Lipman (Lippmann), Gabriel

August 6, 1845, Mr.. - July 12, 1921
French physicist Gabriel Lippman Jonas was born in Hollerihe (Luxembourg). Until the age of thirteen, he studied at home, and parents after moving to Paris, entered the Lycц?e Napoleon. In 1868, Mr.. L. became a student at Ecole normal syuperer. Preparation German abstracts of articles for the French magazine 'Annals of Chemistry and Physics' ( "Annales de Chimie et de Physique") aroused his interest in the study of electricity.
. During a government-funded trips to Germany (1873) to study methods of teaching science L
. worked at the University of Heidelberg with a physiologist Wilhelm Kц?hne and physicist Gustav Kirchhoff, and then in Berlin with a physiologist and physicist Hermann von Helmholtz. Kuehne showed L. experience, in which a drop of mercury covered with sulfuric acid, deformed when touched lightly iron wire. L. concluded that the metals and sulfuric acid form the electric battery, the voltage which changes the shape of the surface of mercury. This happy conjecture allowed him to create a capillary electrometer (or voltmeter) - sloping capillary glass tube in which the surface of the mercury column is sulfuric acid. Electricity induced changes in the curved surface of mercury forced the mercury to move in the capillary, and these movements are able to measure the electrical potential difference of up to 0,001 volts.
. Upon his return to Paris to complete the formation of L
. conducted research electrocapillary, the influence of electric fields on the surface tension of liquids, and in 1875. defended at the Sorbonne a thesis for a doctorate. In 1878, Mr.. He became a member of the Faculty of Natural Sciences, University of Paris, and in 1883. was appointed professor of mathematical physics. In 1886. L. became the leader of the research laboratory, a staff member who stayed until the end of his life.
L. conducted a study the effect of education electricity under the influence of mechanical deformation of the mercury surface. It was a phenomenon opposite to where the action is based capillary electrometer. This work helped L. formulate a general theorem which he published in 1881. This theorem states that, knowing of the existence of a physical phenomenon, we can predict the existence and magnitude of the reverse effect. L. applied his theorem to the phenomenon of piezoelectricity - the emergence of electric charges in compression or stretching of certain crystals such as quartz. Since mechanical forces, giving rise to the charges, alter the size of the crystal (the change of the size leads to stress), L. predicted that if the crystal to make voltage, it will change its size. Pierre Curie and his brother Jacques confirmed the assumption N. experimentally.
Inverse piezoelectric effect is now widely used in science and technology. Applied to the piezoelectric crystals alternating voltage forcing them to vibrate and emit sound waves, . that finds application in sonar (devices for detecting submarines), . different ultrasonic devices, . used for cleaning surfaces, . remote control and in dental drills.,
. In 1879, Mr.
. L. suggested that the electric charge increases the inertia of the body - its resistance to change in the velocity. It is possible that at this point his observations prompted Michael Faraday (1838) and experiments GA. Rowland (1876), showing that a moving charge is equivalent to an electric current creates a magnetic field. But L. never referred to the experimental confirmation of his hypothesis, and is not engaged in its further development.
In 1891, Mr.. L. demonstrated a method for obtaining nevytsvetayuschih color photographs. The process, which yields color photos, was proposed in 1848. French physicist Edmond Becquerel. It used a silver plate, covered with a layer of silver chloride, but the picture quickly faded, and he Becquerel could not give an explanation of the formation of color images. After 20 years, the German physicist Wilhelm Zenker explained the emergence of color photographs Becquerel interference phenomenon. Zenker's theory was further developed in the works of English physicist J. U. Stratton and was confirmed experimentally in 1890. German physicist Otto Wiener.
Interference is not nothing but a combination of different light waves arriving simultaneously at the same point. Light is the electric and magnetic fields, the tensions which periodically increases, decreases and changes sign along the axes perpendicular to each other and the direction of propagation of light. Therefore, light waves can reinforce or weaken each other, depending on whether their intended field in the same direction or in opposite. If the light waves have the same length (and the corresponding frequency), then there is the interference pattern - a ring or band. Bright spots on it correspond to the arrival of the waves are in phase (at the same point of the full cycle of change), the dark - the arrival of waves in the opposite (in diametrically opposite points of the cycle). The distances between the spots on the interference pattern depends on the wavelength. Waves with different wavelengths, interfering, create images that are shifted relative to each other continuously, resulting in the overall picture is lubricated.
