 |
| Sir J. J. Thomson |
From the time of the Greeks, philosophers had the idea that all matter was made up of tiny, indivisible particles called atoms. That is, the last state that can be obtained by breaking down any substance is the atom. But at present, our race to break is not stuck to the atom.
By breaking down the atom, we have brought out the electron, the nuclei. However, the fact that the atom can be divisible, that is, the atom is also made up of smaller particles, we know that only 120! The first basic element in the formation of atoms is the electron! We know that electrons are negatively charged particles, which are present in all ordinary matter in the universe!
The electron is an elementary particle that was first discovered by scientist Sir Joseph John Thomson in 1897. He made the discovery while researching cathode ray tubes at the Cavendish Laboratory at the University of Cambridge. A cathode-ray tube is a completely closed glass cylinder in which two electrodes are separated by a vacuum and contains a small amount of low-pressure gas. When the voltage difference between the two conductors is applied, the gases near the negative electrode or cathode glow like an aura. One of a kind from the cathode this aura is created in the tube for the emitted ray (particle emission)! This ray is called cathode ray. Through subsequent experiments to learn about the nature of these rays, Thomson proved that the negative charge from a ray cannot be separated by magnetism; However, the rays can be scattered by the electric field. In order to gain an idea of the origin of the electron and its components, Thomson had to perform three experiments:
First:
This test was very similar to the one conducted by Jean Perrin in 1895. Thomson made a cathode ray tube by a pair of metal cylinders with a narrow gap between them. These two cylinders were again connected to an electrometer so that the electric charge could be stored and measured. Perrin observed that the cathode ray accumulates an electric charge. Thomson wanted to see if the charge could be separated from the beam by bending the rays with a magnet. He saw that when the rays entered the narrow gap of the cylinder, an excess of negative charge was observed in the electrometer. When the rays are bent, the amount of negative charge in the meter is not so much, because the rays do not get a chance to enter the gap. From this, it is clear that cathode ray and negative charge cannot be separated in any way.
This test was very similar to the one conducted by Jean Perrin in 1895. Thomson made a cathode ray tube by a pair of metal cylinders with a narrow gap between them. These two cylinders were again connected to an electrometer so that the electric charge could be stored and measured. Perrin observed that the cathode ray accumulates an electric charge. Thomson wanted to see if the charge could be separated from the beam by bending the rays with a magnet. He saw that when the rays entered the narrow gap of the cylinder, an excess of negative charge was observed in the electrometer. When the rays are bent, the amount of negative charge in the meter is not so much, because the rays do not get a chance to enter the gap. From this, it is clear that cathode ray and negative charge cannot be separated in any way.
Second:
Physicists have failed to bend the cathode ray with the help of electric fields. This time Thomson thought of a new experiment. An ionized particle must bend if it is affected by an electric field, but it will not bend if it is surrounded by a conductor. He suspects that the gas inside the tube has become electrically conductive due to the cathode ray in special circumstances. With great difficulty to prove this idea, he was able to make a tube an almost pure void. This time the test showed that the cathode ray was being bent by the electric field. From these two tests, Thomson came to the conclusion,
Physicists have failed to bend the cathode ray with the help of electric fields. This time Thomson thought of a new experiment. An ionized particle must bend if it is affected by an electric field, but it will not bend if it is surrounded by a conductor. He suspects that the gas inside the tube has become electrically conductive due to the cathode ray in special circumstances. With great difficulty to prove this idea, he was able to make a tube an almost pure void. This time the test showed that the cathode ray was being bent by the electric field. From these two tests, Thomson came to the conclusion,
"I can in no way escape the conclusion that the cathode ray is the charge of a negative charge carried by a particle of matter ..... What are these particles?? "
Third:
The subject of Thomson's third experiment was to explore the basic properties of particles. Although he was not able to direct the mass or charge of any such particle, he was able to measure by magnetism how much these rays bend and how much energy they contain. With these data, he finds a ratio between the mass (m) of a particle and its charge (e). That is, e / m = 1.8 10-11 coulombs / kg.
The subject of Thomson's third experiment was to explore the basic properties of particles. Although he was not able to direct the mass or charge of any such particle, he was able to measure by magnetism how much these rays bend and how much energy they contain. With these data, he finds a ratio between the mass (m) of a particle and its charge (e). That is, e / m = 1.8 10-11 coulombs / kg.
To be sure, he collected the data by performing tests on many types of pipes and gases. Quite surprising results are obtained from this ratio; Its value is more than eighteen times smaller than that of ionized hydrogen! Thomson is fairly sure about the discovery of electrons! However, long before the discovery of the electron, the emission of the first cathode ray was somewhat similar to the "emission of rays from the heated wire".
Elektron is the Greek word for an evergreen tree. Which attracts light objects such as hair, small pieces of paper when rubbed on any cloth! Electricity from this electron, naming electronics! After the discovery of the electron, Thomson developed a model called the plum-pudding model. Inside the pudding, raisins are scattered in an atom, just as electrons are scattered in a positively distributed positive charge. Indigenously this model can be called the watermelon model. If the juicy part of the watermelon is considered a positive charge and if the watermelon seed is considered a negatively charged electron, then the scattering of its seeds in the juicy part of the watermelon can be compared to the Thomson atomic model. It is also called Thomson's atomic model!
We know that electrons are lepton classified particles according to the standard model! Electrons also behave like waves. That is, particle-wave duality! Thomson won the Nobel Prize in 1906 for his discovery of the electron!
