" LOOKING IN THE TELESCOPE"

A story is told that around 400 years ago some children were fooling around in an eye glass shop. They noticed that when they placed lenses one on top of the other, they were able to see a considerable distance. They played around with the concept for a while, experimenting with what happened when they varied the distance between the lenses. Hans Lippershey, the Dutch lens maker who eventually applied for the first telescope patent, credits children as having been his motivation for the invention of the first telescope.

The first telescopes built in the early 1600s were very primitive inventions allowing the user to see around 3-times further than the naked eye. It was not too long however, until Italian astronomer Galileo heard about the invention ‘that through use of correctly-positioned lenses, allowed people to see things a long way away’. The tools used in the manufacturing of the first refracting telescope was all Galileo needed to know and within 24 hours he had developed a better one. In fact, the process of improvements Galileo made on Lippershey’s telescope were quite dramatic. Whereas the original version had a magnification of 3, the new telescope had a magnification of around 30. Galileo achieved these extraordinary results by figuring out the combination of the positions of the lenses and also by making his own lenses which were of better quality. Although he originally thought they were stars, the better quality lenses – and some scientific analysis – enabled him to eventually use his telescopes to see the moons of Jupiter. Galileo’s refracting telescopes – so-called due to the way they handled the light that passed through them – were the standard at that time.

Some 70 years later, British scientist Isaac Newton, explored the way a prism refracts ¹ white light into an array of colors. He recognised that a lens was a circular prism and that the separation of colors limited the effectiveness of the telescopes in use at the time. Newton created a Reflective Telescope, one that used a dish-shaped or parabolic mirror to collect light and concentrate the image before it was visible in the eyepiece. Thus, lenses used for magnification in telescopes were replaced by mirrors. Mirrors have since been the standard for telescopes. In fact, according to telescope researcher Dr. Carl Addams, the basic designs of telescopes have not changed much in the last 100 years. What has changed however, is the way technology has been used to improve them. For example, the larger telescopes in the world today are around 10 metres in diameter and the mirrors placed within them are so finely polished that even at the microscopic level there are no scratches or bumps on them at all. To achieve such a flawless surface requires a very expensive process that operates with the utmost precision.

¹: The separation or change of direction of a ray of light when passed through a glass of water.

The mid 1700s, saw the discovery and production of the Achromatic telescope. This type of telescope differed from previous ones in the way it handled the different wavelengths of light. The first person who succeeded in making achromatic refracting telescopes seems to have been the Englishman, Chester Moore Hall. The telescope design used two pieces of special optical glass known as crown and flint Each side of each piece was ground and polished and then the two pieces were assembled together. Achromatic lenses bring two wavelengths – typically red and blue – into focus in the same plane. Makers of achromatic telescopes had difficulty locating disks of flint glass of suitable purity needed to construct them. In the late 1700s, prizes were offered by the French Academy of Sciences for any chemist or glass-manufacturer that could create perfect discs of optical flint glass however, no one was able to provide a large disk of suitable purity and clarity.

Currently the largest telescopes are around eight to ten metres in size. These extremely expensive and sophisticated pieces of equipment are located primarily throughout Europe and America. Dr Addams believes that the telescopes of the future will be a gigantic improvement in what is currently considered state-of-the-art. Telescopes that are 20 or 30 metres in diameter are currently being planned, and there has been a suggestion put forward by a European firm that they would like to build a 100-metre telescope. Says Addams, ‘The quality of the glass needed to build a 100 meter telescope is like building a lens the size of a football field and having the largest bump in that football field being a ten-thousandth of a human hair’. The engineering and technology required to build such a flawless reflective surface is most impressive.

Choose the correct letter, A, B, C or D.

Write the correct letter in boxes 1-5

1- According to the writer, the first telescope was

6- ............ The first telescopes made.

" The intense rate of change in the world"

A. The intense rate of change in the world gives rise to numerous new products – many of them electronic. What is brand new and state-of-the-art one month is quickly relegated to old model’ status the next. Within the world of computing, this frenetic pace of change has led to millions of out-dated, worthless products. Keystone, an American-based research company reported. In 2005, one computer became obsolete for every new one introduced in die market. By the year 2010, experts estimate that in the USA there will be over 500 million obsolete computers. Most of these computers will be destined for landfills, incinerators or hazardous waste exports.’ Old, outdated keyboards, monitors and hard drives all combine to produce what is now widely known as ‘e-waste’ and the way to appropriately dispose of them is proving to be a challenge.

