Luyện tập viết IELTS Writing task 2

I work for the National Weather Service and as part of your course on weather patterns, I've been asked to talk to you about how we predict the weather. We're so used to switching on our TVs and getting an up-to-date weather forecast at any time of day or night that we probably forget that this level of sophistication has only been achieved in the last few decades and weather forecasting is actually an ancient art. So I want to start by looking back into history.

 The earliest weather forecasts appeared in the 1500s in almanacs, which were lists of information produced every year. (31) Their predictions relied heavily on making links between the weather and where the planets were in the sky on certain days. In addition, predictions were often based on information like if the fourth night after a new moon was clear, good weather was expected to follow.

But once basic weather instruments were invented, things slowly started to change. (32) In the mid-fifteenth century, a man called Nicholas Cusa, a German mathematician, designed a hygrometer which told people how much humidity there was in the air. To do this, Cusa put some sheep's wool on a set of scales and then monitored the change in the wool's weight according to the air conditions. A piece of equipment we all know and use is the thermometer. (33) Changes in temperature couldn't really be measured until the Italian Galileo Galilei invented his thermometer in 1593. It wasn't like a modern-day thermometer because it had water inside it instead of mercury. In fact, it wasn't until 1714 that Gabriel Fahrenheit invented the first mercury thermometer. In 1643 another Italian called Evangelista Torricelli invented the first barometer which measured atmospheric pressure. This was another big step forward in more accurate weather predicting.

As time went on, during the seventeenth, eighteenth and nineteenth centuries, all these meteorological instruments were improved and developed and people in different countries began to record measurements relating to their local weather. However, (34) in those days it was very difficult to send records from one part of the world to another so it wasn't possible for them to share their information until the electric telegraph became more widespread. This meant that weather observations could be sent on a regular basis to and from different countries. By the 1860s, therefore, weather forecasts were becoming more common and accurate because they were based on observations taken at the same time over a wide area. (35) In 1863, France started publishing weather maps each day. This hadn't been done before, and other nations soon followed. So that was the start of national weather forecasting and I'll now tell you how we at the National Weather Centre get the information we need to produce a forecast.

Even today, one of the most important methods we use is observations which tell us what the weather is doing right now. Observation reports are sent automatically from equipment at a number of weather stations in different parts of the country, (36) They are nearly all based at airports although a few are in urban centres. The equipment senses temperature, humidity, pressure and wind speed direction.

Meteorologists also rely really heavily on satellites which send images to our computer screens. What we see on our screens is bright colours. (37) Orange represents dry air and bright blue shows moisture levels in the atmosphere. The satellites are located 22,000 miles above the surface of the Earth and it's amazing that despite that distance (38) it's possible for us to make out an individual cloud and follow it as it moves across the landscape.

In addition to collecting data from the ground, we need to know what's happening in the upper levels of the atmosphere. So a couple of times a day from many sites across the country, we send radiosondes into the air. (39) A radiosonde is a box containing a package of equipment and it hangs from a balloon which is filled. with gas. Data is transmitted back to the weather station. Finally, radar. (40) This was first used over 150 years ago and still. is. New advances are being made all the time and it is one method for detecting and monitoring the progress of hurricanes, Crucial information is shown by different colours representing speed and direction. Radar is also used by aircraft, of course. All this information from different sources is put into computer models which are like massive computer programs. Sometimes they all give us the same story and sometimes we have to use our own experience to decide which is showing the most accurate forecast which we then pass on to you. So I hope next time you watch the weather forecast, you'll think about how we meteorologists spend our time. And maybe I've persuaded some of you to study meteorology in more depth.

Good morning, everybody. Today I’m going to talk about one of the most terrible wars of the twentieth century. Although it took place mainly in Europe, it involved countries from all over the world. I’m talking, of course, about the First World War, from 1914 to 1918, which resulted in the death of about ten million military personnel. Despite the enormous human cost, the war did have some positive consequences. In fact, it was precisely because of the nature and scale of the horrors of the battlefield that many important medical advances were made, as new equipment and techniques had to be developed quickly to cope with the huge number of injuries.

