EXERCISES

Vladislav Schumilin BPS-10-01

Earth Ride Movie

DESIGNERS: Y.V. GAREYEVA, E.G. SHAIKHUDTINOVA

Vocabulary


1. immense - огромный

2. to depend on - зависеть

3. amount - количество

4. to survive - выживать

5. substance - вещество

6. liquid - жидкий

7. water vapour - водяной пар

8. drop - капля

9. molecule - молекула

10. hydrogen - водород

11. oxygen - кислород

12. average - средний

13. extraterrestrial - внеземной

14. steam - пар

15. to envelope - окутывать

16. greenhouse effect - парниковый эффект

17. to evaporate - испаряться

18. to run out - заканчиваться

19. Earth’s crust - земная кора

20. core - ядро

21. to erupt - извергаться

22. pressure - давление

23. nutrient - питательное вещество

24. diverse - разнообразный

25. availability - доступность

26. crucial - главный

27. to store - хранить

28. to collide - сталкиваться

29. to swell - набухать

30. to replenish - пополнять

31. precipitation - выпадение осадков

32. to release - высвобождать

33. hail - град

34. to melt - таять

35. flood - наводнение

36. to carve - высекать

37. to expel - (зд.) испаряться

38. deluge - потоп

39. desertification - опустынивание

40. snow flake - снежинка

41. blizzard - снежная буря

42. glacier - ледник

43. to blanket - покрывать

44. unique - уникальный

45. solid - твердое состояние

46. sink (sank, sunk) - тонуть

47. to float - плавать

48. to prevent - предотвращать

49. roller coaster - американские горки

50. astonishing - поразительный

51. rotation - вращение

52. to predict EXERCISES - предсказывать

53. global warming - глобальное потепление

54. to shrink - сокращаться

55. impact - влияние

56. to disappear - исчезнуть

57. precious - ценный


TEXT

Earth is the planet of immense variety but every form of life depends on water and water gets everywhere whether we like it or not.

Water is shared between all living things but there is only a limited amount of it. Where is it all being? Where is it all going?

All creatures including you depend on water. None can survive without it. You are 2/3 of water and the water inside your body right now has had a remarkable history. Some of the water you drink today once was in the EXERCISES deepest oceans. Whenever you drink a glass of water you become a part of water cycle.

Water is the only substance on the Earth that can naturally exist in all three basic forms: ice, liquid and water vapour. From the driest deserts to the snow peaks water is constantly recycling around the Earth and at any moment there are 12, 000 billion tons of it in the atmosphere circling the globe.

What is so special about the water? It has got no colour, no taste and no smell. To find out let’s have a look inside a single drop. The EXERCISES water molecule H2O consists of two atoms of hydrogen and one of oxygen. Each molecule is connected to the next by electrical forces called hydrogen bonds. These bonds will help discover what makes water unique.

Water is the most common substance now on the Earth, but once upon a time it wasn’t here at all.

How did water first appear on the Earth? Some part of water came on our planet from outer space when massive quantities of oxygen and hydrogen combined to form space ice. An average comet is made up of billion tons of ice EXERCISES. We and all other forms of life on the planet partly owe our existence to this extraterrestrial water. Just think that makes you a part of extraterrestrial too!

The other source of water is from oxygen and hydrogen combining deep within the forming planet, the Earth. They produce steam, boiling water vapour, which emerges from the raptures of the Earth such as geizers and volcanic springs.

Over the next 3 billion years our planet’s atmosphere became saturated with water vapour. This vapour enveloped the Earth to protect the planet from the sun rays. It also trapped the sun heat. So EXERCISES each day the Earth’s atmosphere began to warm. Without this original greenhouse effect the average temperature on the Earth would be -18°C and our planet would be a frozen wasteland. Life as we know it today could have never begun.

Eventually the atmosphere had warmed enough for rain to fall. Rain water filled the oceans and energy of the sun began to drive the great cycle of water around the planet. And we are all parts of the same drop. The rain that fell then has by now circled the Earth about 8 million times. The water EXERCISES cycle runs on solar power. The sun’s heat evaporates water from the surface of the seas. During this process all its salt is lost leaving just clean fresh water spread across the globe.

