Tento článok bol vytlačený zo stránky https://referaty.centrum.sk


Weather, flora, fauna, environment


A year has 12 months, 52 weeks and 365 days. Every fourth year has February 29 days. This year is called a leap-year. During a year exchanges four seasons. Spring, summer, autumn and winter. Each season has about 3 months and is atractive in some way.

Spring is a beautiful season. Begins on 21st March. Many people think it is the most beautiful season of all. The trees blossom and forest animals wake up from a winter sleep. All the landscape turns green and the days get longer. There are flowers in the meadows and in the gardens. Plants, trees and grass are green. Birds and beetles start flying around and small animals are born.
In spring the weather gets warmer. In March, however, there is not much sunshine and often rains. In April the weather is still changeable. The sky is cloudless and suddenly becomes overcast and icy winds begin blowing. It looks like rain and a few minutes later it is hailing. It lasts only a short while and it clears up again. There is a rainbow in the sky. People take off their raincoats and close their umbrellas. In the streets there are puddles and a lot of mud. After spring comes summer.

Summer is the warmest season of the year. June 21st is the date when summer begins. The temperature is mostly high above zero. It is not very rainy, therefore it is dry and there are sunny days. The days are longer and nights shorter than in winter. In the morning it is often misty but the fog is falling during the day and sun is shining. Suddenly a storm often comes in summer. It is usually windy before a storm and it is sultry. The sky is dark and it is thundering and we can see lightning. Usually the rain is heavy but short. Most people like the summer time. They can go to the seaside to spend their holidays. Some of them like staying in a tent and others going to their weekend/houses. Children needn’t go to school. Fruits ripen, the fields are yellow and at the end of the summer there is a harvest.

Autumn is a season full of colours. On the 23rd of September autumn comes. The leaves get yellow, red and brown and fall down. The days are shorter and nights longer than in summer. the weather gets colder and it is usually cloudy and foggy. There are showers or heavy rains. It is often misty all day. People gather fruits and vegetables in their gardens. Children enjoy flying a kite.

Winter is the coldest season of a year. Comes on December 21st, but it often begins earlier. When the temperature is below zero. everybody is freezing. There is a lot of snow in the mountains. The trees are bare and the whole landscape is covered with snow. People like going to the mountains and skiing. Rivers are frozen over and children like skating on the ice. There are some days in winter when snow falls heavily all day. There are snow/drifts everywhere. Children ate happy, they can practise sledging or making a snowman. But the adults are often unhappy. It is slippery on the streets and it is dangerous to use a car. When the temperature is above zero, the snow begins to thaw. Then it is muddy.

The environment means surroundings in which people, animals and plants develop and exist. More simplified it’s the world in which we live. The science that studies the relationship between different life forms in nature is ecology. Today the most serious ecological problems are: the pollution of the air, water and soil, the destruction of ecosystems and its balance, the disappearance of species of animals and plants, the weather changes, acid rains, the warming up of the earth surface, the destruction of tropical rainforests and breaking of the ozone layer. These damages are caused by the man himself and his technical progress.

Global warming and greenhouse effect
Scientists say the temperature of the earth could rise by 3°C over the next 50 years. This may cause draught in some parts of the world and floods in others, as ice at the North and South Poles begins to melt and sea levels rise. This is caused by the greenhouse effect. Normally, heat from the sun warms the earth and then escapes back into space but carbon dioxide and other gases in the atmosphere trap the sun’s heat and this is slowly making the earth warmer. And where does the CO2 come from? Well, people and animals breathe in oxygen and breathe out CO2. Trees take CO2 from the air and produce oxygen. But we produce CO2 also when we burn coal, oil, petrol, gas or wood. In the last few years people have burned huge areas of rainforests. This means that there are fewer trees and consequently more carbon dioxide.

There are two reasons for destroying the world’s forests: land and wood. The land is needed for crops and wood is exported and used for buildings or made into furniture. Unfortunately, many rainforests grow on poor soils and when the trees are cut down, the soil is washed away by the rain or blown away by the wind soon, and the area may turn to desert. But many plants and animal species that live there could become extinct. All of us are to blame for this disaster. However, some people can’t sit passively.