As I said, the scale of the First World War was huge. New weapons were used that were designed to kill on an industrial scale, such as machine guns, tanks and poison gases. These produced brutal results: many deaths and about twice as many injuries. Those injured suffered very severe wounds and this pushed the medical establishment to build on recent discoveries and to come up with solutions for the new problems faced by doctors. I’m going to tell you about a few of these.

You probably know that X-rays were discovered in 1895, and were developed for limited medical use in the following year. But their use became much more widespread during the war, when they helped detect fragments of bombs and bullets buried in tissue. They allowed doctors to extract these elements, which would otherwise have caused serious infections. Stretchers for carrying injured people had also been in use before the war, but the development of rescuing the wounded from the battlefield, by sending in stretcher-bearers to bring them back as quickly as possible, was completely new. The modern concept of a paramedic, who is able to apply first aid in the field, also comes from this time.

Blood transfusion was in its early days at the time of the Great War. It was done person-to-person, that is, with a tube transferring blood from one person to another. This was extremely impractical and carried a very high risk. The rigours of the war demanded a better solution and by 1917 indirect transfusion had been developed. It was possible to store blood on ice for up to 26 days and deal much better with battle injuries. For many, this was the most significant medical breakthrough of the war.

Teacher: Good afternoon. So we’re fast approaching exam season and I can already see a lot of tired faces here in front of me. Well, today we are lucky enough to have Professor Manson from the University of Denton talk to us about how sleep can help us pass those all-important exams. So without any further ado, I’d like you to give a big round of applause and stay wide awake for Professor Denton.

Professor: Good afternoon. Looking around this room now takes me back to when I was your age and life seemed to be a never-ending chain of exams and assignments. At that time, organisation was not my forte and too often I found myself up all hours of the night before an exam cramming every last piece of information I could in an attempt to remember something. Does that sound familiar to any of you? Can I just see a show of hands how many of you this term have had no more than 3 or 4 hours' sleep before an exam? OK, so that’s a clear majority and it has to be said that last-minute revision can do wonders for the short-term memory, but what is, in fact, even more beneficial is a good night’s sleep.

So, I’d like to explain to you now, especially you all-night crammers, the link between sleep and memory and how a good night’s kip can improve your exam results. Now, could everyone take a minute to work out, on average, how many hours' sleep they get every night. Can I see a show of hands for more than 10 hours? OK, none of you, how about between 8 and 10 hours? A handful of you. OK, so what about between 6 and 8 hours? Right, that’s a popular option. And any of you fewer than 6 hours? Mmm … OK, so you’re the guys we most need to worry about.

According to the National Sleep Foundation in Washington, newborn babies need anything between 14 and 17 hours' sleep and this amount gradually decreases the older we get until as adults we need around 7 or 8 hours sleep, but … you’ll be interested to know that the 14 to 17 age group should be aiming for 8 to 10 hours' sleep a night. So you can already see that most of us are not getting enough sleep, and this is something we need to think about.

Sleep is essential. The human body simply can’t survive without it. End of story. While we’re asleep, the body checks that all our vital functions such as growth, circulatory systems and our immune system are in good working order. And while we’re snoring away, our brains are very active restructuring information we’ve collected during the day and consolidating memories.

So let me explain memory consolidation. Memory consolidation is what happens when information is moved from our short-term memory to our long-term memory with the help of a major part of the brain called the hippocampus. This is it folks … this is the BIG moment when all of those facts and figures that you have crammed into your short-term memory are processed and consolidated in your long-term memory.

However, as you’re probably aware, we don’t always remember everything. One reason we remember certain things better than others relates to the environment or conditions we were in when we originally made the memories. What experts have discovered is, the more emotions that are activated when we make a memory, the more likely we are to consolidate that memory. So, for example, the more interesting or fun you find a biology lesson, the more chance there is of you remembering information from it … OK, teachers? And not only that … we actually need to review information again and again after certain periods of time to help the consolidation process, which is why well-planned exam revision timetables are far more effective in the long term than short-term cramming the night before.