But some of the water is lost each day in the upper layers of the atmosphere. Does this mean that one day our supply of water will run out? To answer this question we are going to the centre of the Earth.

30 kilometers beneath our feet temperatures exceed 1000°C. This is the beginning of the mantle, the layer between the Earth’s crust and the core. Down EXERCISES here it is mostly hard rock but in deeper parts there is also water. Maybe it’s 10 times the volume of all global oceans. This giant reservoir replaces the water lost in the space. It releases the steam when volcanoes erupt.



Volcanoes shaped our primitive planet long before any life evolved. Then some of them were submerged but they continued to erupt under the water releasing steam straight into the sea.

More water was released to the oceans through ruptures in the sea floor. The black smokers are natural chimneys on the seabed that spill out superheated water EXERCISES black with minerals. It’s supposed that 3.8 billion years ago the evolution had begun in these deep waters and life was evoluted with the help of water.

Microbes are still living 2.5 km down the water surviving in the immense pressure. They exist due to minerals and volcanic heat.

Sea water was a perfect place for life to start with stable temperature, physical support and ready supply of nutrients. And evolution spread into the oceans. Strong currents powered by the sun spread life across the globe. As time went by the seas became richer and the animals became EXERCISES more diverse.

Today the oceans teem with life in all its shapes and sizes. It’s quite relatively recently that evolution reached dryland. Without the ocean’s stable temperature and physical support creatures’ bodies and their behaviours had to alter radically. They were like aliens in another world. Water availability became the crucial key to survival. What land animals needed was new ways to conserve water inside their bodies. As more time passed other animals learned how to manage without so much water. Huge reptiles started to lay their eggs on land with harder shells to stop them dehydrating.

The EXERCISES birds had owned water-tight egg design and eventually it helped them to colonize some of the most hostile places of the planet.

Mammals are good at storing water in their bodies. Some have even adapted to life in the desert. But even this one can’t completely manage without water’s life-giving powers. A camel can drink about 120 liters at a single sitting and all this water contains molecules already drunk by many other animals of 100 millions of years of evolution.

Our world is a closed system like a glass. It holds only a limited amount of EXERCISES water. What happens to a water droplet when it leaves the sea and evaporates into the sky?

As the water vapour rises it expands and cools. It condenses around microscopic particles of dust. And a cloud is born. As water droplets in a cloud collide they swell and fall as rain. The rain replenishes what was lost and the cycle begins again.

The water cycle is a constant process of evaporation, condensation and precipitation.

In a cloud water can exist in all three forms as liquid, vapour and as particles of ice. As molecules shift from one form to another the EXERCISES hydrogen bonds connecting them break and reconnect again sucking in releasing energy. But this is only the beginning of a water droplet epic journey from the clouds back to the sea. Sometimes the cycle will slow but then it will speed up again for the next ride.

But how does it all begin?

Most rains start as ice. Summer storm clouds are mostly made up of super cooled water particles and when one of this collides an ice crystal floating in the cloud it grows into a ball of ice – hail storm. Gravity takes over and they EXERCISES fall down to Earth. But many hail storms can’t survive this trip, they melt as they pass lower warmer air layer and then they transform into large drops of rain.

What happens to a water drop next?

It depends on where it falls. These water drops are filled with energy. To small insects it is equivalent to artillery combat. In mountain areas a storm can lead to a flash flood. In the space of 10 km water can reduce a granite rock to a pebble just 2 cm wide. Given enough time water can carve up the entire landscape EXERCISES. Once water loses high speed it becomes a gentle cruise. Now animals can take advantage of the water in amazing ways.

A tree is about 2/3 water and water travels through it at amazing speed up to 60 meters per hour.

Plants need water for photosynthesis. From a leaf it’s a short way for water to reach the other forms of life. A monkey eats a juicy leaf and the Earth ride takes another turn.