The ozone layer and ozone hole
The ozone layer is a layer of gas high above the surface of the earth that helps to protect it from the sun’s ultraviolet radiation, which can damage our skin and cause cancer. Scientists have recently discovered holes in the ozone layer, caused by substances called CFCs (chlorofluorocarbons). CFCs are used in refrigerator, aerosol cans and in the manufacture of some plastic products. Some companies now make aerosols that don’t contain CFCs, and these are often marked ozone-friendly.Pollution
Factories, power stations and motor vehicles pump large amounts of carbon dioxide and other waste gases into the air. This is the major cause of the green house effect. A lot of petrol contains lead, which is very poisonous and can cause brain damage in children. Many people now prefer using unleaded petrol. Some poisonous gases dissolve in water in the atmosphere and then fall to the earth as acid rain. Acid rain damages trees and buildings, and can kill fish in lakes and rivers. Rivers can also be polluted by industrial waste from factories and chemical fertilizers and pesticides used by farmers.

There are several groups which try to protect the environment. The most famous group is Greenpeace which makes campaigns in many countries around world. They have made campaigns against hunting whales, pollution in the North Sea, nuclear power and testing of nuclear weapons and many others issues. Greenpeace supporters organize demonstrations and they also take direct actions. Another important environmental group is Friends of the Earth. They have led campaigns against global warming, the destruction of the rain forests.
There is also a Green Party, which is a political party in Britain.
The oldest is the National Trust which was set up in 1895 to protect parks, buildings and monuments in Britain.
Royal Society for the Protection of Birds.

In the world there are a lot of animals and plants we have to protect. All these species are listed in the Red lists, which distinguish them into three groups:
Endangered are species which number falls quickly and for saving them are special measures necessary. Vulnerable are species which are still enough to survive but their number falls very quickly, too. Rare species can very easily disappear. In the Red list from 1996 there are written 5205 species which need help or protection. But this number grows every year. The giant panda is one of the most endangered animals. This beautiful mammal is very rare because of the output of wood in Chinese forests. Bamboo is the main food for pandas and it is a part of the forest which doesn‘t grow without trees above itself. It is very easy to understand: when people cut the trees, bamboo doesn‘t grow and pandas have no food. They have to move somewhere else, where bamboo still is. But there are almost no areas where pandas can live peacefully. Therefore only about 1000 pandas remain in the wild today. They live in seven separated little areas in China

Earthquake, vibrations produced inside the earth. The vibrations can range from barely noticeable to catastrophically destructive. There are six kinds of shock waves generated in the process. Two are classified as body waves and the other four are surface waves.
The general classes of earthquakes are: tectonic,vulcanic and artificially. The tectonic is the most devastating but scientists find ways to predict them.
The tectonic earthquake is situated in zones where one plate slides past another,for example at the San Andreas fault in California. These eartquakes are more frequent and stronger.In these regions they can cause great loss of life by destroing structures, buildings, bridges and they can also devastating nature.
Seismologists have devised two scales to desribe earthquakes quantitatively. One is the Richter scale-, which measures the motion of the land from the epicenter to focus.The Richter scale is open-ended.The other scale measures the intensity of shaking from 1 to 12.
The strongest earthquakes were in 1906 in San Francisco 8.3-9.2 and in 1964 the Alaskan earthquake 8.4-9.2 richter´s scale, but the biggest one was in Tokyo with the loss of 200 000 lives. It was past but now we can predict the earthquakes and it help´s people in stricken areas.

Huricanes-this name is for migratory tropical cyclones,which originate over oceans in certain regions near the equator.Huricanes in the western Pacific are known as typhoons.Huricanes consist of high-velocity winds blowing circularly around a low-presure centre,called the eye of storm.The diameter of the area affected by winds of destructive force may be 240 km.The strength of huricane is rated from 1 to 5.The mildest category 1, has got winds of 150 km/h.The strongest category,Category 5,has winds that exceed 250 km/h.Huricanes usualy move in path looking like the curve of a parabola.

Floods-when it rains or snows,some of the water is retained in the soil,some is absorbed by vegetation,some eveporates and the rest is called runoff.Floods occur when the soil and vegetation can´t absorb all the water.
Periodic floods occur naturally on many rivers.These floods are often results from heavy rain,sometimes combined with melting snows.It causes the riverbank overflow.A flood that rises and falls rapidly is called flash flood. Floods don´t only damage property and manace the live of people and animals,but have also other effects.Rapid runoff causes soil erosion. Prolonged high floods delay traffic and economic use of lands.Bridges abutments,bank lines,outfalls and other structures are damaged.Financial losses are caused by floods are comounly milions of dollars each year.

Koniec vytlačenej stránky z https://referaty.centrum.sk