Cathode Ray Tube free essay sample

Do you like watching television? I love it. I do not know what would I do if televisions did not exist. It is interesting, in several years, they have become a huge part of our lives, our indispensables. J. J. Thomson was inspired by some scientists and he provided us the opportunity of having televisions in our lives. Also other scientists improved his thoughts and experiments which leaded to the invention of the television afterwards. It is not that simple of course. Let’s look at the backstage By the beginning of the 20th century, there were some problems that had not been solved. The main problem was; not being able to understand the structure of matter. If the structure of the matter could be solved, all the other problems could be solved too. That’s why the major part of the scientists were trying to understand the details about the matter. First atomic theory, which was based on experimental observations, was produced by John Dalton in 1808. His theory was consisted of the following: * all matter is made up of atoms, * atoms are indivisible and can neither be created nor destroyed, all the atoms of an element are identical * compounds are formed by the chemical combination of atoms in small whole number ratios. Dalton called these groups as â€Å"compound atoms† which we call â€Å"molecules† today. Today, we know that atoms are divisible and that all atoms are not the same, there are isotopes in the nature. So, John Dalton was wrong in some ways. Although some parts of his theory were wrong, we can say that Dalton was successful since he could explain the structure of matter for the first time. By this theory, he also helped and inspired J. J. Thomson to do a brilliant experiment which in this case concerns us deeply, since it laid the groundwork for invention of television. Keeping Dalton’s atomic theory in mind, in 1897, J. J. Thomson made an experiment which helped the scientists to learn more about atom and improve the scientific information. The experiment was on the rays that were produced by making a cathode ray tube. â€Å"Cathode ray tube is also known as a television picture tube, it is also used for visual display in oscilloscopes and radar systems. On the neck of the tube, there is an electron gun that ends electrons that pass through a control grid a focusing anode (-) . A second anode speeds the electrons as the beam passes. After the beam passes through the second anode, it is deflected in one of two ways: electrostatically or magnetically. Magnetic deflection is used in radar display tubes and most of the television display tubes. The cathode ray tube screen is coated with a phosphor chemical. The coating converts the energy of the electron beam into visible light and presents a visual display. † 1 If we summarize, cathode ray tube is a type of vacuum tube that uses electrons to produce an image on a screen. By using this kind of cathode ray tube, J. J. Thomson discovered the negative charges in the atom, and he called them in his own way, but as a matter of fact he has found the â€Å"electrons†. George Stoney had thought the existance of them in 1891, but he was unable to prove. Then, Thomson thought that; as electrons have negative charges, but atoms are neutral, there should be some positive charges somewhere in the atom. Also, as electrons are much smaller and lighter than atoms, those positive charges should be much heavier than electrons. Therefore, Thomson made an atom model that seems like a plum pudding. Also, by finding this, he has found H+ ion which helped him to realise that atom could be divided. This showed that, John Dalton was wrong by saying that atom could not be divided into small pieces. This also proved that all atoms were not the same and John Dalton was wrong again. J. J. Thomson has won the 1906 Nobel Prize for his â€Å"Cathode Ray Tube Experiment†. Thomson was wrong in some parts like Dalton. Thomson thought that â€Å"electrons move randomly in the atom,† however today we know that they are on the orbitals. Despite Thomson’s success in so many ways, there were some thoughts left unproved. These thoughts were proved by some experiments. In 1906, R. A. Milikan measured the charges of electrons and as a result, he proved Thomson’s thought: electrons covered just a little part of the atom (plum pudding model). Afterwards, Ernest Rutherford made an experiment called â€Å"Gold Foil Experiment† in 1911. He sent alfa rays onto the gold atoms, and he saw that the rays were coming back. So, he realised that there were some positive charges in the centre, and he called these positive charges, which Thomson thought of their existance, â€Å"protons†. By this way, Rutherford has found that the nucleus of atoms consists of protons. However, there was a question which was not answered: why did not the electrons fall onto the nucleus by the attraction of protons? In 1913, a student of Rutherford called Neils Bohr, thought that electrons had certain energies (quantum), and that they were moving. By the year 1922, Bohr and Arnold Sommerfeld has explained that the first shell had 2, and the second one had 8 electrons. As one shell gets full, the electrons locate into the other shell. Also, the chemical properties were explained according to the last shell. The elements in which the last shell is full, do not get into reactions, and the others give or take electrons to make their last shells full. The periodic table was arranged by the elements’ mass numbers, but this time it was rearranged according to the atom numbers. However, there was occured another question that was not answered: why are there 2 electrons in the first shell, and 8 electrons in the second shell? As nothing has an end, science doesn’t have too. Each day some new things are added to life. Chemistry is the same. Starting from early years until today, chemistry is trying to be solved by all the scientist. Although these successful scientists above have accomplished so important things, there are still some things unknown that are going to be certainly solved in the future. Over a hundred years ago today, Thomson made the â€Å"Cathode Ray Tube Experiment†. With the huge help of his experiment, science has extremely improved. After he accomplished the experiment, with the help of the data that he collected and with the things he had discovered, scientists made other discoveries that are very useful today. Another thing is, we can watch television now by the help of cathode ray tubes. Televisions have become our indispensables. We almost arranged our lives according to them. Now, we can learn everything about the world from televisions, we can watch films or programmes that entertains us, we can even order food or pay the bills from televisions! It is really amazing. I think we should thank