Eugen Goldstein: Discoveries and Contributions

Eugen Goldstein He was a leading German physicist, born in modern Poland in 1850. His scientific work includes experiments with electrical phenomena in gases and cathode rays.

Goldstein identified the existence of protons as equal and opposite charges to electrons. This discovery was carried out through experimentation with cathode ray tubes, in 1886.

Beams of electrons are directed from the cathode to the anode.

One of his most outstanding legacies consisted in the discovery of what is now known as protons, along with channel rays, also known as anodic or positive rays.

Was there an atomic model of Goldstein?

Goldstein did not propose an atomic model, although his discoveries allowed the development of the atomic model of Thomson .

On the other hand, he is sometimes credited as the discoverer of the proton, which I observe in the vacuum tubes where he observed the cathode rays. Nevertheless, Ernest Rutherford is considered the discoverer in the scientific community.

Experiments with cathode rays

Crookes tubes

Goldstein began his experiments with Crookes tubes during the decade of the 70s. He then made modifications to the structure developed by William Crookes in the 19th century.

The base structure of the Crookes tube consists of an empty tube made of glass, inside which gases circulate. The pressure of the gases inside the tube is regulated by moderating the evacuation of the air inside it.

The apparatus has two metal parts, one at each end, which act as electrodes, and both ends are connected to external voltage sources.

When electrifying the tube, the air ionizes and becomes a conductor of electricity. Consequently, the gases become fluorescent when the circuit between the two ends of the tube is closed.

Crookes concluded that this phenomenon was due to the existence of cathode rays, that is, flow of electrons. With this experiment the existence of elementary particles with negative charge in the atoms was demonstrated.

Modification of Crookes tubes

Goldstein modified the structure of the Crookes tube, and added several perforations to one of the tube's metal cathodes.

In addition, he repeated the experiment with the modification of the Crookes tube, increasing the tension between the ends of the tube to several thousand volts.

Under this new configuration, Goldstein discovered that the tube emitted a new glow that started from the end of the tube that had been perforated.

However, the highlight is that these rays moved in the opposite direction to the cathode rays and were called channel rays.

Goldstein concluded that, in addition to the cathode rays, which traveled from the cathode (negative charge) to the anode (positive charge), there was another ray traveling in the opposite direction, that is, from the anode to the cathode of the modified tube.

In addition, the behavior of the particles with respect to their electric field and magnetic field, was totally opposite to that of the cathode rays.

This new flow was baptized by Goldstein as channel rays. Because the channel rays traveled in the opposite direction to the cathode rays, Goldstein inferred that the nature of their electrical charge must also be the opposite. That is, the channel rays had a positive charge.

The channel rays

Channel rays arise when the cathode rays collide with the atoms of the gas that is confined inside the test tube.

The particles with equal charges repel. Starting from this base, the electrons of the cathodic ray repel the electrons of the atoms of the gas, and these last ones are detached from their original formation.

Gas atoms lose their negative charge, and are positively charged. These cations are attracted to the negative electrode of the tube, given the natural attraction between opposing electric charges.

Goldstein called these rays"Kanalstrahlen", to refer to the counterpart of cathode rays. The positively charged ions that make up the channel rays move towards the perforated cathode until they pass through it, given the nature of the experiment.

Hence, that this type of phenomenon is known in the scientific world as channel rays, since they pass through the existing perforation in the cathode of the study tube.

Modification of the cathode tubes

Likewise, the essays of Eugen Godlstein also contributed in a remarkable way to deepening the technical notions about cathode rays.

Through experiments on evacuated tubes, Goldstein detected that cathode rays could project acute shadows of emission perpendicular to the area covered by the cathode.

This discovery was very useful to modify the design of the cathode tubes used to date, and place concave cathodes in their corners, to produce focused rays that would be used in a variety of applications in the future.

On the other hand, the channel rays, also known as anodic rays or positive rays, depend directly on the physicochemical characteristics of the gas contained within the tube.

Consequently, the relationship between the electrical charge and the mass of the particles will be different depending on the nature of the gas that is being used during the experiment.

With this conclusion, the fact that the particles came out of the gas, and not the anode of the electrified tube, was clarified.

Goldstein's Contributions

First steps in the discovery of the proton

Based on the certainty that the electrical charge of the atoms is neutral, Goldstein took the first steps to verify the existence of fundamentally charged particles.

Foundations of modern physics

Goldstein's research brought with him the foundations of modern physics, since the demonstration of the existence of channel rays allowed to formalize the idea that atoms moved quickly and with a specific movement pattern.

This type of notions was key in what is now known as atomic physics, that is, the field of physics that studies the behavior and the properties of the atoms in all their extension.

Isotope study

Thus, Goldstein's analysis led to the study of isotopes, for example, among many other scientific applications that are currently in full force.

However, the scientific community attributes the discovery of the proton to the New Zealand chemist and physicist Ernest Rutherford , in the middle of 1918.

The discovery of the proton, as counterpart of the electron, laid the foundations for the construction of the atomic model that we know today.

References

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