Besides radiating sound from the note area being struck, a steelpan radiates from neighboring note areas that vibrate sympathetically, from the areas between notes, and from the skirt [Rossing et al., Phys. Today 49(3), 24-29 (1996)]. Measurements were taken in an anechoic chamber using a four-microphone intensity probe to visualize the acoustic radiation from selected notes on a double second and a low tenor steelpan. Swept sinusoidal excitation was effected using an electromagnet. Sound intensity maps were drawn for the first three harmonics.

The vibrational behavior of a tennis racket was studied using a speckle-pattern interferometry system. Specifically, the first 12 mode shapes of a racket are shown and discussed. In addition, the speckle-pattern interferometry system was used to compare the effects of four commercially available vibration damping systems. It was found that these vibration dampers produce a variety of effects on the vibrational behavior of the racket, though these effects may not be noticeable during play.

Methods for studying the modes of vibration and sound radiation from percussion instruments are reviewed. Recent studies on the acoustics of marimbas, cymbals, gongs, tamtams, lithophones, steelpans, and bells are described. Vibrational modes and sound radiation from the HANG, a new steel percussion instrument are presented.

Some effects of the asymmetries causing a splitting of the fundamental natural vibrating frequency of a wire have previously been reported [Hanson et al., J. Acoust Soc. Am. 103, 2873 (1998)]. It has been demonstrated in this work on brass harpsichord wire that the splitting of the frequency is due to intrinsic properties of the wire itself and not of asymmetries in the end clamps. The two frequencies are associated with two definite orientations with respect to the wire. These two vibrational directions have been determined to be orthogonal within one degree experimental uncertainty. This orthogonality is in agreement with predictions of a simple model which assumes that, for small-amplitude free vibrations, the observed portion of the wire moves under the action of a linear anisotropic conservative restoring force. Measured splittings for several samples of harpsichord wire have ranged from 0.12 to 0.30 Hz for a frequency of about 70 Hz. The nonlinear effects of generation of motion perpendicular to the driving direction [Hanson et al., J. Acoust. Soc. Am. 96, 1549–1556 (1994)] and generation of higher harmonics are profoundly influenced by the orientation of the driving direction with respect to these vibrational orientations for low-driving forces. Related effects for plucked strings will be discussed.

There is a wide variety of ways for instructors to seek to improve diversity, equity, inclusion, and respect (DEIR) in chemistry through their instruction. One way is to talk with students explicitly about equity and injustice in science. We propose a curricular framework for teaching about equity as a way to improve DEIR in science classes at the high school and college levels. The framework has six parts, including expansive framing, buy-in, active and collaborative learning, action, flexible content, and science as a context for learning. We also present the Underrepresentation Curriculum as an example of the framework for teaching about equity in science in action. The Underrepresentation Curriculum (underrep.com) is a flexible set of lesson plans that aims to help students learn about and take action to improve equity in science.