Toshkent kimyo texnalogiyalar instituti

LESSON 3 WATER

1.Read the text and translate

Water is one of the commonest of all substances, and without it life would be impossible. The seas and oceans cover about seventy per cent of the Earth's surface but water is also contained in the soil, in the atmosphere and in all living things. More than half of the human body consists of water, which also forms a large part of the food we eat, especially vegetables and fruit. Man can live as long as nine days or more without food, but we cannot live long without water.

Water exists as a substance in three states: ice, which melts at 0˚ degrees Centigrade; liquid water and steam, the latter is formed when water boils at 100˚ degrees Centigrade.

Water differs from other liquids. It expands when cooled from 0˚ Centigrade, contracts when heated from 0˚ to 4˚ Centigrade, and reaches its maximum density at 4˚ Centigrade. No other liquid possess this property. Pure water is rarely found in nature. This is because water is able to dissolve so many substances from the air, the soil and rocks.

The sun’s heat causes the surface sea water to evaporate, or change into vapor, leaving behind the salt and other minerals. This explains why the seas are so much more salty than rivers flowing into them.

Suv eng keng tarqalgan moddalardan biridir va u holda hayot imkonsiz bo'lar edi. Dengiz va okeanlar yer yuzasining yetmish foizini qoplaydi, ammo suv tuproqda, atmosferada va barcha tirik mavjudotlarda ham mavjud. Inson tanasining yarmidan ko'pi suvdan iborat bo'lib, biz ovqatlanadigan oziq-ovqatning katta qismini, ayniqsa, sabzavot va mevalarni tashkil qiladi. Bir kishi to'qqiz yoki undan ortiq kun davomida oziq-ovqatsiz yashashi mumkin, ammo biz uzoq vaqt suvsiz yashay olmaymiz.

Suv uchta holatda modda sifatida mavjud: 0 daraja Selsiy haroratida eriydigan muz; suyuq suv va bug', ikkinchisi suv 100 daraja Selsiy haroratida qaynatilganda hosil bo'ladi.

Suv boshqa suyuqliklardan farq qiladi. 0 daraja Selsiy bilan sovutilganda kengayadi, 0 dan 4 darajagacha qizdirilganda siqiladi va 4 daraja Selsiyda maksimal zichlikka etadi. Boshqa hech qanday suyuqlik bu xususiyatga ega emas. Toza suv tabiatda kamdan-kam uchraydi. Buning sababi shundaki, suv havo, tuproq va toshlardan juda ko'p moddalarni eritib yuborishi mumkin.

Quyosh issiqligi sirt dengiz suvini bug'lanadi yoki bug'ga aylanadi, tuz va boshqa minerallarni qoldiradi. Bu nima uchun dengizlar ularga oqib tushayotgan daryolarga qaraganda ancha sho'r ekanligini tushuntiradi.