Rainmaker with his Head in the Clouds - Test 4

C2 Proficiency · Gapped Text · Proficiency Testbuilder, 4th Edition, Mark Harrison, Macmillan

You are going to read a newspaper article. Seven paragraphs have been removed from the article. Choose from the paragraphs A–H the one which fits each gap (1–7). There is one extra paragraph which you do not need to use.

Rainmaker with his Head in the Clouds

Critics dismissed Graeme Mather's attempts to make clouds rain. But now recent experiments appear to have vindicated him. Anjana Ahuya reports.

Dr Mather refused to be daunted by this image. After all, the principle seemed perfectly plausible. Water droplets are swept up to the top of the clouds on updrafts, where they become supercooled (i.e., although the temperature is below freezing, the water remains liquid). When a supercooled droplet collides with an ice crystal, it freezes on contact and sticks. Successive collisions cause each ice crystal to accumulate more water droplets; the crystals grow until they become too heavy to remain suspended in the atmosphere. As the crystals fall through the cloud, they become raindrops. The ice crystals therefore act as frames to 'grow' raindrops.

Dr Mather unfortunately will not be involved in the debate about such matters. He died aged 63, shortly before the documentary was completed. It will ensure that this smooth-talking maverick is given the recognition he deserves.

He and a colleague decided to collect a last batch of data when they flew into a tiny but ferocious storm. That storm, Dr Mather says in the film, changed his life. Huge droplets were spattering on the tiny plane's windscreen. No such storm had been forecast. Back on the ground, they discovered the storm was located directly above a paper mill.

A trial in Mexico has been running for two years, and the signs are promising. 'We were sufficiently encouraged in the first year to continue the seeding research. But the results are preliminary, because we have only a very small sample of clouds at the moment. We need to work over two more summers to reach a proper conclusion.'

He arranged to fly to South Africa 'with the full intention of explaining what was wrong with the experiment'. Instead, he came back convinced that Dr Mather was on to something. He is now running two experiments, one in Arizona and one in northern Mexico to try to verify the South African results. The experiments use potassium chloride, which is similar to table salt (sodium chloride) and, it is claimed, non-polluting.

The scientific community remained sniffy in the face of this apparent proof. Foremost among the sceptics was Dr William Cooper, of the United States National Centre for Atmospheric Research (NCAR). Dr Cooper, regarded as one of the world's finest cloud scientists, saw Dr Mather present his astonishing claims at a cloud physics conference in Montreal.

They involved weather experts firing rockets into clouds to stop them producing hail, which damages crops. The clouds, it was hoped, would dissolve into a harmless shower.

The desire to do so led him to set up a project in South Africa, which was ultimately to convince him that it was possible. As the programme reveals, experiments around the world appear to prove his faith was justified.

Dr Graeme Mather lived his life with his head in the clouds, as a documentary film to be shown this week shows. Against the advice of almost everybody else in the meteorological community, the Canadian scientist devoted his professional life to trying to make clouds rain.

Before Dr Mather became involved, the science of weather modification had already claimed many reputations. The idea that clouds could be manipulated first circulated in the 1940s, and efforts gathered pace soon after the Second World War.

However, the entire discipline fell into disrepute when commercial companies hijacked the idea, took it around the world, and then failed to deliver on their promises. Cloud-seeding, as the process was known, became the preserve of crackpots and charlatans.

Scientists theorised that if they could inject the cloud with similarly shaped crystals, these imposter crystals would also act as frames around which droplets would clump. The cloud would then be tricked into raining. Silver iodide, whose crystals resemble those of ice, seemed the best bet. Sadly, none of the experiments, including Dr Mather's, which had been going for more than five years, seemed to work. Dr Mather was about to admit defeat when serendipity intervened.

Dr Mather was convinced that something that the place was spewing into the atmosphere was encouraging the downpour. Subsequent experiments confirmed that hygroscopic salts pouring into the sky from there were responsible. Hygroscopic salts attract water – once in the atmosphere, the particles act as magnets around which raindrops can form.

He was wary; Dr Mather was known to be a smooth-talking salesman. 'He was charming and charismatic, and many scientists don't trust that,' he says. 'He was also not well-published because he had been working in the commercial sector. Overall, he was regarded as a maverick. On that occasion, he presented results that I was convinced were impossible. Yet the statistical evidence was overwhelming, which I couldn't understand.'

'If those findings can be reproduced there, it will be the most exciting thing to have happened in the field for 20 years. It will be remarkable because some of the results are not scientifically explainable.' He adds, however, that scientists must exercise caution because cloud-seeding is still mired in controversy. He also points out that, with water being such a precious resource, success will push the research into the political arena.

Dr Cooper says: 'With the paper mill, he saw something that other people wouldn't have seen. I am still uncomfortable with his idea because it throws up major puzzles in cloud physics. But if Dr Mather was right, it will demonstrate that humans can change clouds in ways that were once thought impossible.'

Dr Graeme Mather lived his life with his head in the clouds, as a documentary film to be shown this week shows. Against the advice of almost everybody else in the meteorological community, the Canadian scientist devoted his professional life to trying to make clouds rain. ___ Before Dr Mather became involved, the science of weather modification had already claimed many reputations. The idea that clouds could be manipulated first circulated in the 1940s, and efforts gathered pace soon after the Second War World War. ___ However, the entire discipline fell into disrepute when commercial companies hijacked the idea, took it around the world, and then failed to deliver on their promises. Cloud-seeding, as the process was known, became the preserve of crackpots and charlatans. ___ Scientists theorised that if they could inject the cloud with similarly shaped crystals, these imposter crystals would also act as frames around which droplets would clump. The cloud would then be tricked into raining. Silver iodide, whose crystals resemble those of ice, seemed the best bet. Sadly, none of the experiments, including Dr Mather's, which had been going for more than five years, seemed to work. Dr Mather was about to admit defeat when serendipity intervened. ___ Dr Mather was convinced that something that the place was spewing into the atmosphere was encouraging the downpour. Subsequent experiments confirmed that hygroscopic salts pouring into the sky from there were responsible. Hygroscopic salts attract water – once in the atmosphere, the particles act as magnets around which raindrops can form. ___ He was wary; Dr Mather was known to be a smooth-talking salesman. 'He was charming and charismatic, and many scientists don't trust that,' he says. 'He was also not well-published because he had been working in the commercial sector. Overall, he was regarded as a maverick. On that occasion, he presented results that I was convinced were impossible. Yet the statistical evidence was overwhelming, which I couldn't understand.' ___ 'If those findings can be reproduced there, it will be the most exciting thing to have happened in the field for 20 years. It will be remarkable because some of the results are not scientifically explainable.' He adds, however, that scientists must exercise caution because cloud-seeding is still mired in controversy. He also points out that, with water being such a precious resource, success will push the research into the political arena. ___ Dr Cooper says: 'With the paper mill, he saw something that other people wouldn't have seen. I am still uncomfortable with his idea because it throws up major puzzles in cloud physics. But if Dr Mather was right, it will demonstrate that humans can change clouds in ways that were once thought impossible.'

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