Trees make so much water vapour that large forests actually create their own weather. Half of all rain falls just in one place the Amazon basin EXERCISES in South America and 70 % of that rain is expelled as vapour by the trees below. Eventually every droplet makes its way to the mighty Amazon River which carries 1/5 of the world’s running fresh water.

At last this water cycle is over and each droplet finally returns to where it started out. An average water molecule will stay here for two thousand years or more until one day it will evaporate and start its epic ride all over again. By that time ocean currents may carry it to the other side of the world.

Water covers more than 2/3 of Earth’s EXERCISES surface and only 30 % is dry land. And the amount of life that can exist on land depends on how much water is available. Plants are the foundation of the food chain without water they can’t grow. They carry water up from their roots by the process called capillary action and the driest land can spring a life. Water provides mechanical support without it a young plant soon withers. But given a little drink it may live again.

The drier the climate the more water cycle controls animals’ lives. In the East Africa savanna there are only two EXERCISES short rainy seasons producing only about a meter of rainfall a year. It’s too little for trees to grow instead savanna’s landscape is dominated by grass. And when the rains do come it’s a deluge. In the driest areas puddles don’t last long. Deserts are constantly shifting in size according to the subtle changes in the climate. But only in the past century desertification began to increase. Deserts now cover 1/5 of the Earth’s land surface. There is a desert in Chile where rain has never fallen.

But the Earth is not always made of EXERCISES deserts and sand. In fact the coldest place on Earth is largely a desert. There is water in the Antarctic but it is locked up as ice.

So where does all this frozen water come from?

When conditions are right ice crystals form in the clouds. They grow until they are heavy enough to form snowflakes. All snowflakes are six-sided as every water molecule bonds to five others. They come in a marvelous variety of shapes. But each one has the same basic oxygon symmetry. When blizzards fall from the mountain tops the snow compacts, forms a EXERCISES river and compressed ice becomes a glacier. It takes thousands of years for a single ice crystal to travel the length of a large glacier. But one day it will be released either as melt water or as a part of an iceberg. Today about a tenth of our land is blanketed by ice and ice like liquid water is unique. It is strong enough to carve up a bed rock and yet it is so light that it floats in water.

In fact water is the only known substance to have a solid lighter than its liquid. And if EXERCISES it didn’t, what would happen to the penguins? If ice sank as other solids do, we wouldn’t be here either. Life on the Earth could never have evolved. During the winters seas would freeze solid. Ice would reflect the sun’s heat back into the space and the planet could never have formed.

But why does ice float? Why does that prevent our seas from freezing?

When frozen water molecules form a rigid six-sided structure that is less tense than liquid water. There are gaps between the molecules that make them buoyant. Water is the densest EXERCISES at about +4°C. This temperature is beneath the ice. So the sea remains unfrozen and it is a home to a spectacular way of life. If the roller coaster switches its direction the effect would be very dramatic at the poles.

And at no time in our history the water cycle has changed so rapidly and dramatically as it is changing right now. What is the next bend in the Earth ride no one knows.

In recent years humans have diverted vast amounts of water for our cities and our industry. We build some of our greatest EXERCISES cities close to water, we use it for decoration and because we like its sound.

And to stay hydrated we should drink at least 2 liters of it every day. Since it’s started out as a cosmic ice drifting in outer space, this water has traveled a long way to get to you.

But can we or should we control the water roller coaster?

Moving millions of tons of water the world has had an astonishing effect. We’ve actually slowed down the Earth rotation. A day is now longer than it was a century ago. Many factors could EXERCISES affect the water cycle over the next centuries or so but scientists predict the largest impact will come from the giant climate shift known as global warming. 1998 was the warmest year on record and in 2001 melt water was discovered in North Pole. Antarctic icebergs are also shrinking. The impact of this climate change in both poles is not clear but sea ice seems to be disappearing. And it’s a trouble for some animals including polar bear. At this point no one can be sure which way water roller coaster will go next. But one thing is sure water remains EXERCISES the most precious resource for our life.

EXERCISES


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