In this paper we present a system aimed at demonstrating the photoacoustic (PA) effect for educational purposes. PA imaging is a hybrid imaging modality that requires no contrast agent and has a great potential for spine and brain lesion characterisation, breast cancer and blood flow monitoring notably in the context of fetal surgery. It relies on…

By superimposing two sound waves of the same wavelength, propagating in the opposite direction, we can create an intensity pattern having a characteristic scale equal to half a wavelength: it is the diffraction limit. Recently a group from the Institut Laue-Langevin in Paris has shown that it is possible to go beyond this limit by focusing sound…

In this paper we investigate the speed of sound in air as a function of temperature using a simple and inexpensive apparatus. For this experiment it is essential that the appropriate end corrections be taken into account. In a recent paper the end corrections for 2-in i.d. (5.04-cm) PVC pipes open at both ends were investigated. The air column…

A Smartphone is not only a mobile device that is used for communication but is also integrated with a personal digital assistant (PDA) and other technological capabilities such as built-in acceleration, magnetic and light sensors, microphone, camera and Global Positioning System (GPS) unit. This handheld device has become very popular with the…

Sound tubes, pipes, and singing rods are used as musical instruments and as toys to perform amusing experiments. In particular, corrugated tubes present unique characteristics with respect to the sounds they can produce; that is why they have been studied so intensively, both at theoretical and experimental levels. Experimental studies usually…

This paper describes theory and experiments, taken from biophysics and physiological measurements, to illustrate the technique of signal averaging. In the process, students are introduced to the basic concepts of signal processing, such as digital filtering, Fourier transformation, baseline correction, pink and Gaussian noise, and the cross- and…

An experimental system for detecting infrared absorption using the photoacoustic (PA) effect is described. It is aimed for use at high-school level to illustrate the difference in infrared (IR) absorption among the gases contained in the atmosphere in connection with the greenhouse effect. The experimental system can be built with readily…

In this article, the authors describe steps on how to develop a high-impact activity in which students build, test, and improve their own "coffee can" speakers to observe firsthand how loudspeakers work to convert electrical energy to sound. The activity is appropriate for students in grades three to six and lends itself best to students…

Describes some undergraduate laboratory experiments in acoustics which involve the analysis of speech and musical instrument sounds and the general analysis of the frequency range of complex sounds. (HM)

Provides the background theory and some experiments for studying static equilibrium using a Slinky. (MVL)

An experiment in which both Raman-Nath and Bragg diffraction of light by acoustic waves in water are observed in the sound frequency range from 5 to 45 MHz. The apparatus consists of a laser, light detector, rf power source, quartz transducer, and homemade water cell. (Author/DF)

Describes some experiments of parametric effects intended to be disigned by the students themselves and shows how to introduce parametric interactions and nonlinearities to the students in a simple manner. (GA)

A qualitative demonstration of wave motion along a linear spring is being used, quantitavely, to present three methods of measuring the phase velocity of the waves. (GA)

Discusses the use of 40 kHz ultrasonic transducers to study wave phenomena. Determines that the resulting wavelength of 9 mm allows acoustic experiments to be performed on a tabletop. Includes transducer characteristics and activities on speed of sound, reflection, double- and single-slit diffraction, standing waves, acoustical zone plate, and…

Presents hands-on science activities that help students learn the concepts of hearing and sound while allowing students to practice science process skills. Students investigate the use of alternative phonograph speakers and needles and apply the knowledge learned to the construction of one-string banjos. (MDH)