. On photographic plates Becquerel, . as explained Zenker, . incident light interferes with light waves of the same length, . reflected from the silver plate, . that generates a picture of the bright layers, . Situated across the half-wave intervals and separated by dark layers,
. Since the wavelength corresponds to the color, seen through the eyes, different colors create interference patterns at different depths and at different places on the plate, where they arise in the incident light. The light energy accumulated in each point of the film during exposure, determines the number of grains of metallic silver, which are formed from silver chloride with subsequent manifestation of the plate. These metal grains are copies of the interference patterns for different colors in the form of blackened layers located at different depths and with different lateral displacement.
When sharing a picture in normal light, ie. in a mixture of all colors, the light reflected from the layers of grains of metallic silver and silver plate from the most. Light waves, . reflected from layers of different depths, . exacerbated by the interference only when a well-defined wavelength (color), . appropriate distance between the layers, . and thus reproduce the color of the object photographed.,
. When L
. invented his method of color photography, allowing one to obtain images, does not fade soon after the manifestation, he denied that the color photographs by the method due to interference Becquerel. L. argued that the interference is the basis of his own method. L Plates. were made of clear glass and one side covered with relatively thick layer of photosensitive emulsion of gelatin, silver nitrate and potassium bromide. During the exposure cassette covers free side of the glass plate with mercury, . which created a brilliant reflective surfaces, . The interference pattern between light, . incident on the object and reflected from the mercury (it is these interference patterns are stored 'memory' of color images), . depicts the distribution of silver grains, . resulting from chemical reactions in the manifestation,
. Subsequently, L. vividly described invented a process as creating a kind of template or a form of light rays in the thicker films.
"For the creation of a photographic reproduction of colors on the basis of the interference phenomenon, 'L. was awarded the Nobel Prize in Physics 1908. Mentioning about the 'key position, which is a photographic reproduction of various objects in modern life', K.B. Hasselberg of the Royal Swedish Academy of Sciences at the award ceremony said that 'A method of color photography. marks a new step forward ... in the art of photography '. Speaking from the Nobel lecture, L. demonstrated, . that when his method of color really is caused by interference in the photographic plate without any dyes: he soaked emulsion, . gelatin swelled and the distance between the spots on the interference pattern changed, . color disappeared,
. But when gelatin dry up as interference patterns are recovered and regained its color image.
L. noted the need for further improvement of its methods: 'Duration of exposure (1 minute to the sun) is still too high for portrait photography. When I first started to work, duration of exposure reached 15 minutes. The process should be improved and further. Life is short, but progress is so slow '. Contemporary color photograph with films that require exposure to the fraction of a second, based on three-color process with absorbing dyes, first proposed in the 50-ies. XIX century. Scottish physicist James Clerk Maxwell.
In subsequent years, L. contributed greatly to the development of seismology and astronomy. He owns the idea of using telegraph signals for early warning of earthquakes and measuring the velocity of propagation of elastic waves in the crust. He proposed a new type of seismograph for direct measurement of acceleration in the movement of the earth's surface. L. developed a design of two astronomical instruments: tselostata with a slowly rotating mirror, . allows to obtain a stationary image portion of the sky, . which pointed tool, . not just a single star, . and uranography, . with which you can make a photographic map of the sky with the already deposited her meridians, . which is convenient to measure the equal time intervals,
. His textbook on thermodynamics (the science of the transformations of heat and its relation to mechanical energy) has become the standard course in France.
In 1888. L. married. He died on board the ship "La France", returning from a trip to Canada. L. was a member of the French Academy of Sciences (in 1912. - Its president), a member of the Royal Society of London. He was awarded the title Commander of the Order of the Legion of Honor.