Rev. Inv. Fis. 19, 161901551 (2016) 1 Use of the Logarithmic Decrement to Assess the Damping in Oscillations Javier Montenegro Joo Facultad de Ciencias Físicas – Universidad Nacional Mayor de San Marcos (UNMSM, Lima Perú) VirtualDynamics: Science & Engineering Virtual Labs. Director@VirtualDynamics.Org Abstract A Virtual Lab to experimentally detect the frequency of the oscillations of a damped oscillator has been created. Once input data (mass, elastic constant and damping of the medium) are entered, the simulation module depicts the oscillations on computer screen, automatically detects the extreme displacements of oscillation and applies the logarithmic decrement algorithm, which leads to the exponent characterizing the gradual shrinking of displacements. From this exponent the frequency of the damped oscillations is calculated, this –as it is expected- is equal to its theoretically calculated value. Keywords: Damped oscillations, logarithmic decrement, computer simulation, Virtual Lab. Resumen Se ha creado un Laboratorio Virtual para detectar experimentalmente la frecuencia de oscilación de un oscilador amortiguado. Una vez que se introducen los datos de entrada (masa, constante elástica y amortiguación del medio) el módulo muestra las oscilaciones en la pantalla de la computadora, detecta automáticamente los desplazamientos extremos de la oscilación y aplica el algoritmo de Decremento Logarítmico, que conduce al exponente que caracteriza la contracción gradual de los desplazamientos. De este exponente se calcula la frecuencia de las oscilaciones amortiguadas oscilador, este resultado – tal como se espera- es igual al valor calculado teóricamente. Palabras clave: Oscilaciones amortiguadas, decremento logarítmico, simulación en computadora, Laboratorio Virtual. Introduction In a damped oscillating system, where the damping is not known, the Logarithmic Decrement may be used to find the damping of the system [1,2]. The logarithmic decrement is defined as the natural logarithm of the ratio of any two successive maximum displacements in a damped oscillation. Obviously these two maximum amplitudes      are separated by a certain time t:            The exponent is negative because in a damped system the amplitudes of the oscillations shrink. In the case with no damping, if the amplitudes of the oscillations would increase, the exponent would be positive and, if the amplitudes were constant, the exponent would be zero. The expression above is valid provided the oscillations are uniform; this is, as long as the distance between orbits in State Space keeps constant. In Chaotic oscillators the displacements are far from being uniform and the State Space is literally chaotic, in the most common sense of the word [3].