englischlehrer.de  
VARIOUS TEXTS: ENVIRONMENT: LEADED PETROL AND CFCs

As rumours circulated about the dangers of the new product, ethyl's1 ebullient2 inventor, Thomas Midgley, decided to hold a demonstration for reporters to allay3 their concerns. As he chatted away about the company's commitment to safety, he poured tetraethyl lead over his hands, then held a beaker4 of it to his nose for sixty seconds, claiming all the while that he could repeat the procedure daily without harm. In fact, Midgley knew only too well the perils of lead poisoning: he had himself been made seriously ill from overexposure a few months earlier and now, except when reassuring journalists, never went near the stuff if he could help it.

Buoyed by the success of leaded petrol, Midgley now turned to another technological problem of the age. Refrigerators in the 1920s were often appallingly risky because they used insidious5 and dangerous gases that sometimes seeped out. One leak from a refrigerator at a hospital in Cleveland, Ohio, in 1929 killed more than a hundred people. Midgley set out to create a gas that was stable, non-flammable, noncorrosive and safe to breathe. With an instinct for the regrettable that was almost uncanny6, he invented chlorofluorocarbons7, or CFCs.

Seldom has an industrial product been more swiftly or unfortunately embraced. CFCs went into production in the early 1930s and found a thousand applications in everything from car air-conditioners to deodorant sprays before it was noticed, half a century later, that they were devouring the ozone in the stratosphere. As you will be aware, this was not a good thing.

Ozone is a form of oxygen in which each molecule bears three atoms of oxygen instead of the normal two. It is a bit of a chemical oddity in that at ground level it is a pollutant, while way up in the stratosphere it is beneficial since it soaks up dangerous ultraviolet radiation. Beneficial ozone is not terribly abundant, however. lf it were distributed evenly throughout the stratosphere, it would form a layer just 2 millimetres or so thick. That is why it is so easily disturbed.

Chlorofluorocarbons are also not very abundant - they constitute only about one part per billion of the atmosphere as a whole - but they are extravagantly destructive. A single kilogram of CFCs can capture and annihilate 70,000 kilograms of atmospheric ozone. CFCs also hang around for a long time - about a century on average - wreaking havoc8 all the while. And they are great heat sponges. A single CFC molecule is about ten thousand times more efficient at exacerbating9 greenhouse effects than a molecule of carbon dioxide - and carbon dioxide is of course no slouch10 itself as a greenhouse gas. In short, chlorofluorocarbons may ultimately prove, to be just about the worst invention of the twentieth century.
461 words

Source: A Short History of Nearly Everything by Bill Bryson, Black Swan paperback 2004, GB, pp. 195/96


Annotations:
1. (tetra-)ethyl - "Ethyl" brand leaded gasoline versus ethyl alcohol -- which was the best anti-knock additive for gasoline? Three grams of tetra ethyl lead and 15 percent ethyl alcohol both improved a fuel's power. One was cheap, but it was a well known poison. The other was a clean, renewable fuel that helped farmers and kept nations independent of political oil pressures. Dozens of countries were already using ethyl alcohol fuels.
2. ebullient - überschwänglich
3. to allay - beschwichtigen
4. beaker - Messbecher
5. insidious - heimtückisch
6. uncanny - unheimlich
7. chlorofluorocarbons (=CfCs) - FCKW
8. to wreak havoc - verheerenden Schaden anrichten
9. to exacerbate - verschlimmern
10. slouch - Pfusch (-arbeit)


Assignments:
1. Why did Midgley claim that tetraethyl didn't cause any harm to human beings?
2. What made Midgley invent CFCs?
3. Why is ozone beneficial and dangerous at the same time?
4. Why are CFCs so harmful to the ozone layer?
5. What text type is this?



amazon.de A Short History of Nearly Everything
by
Bill Bryson
amazon.de


© 1997-2017 englischlehrer.de × Alle Rechte vorbehalten. × Ausgewiesene Marken gehören ihren jeweiligen Eigentümern.
englischlehrer.de übernimmt keine Haftung für den Inhalt verlinkter externer Internetseiten.
2.575 (+4.321)pi × search powered by uCHOOSE