B. Most computers are a complicated assembly of hundreds of different materials, many of which are highly toxic. Most computer users are unaware that these toxic metals, acids, plastics and other substances have been shown to be the cause of various blood diseases and cancers. Amongst workers involved in the recycling of computer products, there has been a proliferation of blood diseases. Printed circuit boards for example, contain heavy metals such as antimony, silver, chromium, zinc, lead, tin and copper. Environmentalist Kieran Shaw estimates there is hardly any other product for which the sum of the environmental impacts of raw material, extraction, industrial refining and production, use and disposal is so extensive as for printed circuit boards.

C. Workers involved in the disposal of computers via incineration are themselves being exposed to significantly high levels of toxicity. Copper, for example, is a catalyst in the release of harmful chemicals when exposed to the high tempera lures of incineration. In US and Canadian environments, incineration is one of the greatest sources of heavy metal contamination of the atmosphere. Unfortunately, another form of incineration, smelting, can present dangers similar to incineration. Concerns have been expressed that the Noranda .Smelter in Quebec, Canada is producing atmospheric pollutants from the residual presence of plastics in the e-scrap.

D. In an effort to explore other alternatives, landfills have been tried, Studies have Shown however, that even the best landfills are not completely safe. In feet the shortcomings of dealing with waste via modern landfills are well documented. The main ‘offender’ in the area of metal leaching is mercury. In varying degrees, mercury escapes or leaches from certain electronic devices such as circuit breakers, condensers and computer circuit boards into the soil. According to Phil Stevenson, managing director of CleanCo a recycling plant in the UK, ‘Everyone knows that landfills leak – it has become common knowledge. Even the best, state-of-the-art landfills are not completely tight throughout their lifetimes, to one degree or another, a certain amount of chemical and metal leaching occurs. The situation is far worse for older or less stringent dump sites. If uncontrolled fires are allowed to burn through these landfill areas, other toxic chemicals such as lead and cadmium are released.

E. An overwhelming majority of the world’s hazardous e-waste is generated by the industrialised market economies. Because labour costs are cheap and government regulations in some countries are decidedly lax, the exporting of e-waste has been practiced as another method to deal with its disposal. In the USA for example, Datatek, a research company, estimated that it was 12 times cheaper to ship old computer monitors to China than it was to recycle them. Data on the prevalence of this activity is scarce due to past bad publicity and dealers of e-scrap not bothering to determine the final destination of the products they sell. In 1989 the world community established the Basel Convention on the Transboundary Movement of Hazardous Waste for final Disposal to stop the industrialised nations of the OECD from dumping their waste on and in less-developed countries.

F. Europe has taken the lead on e-waste management by requiring governments to implement laws controlling the production and disposal of electrical products. The European Union (EL) lias drafted legislation on Waste from Electrical and Electronic Equipment (the WE EE Directive) based on a concept known as Extended Producer Responsibility (EFR). Essentially, EFR places the responsibility’ of the production and disposal squarely on the shoulders of the producers of electronic products, it requires that producers consider carefully the environmental impact of the products they bring to the marketplace. The aim of EPR is to encourage producers of electrical equipment to prevent pollution and reduce resource and energy use at each stage of the product file cycle. The lead in Europe has been necessary’ because WERE is about three times higher than the growth of any other municipal waste streams.

G. WEE legislation will phase-out the use of toxic substances such as mercury, cadmium and lead in electronic and electrical goods by the year 2008. It will require producers of electrical equipment to be responsible financially for the collection, recycling and disposal of their products. It has stipulated that products containing any lead, mercury, cadmium and other toxic substances must not be incinerated. It encourages producers to integrate an increasing quantity of recycled material in any new products they produce. In fact, between 70% and 90% by weight of all collected equipment must be recycled or re-used. These directives will go a long way toward improving the e-waste problem in Europe and other governments of the world should look seriously at implementation of some or all of the legislation.

Choose the correct heading for each paragraph from the list of headings below.

Write the correct number, i-xi, in boxes 14-20

14- ................ Paragraph A