mova.elamur.ai/free/en/corpora/school/technology/28-diggers-cranes-and-cement-mixers/22/) — Many dumper trucks used on building sites have 6 wheels. - ← previous: [Road and railway safety](https://md.mova.elamur.ai/free/en/corpora/school/technology/27-road-and-railway-safety/) - next →: [Tunnels and what lies under the street](https://md.mova.elamur.ai/free/en/corpora/school/technology/29-tunnels-and-under-the-street/) - ↑ back to [Technology](https://md.mova.elamur.ai/free/en/corpora/school/technology/)