Rutherford's experience in the scattering of alpha particles (briefly)

Ernest Rutherford is one of the founders of the fundamental doctrine of the internal structure of the atom. A scientist was born in England, in a family of emigrants from Scotland. Rutherford was the fourth child in his family, while being the most talented. He made a special contribution to the theory of the structure of the atom.

Initial ideas about the structure of the atom

It should be noted that before the famous Rutherford experiment on the scattering of alpha particles was carried out, the idea of the structure of the atom that was at that time was the Thompson model. This scientist was sure that the positive charge uniformly filled the entire volume of the atom entirely. Negatively charged electrons, thought Thompson, were as if impregnated into it.

Prerequisites for scientific revolution

After graduation, Rutherford, as the most talented student, received a 50-pound grant for further study. Thanks to this, he managed to go to college in New Zealand. Further, the young scientist takes examinations at Canterbury University and begins to seriously engage in physics and chemistry. In 1891, Rutherford made his first report on the theme "Evolution of the elements." In it, for the first time in history, the idea was expressed that atoms are complex structures.

Then scientific circles were dominated by Dalton's idea that atoms are indivisible. To all those who surrounded Rutherford, his idea seemed to be perfect madness. The young scientist had to constantly apologize to colleagues for his "nonsense". But 12 years later, Rutherford still managed to prove his case. Rutherford had a chance to continue his studies at the Cavendish Laboratory in England, where he began to study the processes of ionization of air. The first discovery of Rutherford was alpha and beta rays.

Rutherford's experience

Briefly about the discovery can be described as follows: in 1912, Rutherford, along with his assistants, conducted his famous experiment - the alpha particles were emitted from a lead source. All the particles, except those that were absorbed by lead, moved along the established channel. Their narrow stream fell on a thin layer of foil. This line was perpendicular to the sheet. Rutherford's experience in scattering alpha particles proved that the particles that passed through the foil sheet through and through, called so-called scintillations on the screen.

This screen was covered with a special substance, which began to glow when an alpha particle struck it. The space between the gold foil layer and the screen was filled with vacuum so that the alpha particles do not dissipate in the air. Such a device allowed researchers to observe particles that are scattered at an angle of about 150 °.

If the foil was not used as an obstacle to a beam of alpha particles, a light circle of scintillations was formed on the screen. But as soon as a barrier of gold foil was placed in front of their beam, the picture changed greatly. Flashes appeared not only outside this mug, but also on the opposite side of the foil. Rutherford's experience in the scattering of alpha particles showed that most of the particles pass through the foil without noticeable changes in the trajectory of motion.

At the same time, some particles deviated at a rather large angle and even were thrown back. For every 10,000 freely passing through the layer of gold foil particles, only one was deflected by an angle exceeding 10 ° - as an exception, one of the particles was deflected by such an angle.

The reason for the deflection of alpha particles

What Rutherford's experience has examined in detail and proved is the structure of the atom. This situation indicated that the atom does not represent a continuous education. Most of the particles pass freely through a foil one atom thick. And since the mass of the alpha particle is almost 8,000 times larger than the mass of the electron, the latter could not significantly affect the trajectory of the alpha particle. This could be done only by an atomic nucleus - a body of small dimensions, possessing almost the entire mass and the entire electric charge of the atom. At that time, it became a significant breakthrough of the English physicist. The experience of Rutherford is considered one of the most important steps in the development of the science of the internal structure of the atom.

Other discoveries obtained in the process of studying the atom

These studies have become direct evidence that the positive charge of an atom is inside its nucleus. This area occupies a very small space in comparison with its integral dimensions. In such a small volume, the scattering of alpha particles turned out to be very unlikely. And those particles that passed near the region of the atomic nucleus experienced sharp deviations from the trajectory, because the repulsive forces between the alpha particle and the nucleus of the atom were very powerful. Rutherford's experience in scattering alpha particles has proved the probability that an alpha particle will fall directly into the nucleus. True, the probability was very small, but still not equal to zero.

This was not the only fact that proved the experience of Rutherford. The structure of the atom was briefly studied by his colleagues, who made a number of other important discoveries. In addition to the teaching that alpha particles are rapidly moving helium nuclei.

The scientist was able to describe the structure of the atom, in which the nucleus occupies an insignificant part of the entire volume. His experiments proved that practically the entire charge of an atom is concentrated within its nucleus. In this case, both cases of deflection of alpha particles occur, as well as cases of their collision with the nucleus.

Rutherford's experiments: the nuclear model of an atom

In 1911, after numerous studies, Rutherford proposed a model of the structure of the atom, which he called planetary. According to this model, inside the atom there is a nucleus, which contains practically the entire mass of the particle. Electrons move around the nucleus just as the planets around the Sun do. From their totality, a so-called electronic cloud is formed. The atom has a neutral charge, as shown by the experience of Rutherford.

The structure of the atom was further interested in the scientist named Niels Bohr. It was he who finalized the teachings of Rutherford, because before Bohr the planetary model of the atom began to face difficulties of explanation. Since the electron moves around the nucleus along a certain orbit with acceleration, sooner or later it must fall on the nucleus of the atom. However, Niels Bohr was able to prove that the laws of classical mechanics do not work within the atom.