My+Work

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1) When people are colour blind, they cannot distinguish between certain colours, especially red and green. (a) Give examples of jobs that may be dangerous if you are red-green colour blind and explain why they are dangerous. (b) Write a short recommendation for a website that enables you to test your colour vision to see if you suffer from colour blindness using patterns.

Colour blindness is the inability to see differences between colours that normal people can differentiate. It is most often caused by genes, but it can also be caused by eye and brain damage. Colour blindness usually does not cause complete inability to see colours. Studies have found that around 7% of males have some level of difficulty in differentiating colours, and that the percentage is much lower among females.

Being colour blind prevents people from engaging in certain occupations, due to difficulties in telling colours apart. This can be a safety hazard, especially in jobs using colour coded signals.

Colour blind people cannot take jobs involving driving vehicles eg. Taxi driver, Bus driver. Traffic lights use red and green signals to tell the drivers whether they should stop or go. As colour blind people often mistake red for green and vice versa, they may get confused about the signals, and this could cause serious traffic accidents. As a taxi or bus driver, they are also responsible for the lives of the passengers, and it would be a serious safety hazard to allow colour blind people to drive.

Also, colour blind people cannot direct traffic as well, eg. Traffic conductors. As mentioned previously, they may get mixed up with the different coloured lights and this can cause car accidents or traffic jams.

Colour blind people cannot be pilots either. Airports also use coloured lights to tell the pilots if they can take off or land the aircraft, and interpreting the lights wrongly would have dire consequences, endangering the lives of all the passengers on the aircraft.

Military jobs are also out of the question for colour blind people. The military uses many different signals, and mixing colours up may change the meaning of the signals completely. Again, a colour blind person in the military may endanger the lives of others, and would be a safety hazard.

Finally, a colour blind person may have serious difficulties with being a fashion designer, an artist or even an interior designer. All these jobs depend on one’s ability to put matching colours together, and when one is colour blind, it is more difficult to match colours up, due to the inability to differentiate colours.

When finding a colour blind test, I think that [] was the best website I looked at. It uses the Ishihara Colour Vision test plates to see if one is colour blind. There are a total of 8 plates, each showing a different number. A normal person would be able to see all the numbers, while a colour blind person might only see some of the numbers, or even none at all. I liked this test because it was extremely fast, taking only about 30 seconds to complete, and it used a well known medical test for colour blindness. Though it was not very in depth, and seeing a doctor would be far more reliable, I think that it is a pretty good resource for a basic test of colour blindness.



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1) Do research on the attempts made by Johann Dobereiner and John Newlands to classify the elements. Write a report on your findings.

Johann Wolfgang Dobereiner was born on December 13 1780 and died on March 24 1849. He is best known for his work on classifying the elements.

When Dobereiner was alive, only a few elements had been discovered, so he did not have a complete periodic table to work with. Dobereiner decided to classify the elements based on their similarities. Since calcium, strontium and barium have similar chemical properties, they were grouped together. This was when he realised that the atomic weight of strontium was halfway between calcium and barium. The same applied to the alkali metals lithium, sodium and potassium as well as the halogens chlorine, bromine and iodine. In 1829, Dobereiner used these results to form the Law of Triads, which stated that the middle element in a triad had an atomic weight which was the average of the other two elements. This led other scientists to find that relationships between chemicals extended to more than triads, and soon elements were added, for example fluorine to the chlorine bromine iodine triad.

John Alexander Reina Newlands was born on 26 December 1837 and died on 18 July 1898. He is known for pioneering the periodic table.

When Newlands was alive, there were a total of 62 known elements, much less as compared today. However, Newlands was the first person to come up with the idea of classfying the elements based on their atomic weight. He continued where Dobereiner left off, and in 1865, Newlands produced the Law of Octaves, which stated that chemical properties repeated every 8 elements. Newlands drew his own periodic table, and it was read in the opposite direction as compared to the modern periodic table. However, his table was very incomplete and it allowed Newlands to predict the existence of new elements, for example germanium. Newlands periodic table was extremely similar to the modern one, however at the time it was mocked by the Society of Chemists and his work was not published.