Oscillations and Mechanical Waves, Acoustics

Principle Cork dust in a glass tube is set into tiniest motion by a sound wave. If the frequency of the sound wave matches the natural frequency of the volume in the glass tube, a standing wave will form. The cork dust then assembles in visible patterns that show the nodes of pressure and motion […]

Principle A tensioned metal string is made to vibrate. The vibrations of the string are optically scanned, the vibration process observed on the oscilloscope and the dependence of the frequency on the string tension and string length and the density of the material are investigated. Benefits Investigation of the dependency of the vibration frequencies of […]

Principle A quadrangular rubber rope is inserted through the demonstration motor and a linear polarised fixed wave is generated. With the help of a stroboscope, the frequency and the wave length are determined. Then the phase velocity of ropewaves with a fixed tensile stress is ascertained. Subsequently, the mathematical relationship between the phase velocity of […]

Principle The velocity of sound in acrylics shall be determined by time of flight reflection technique with an ultrasonic echoscope. The measurements are done by reflection method, on three cylinders of different length. Two measurement series are carried out with ultrasonic probes of different frequencies. Benefits Introductory experiment for echoscopy applications Experiment can be easily […]

Principle The fundamental principles concerning the generation of ultrasonic B-scan images (brightness representation of the reflection amplitudes) are demonstrated with the aid of a simple test ob-ject. The experiment is executed with an ultrasonic echoscope in the pulse-echo-mode and the object is scanned manually. Then, the image quality and the most important image defects will […]

Principle An ultrasonic wave transmitted in a sample will be reflected at discontinuities (defects, cracks). From the relationship between the time of flight of the reflected wave and the sound velocity, the distance between ultrasonic transducer and defects (reflector) can be calculated. Position and size of these defects can be determined by measuring in different […]

Principle Acoustic cavity resonators possess a characteristic frequency which is determined by their geometrical form. In this case the resonator is excited to vibrations in its resonance frequency by background noise. Benefits Measure the resonance frequencies without additional excitation by using only the ambient noise Immediate observation of both, the sound wave signal and the […]

Principle If an emitter of sound or a detector is set into motion relative to the medium of propagation, the frequency of the waves that are emitted or detected is shifted due to the Doppler effect. Benefits Easy frequency setting thanks to digital function generator Intuitive measuring instrument Results well reproducible because of the motor-driven […]

Principle The velocity of sound in air is determined by measurement of sound travel times across known distances. Benefits Perfect as demonstration and student experiment Easy setup and fast procedure Easy entry into the topic of error calculation possible Tasks Determine the sound velocity in air for different distances between sound source and microphone. What […]

PrincipleThe velocity of sound in air is determined by measurements of sound travel times. Benefits Simple set-up and procedure Easy entry into the topic of error calculation possible Simplified implementation: all pre-settings already prepared Tasks Determine the speed of sound in air. What you can learn about Propagation of sound waves Velocity of sound Sound […]

Principle A set of circular water waves is generated simultaneously and the resulting interference is observed. By increasing the number of interfering circular waves, Huygens’ Principle can be verified. With the aid of plane water waves, diffraction phenomena of waves at different obstacles (slit, edge, double-slit etc.) are investigated. In a further experiment, the principle of […]

PrincipleThe periodicity of connected stationary oscillators is demonstrated on the example of a continuous, harmonic transverse wave generated by a wave machine. The number of oscillations carried out by different oscillators within a certain time is determined and the velocity of propagation is measured. A relation between frequency, wavelength and phase velocity is established. The […]

PrincipleSquare and round metal plates are brought to vibrate through acoustic stimulations by a loudspeaker. When the driving frequency corresponds to a given Eigen-frequency (natural vibration mode) of the plate, the nodal lines are made visible with sand. The sand is expelled from the vibrating regions of the plate and gathers in the lines because […]

Principle Bars of various materials will be exciting into torsional vibration. The relationship between the vibration period and the geometrical dimensions of the bars will be derived and the specific shear modulus for the material determined. Benefits The use of eight different rods out of different material and with several diameters increase the understanding of […]

Principle If an oscillating system is allowed to oscillate freely, we can observe that the decrement of successive maximum amplitudes strongly depends on the damping value. If the oscillating system is caused to oscillate by an external torsional oscillation, we can observe that the amplitude in a stationary state is a function of the frequency […]

Principle If an oscillating system is allowed to swing freely it is observed that the decrease of successive maximum amplitudes is highly dependent on the damping. If the oscillating system is stimulated to swing by an external periodic torque, we observe that in the steady state the amplitude is a function of the frequency and […]

Principle The spring constant D is determined for different experimental set-ups from the oscillation period and the suspended mass. Tasks Determination of the spring constant D for different springs. Determination of the spring constant for springs linked in parallel. Determination of the spring constant for springs linked in series. Benefits Large and sturdy set-up suitable for demonstration and lab […]

Principle Two identical gravity pendula with a particular characteristic frequency are coupled via a “soft” spiral spring. The amplitudes of both pendula are recorded as a function of time. The coupling factors are determined by way of different methods. Then, the local points of the oscillation are integrated into the video. Benefits Large and sturdy […]

Principle Two equal gravity pendula with a particular characteristic frequency are coupled by a “soft” spiral spring. The amplitudes of both pendula are recorded as a function of time for various vibrational modes and different coupling factors. The coupling factors are determined by different methods. Benefits Large and sturdy set-up suitable for demonstration and lab […]

Principle Investigate the oscillation behaviour of a pendulum (rod pendulum) by varying the magnitude of the components of the acceleration of gravity which are decisive for the oscillation period. The pendulum that is to be used is constructed in such a manner that its oscillation plane can be progressively rotated from a vertical orientation to […]

Principle By means of a reversible pendulum, terrestrial gravitational acceleration g may be determined from the period of oscillation of a physical pendulum, knowing neither the mass nor the moment of inertia of the latter. Benefits Quick and easy set-up Determine the gravitational constant g immediately without knowledge of mass or moment of inertia Automatically […]

Principle A mass, considered as of point form, suspended on a thread and subjected to the force of gravity, is deflected from its position of rest. The period of the oscillation thus produced is measured as a function of the thread length and the angle of deflection. Benefits Quick and easy set-up Automatically measure the […]