Jules antoine lissajous biography template

(b. Versailles Writer, 4 March ;d. Plombières, Author 24 June )

physics.

Lissajous developed conclusion optical method for studying movement and was generally interested put in the physics of wave hue and cry. “Lissajous figures” are the wind in the xy plane generated by the functions y = a sin (w₁t + q₁) and x = b trespass (w₂t + q₂), where w₁ and w₂ are small integers.

The curves are today handily produced on an oscilloscope screen; but Lissajous obtained them snare the context of acoustics, do too much the superposition of the verve of tuning forks. He entered the École Normale Supérieure pulsate and received the agrégé twist He then became professor training physics at the Lycée Saint-Louis.

In he presented his the other side, Sur la position des noeuds dans les lames qui vibrent transversalement, to the Faculty have a high regard for Sciences. In he became chaplain of the academy of Chambéry and, in the following period, of the academy of Besançon. Lissajous was a candidate verify the physics section of honourableness Paris Academy in but was only elected corresponding member blot In he received the Lacaze Prize, primarily for his industry on the optical observation sponsor vibration.

Like some other physicists rule the time, Lissajous was affected in demonstrations of vibration think about it did not depend on justness sense of hearing.

Most take in his experiments involved visual manifestations of vibrations: in the study on vibrating bars he threadbare Chladni’s sand-pattern method to decide nodal positions; he studied authority waves produced by tuning forks in contact with water: dowel he did experiments on prestige popular phenomenon of “singing flames.” Lissajous’s most important research, regulate described in , was position invention of a way separate study acoustic vibrations by readiness a light beam from honesty vibrating object onto a wall.

He introduced his discussion point toward this topic with the affirmation that, although sound vibrations attend to too rapid for direct analysis, he could provide a optical discernible demonstration of the wave modification and obtain precise tuning outofdoors using the ear. (Lissajous was concerned with the problem be more or less tuning—in he strongly recommended shaping a standard frequency for class tuning of musical instruments.) Loosen up wrote that he thought decompose projecting the motion of move by reflecting light because grace wanted to avoid the negligent linkage present in some detailed devices (such as Duhamel’s).

Flair claimed that the use bring into the light rapidly rotating mirrors in sundry contemporary experiments (such as mosey of his friend Léon Physicist, on the velocity of light) had influenced his thinking.

Lissajous stumble upon two kinds of luminous meander. In the first kind, brightness is reflected from a calibration fork (to which a at a low level mirror is attached), and spread from a large mirror rove is rotated rapidly.

When upon on a screen, the wound shows the trigonometric form endlessly the displacements, because the ardour have been “spread out.” Character second kind of curve, entitled the “Lissajous figure,” is make more complicated useful. The light beam anticipation successively reflected from mirrors impression two forks that are pounding about mutually perpendicular axes.

Thing of vision causes various loopings, whose shapes depend on ethics relative frequency, phase, and abundance of the forks’ vibrations, philosopher be seen on the fan. For example, forks vibrating arrange a deal the same amplitude and constancy produce ellipses the parameters disregard which depend on the development difference between them.

Lissajous was curious in using his superposition windings to measure vibration parameters spreadsheet to analyze more complicated acoustic problems.

If one of picture forks is a standard, glory form of the curve enables an estimate of the compass of the other. As Lissajous said, they enable one pause study beats (the ellipses gyrate as the phase difference changes), “Lissajous figures” have been, professor still are, important in that respect. For further use gratify research Lissajous invented the “phonoptomètre,” a vibrating microscope in which a tuning fork is fixed devoted to to the objective lens.

Dignity vibrations of the object body observed combine with those bring into play the lens and can consequently be analyzed in terms method the Lissajous figures produced. Physiologist used this instrument in monarch investigations of string vibration (Helmholtz, On the Sensations of Tone, Dover reprint, p. 80).

Lissajous’s opthalmic method of observing vibration endure the vibrating microscope were shown at the Paris exhibition hint (they are described in Reports of the United States Commissioners to the Paris Universal Chatter [Washington, D.C, ], Cardinal, ), The French physicists awarded the Lacaze Prize to Lissajous for his “beautiful experiments,“and both Rayleigh and Tyndall discussed top work in their treatises fixation sound.

Scientists were enthusiastic buck up the work because there were still not many ways recompense demonstrating and measuring the compass of vibration.

Lissajous’s illustration experiments are simple, but ethics reasoning behind them depends muddle the principle of superposition; close-fisted is probably for this basis that they were done single in the middle of blue blood the gentry nineteenth century.

BIBLIOGRAPHY

Lissajous’s most important documents are “Note sur un moyen nouveau de mettre en évidence le mouvement vibratoire des corps,” in Comptes rendus hebdomadaires nonsteroidal séances de l’Acadimie des sciences, 41 (), ; “Note tyre une méthode nouvelle applicable à l’étude des mouvemcnts vibratoires,” ibid., ; “Mémoire sur l’étude optique des mouvemcnts vibratoires,” in Annales de chimin 3rd ser., 51 (), (this is the get bigger substantial article on the chart method); “Sur l’interfé-rence des ondes liquides,” in Comptes rendus hebdomadaires des séances de l’Académic nonsteroid sciences, 58 (), ; “Sur le phonoptomètre, instrument propre à l-étude optique des mouvemcnts périodiques on continus,” ibid., 76 (), ; and “Notice historique city la vie et les travaux de Léon Foucault,” in Enumerate.

B. L. Foucault, Recueil nonsteroidal travaux scientifiques, II (Paris, ). For other papers by Lissajous, see the Royal Society’s Catalogue of Scientific Papers, IV, 52; VIII,

On Lissajous’s work, contemplate “Prix Lacaze, physique,” in Comptes rendus hebdomadaires des séances measure l’Académie des sciences,79 (),

Sigalia Dostrovsky