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A low-cost chaos dynamics lab is developed for quantitative demonstration of the butterfly effect using a magnetic pendulum. Chaotic motion is explored by recording magnetic time series. Students analyze the data in Excel® to investigate the butterfly effect as well as the reconstruction of the strange attractor using time delay plots. The lab exercise is suitable for junior-level modern physics laboratories, or as an extension to traditional first-year laboratories exploring pendulum motion.

Rocket experiments demonstrating conservation of momentum will never fail to generate enthusiasm in undergraduate physics laboratories. In this paper, we describe tests on rockets from two vendors that combine baking soda and vinegar for propulsion. The experiment compared two analytical approximations for the maximum rocket height to the experimentally measured rocket height. Baking soda and vinegar rockets present fewer safety concerns and require a smaller launch area than rapid combustion chemical rockets. Both kits were of nearly identical design, costing approximately $20. The rockets required roughly 30 minutes of assembly time consisting of mostly taping the soft plastic fuselage to the Styrofoam nose cone.

Numerical modeling studies have been carried out for the design of superconducting and high-permeability shields for SQUID-based nondestructive evaluation and biomagnetic measurements. We used finite-element-method software to model magnetic shields with both axial and planar symmetry in axial and transverse uniform noise fields. Improvements in signal-to-noise ratio at the location of the SQUID were calculated for different shield geometries with line current and magnetic dipole sources at various locations near the shield. Index Terms--Biomagnetism, finite-element method, magnetic shielding, nondestructive evaluation, SQUIDs.

Research describing the development of a superconducting quantum interference device based eddy current probe for nondestructive testing is presented. The probe utilizes a hybrid double-d sheet inducer coil.

Localized high temperature superconducting quantum interference devices were used for reducing ambient magnetic fields. Results were quantified in terms of signal-to-noise ration for source fields and shielding factors for ambient noise. The approach has potential applications in the magnetocardiography and nondestructive testing of materials in a nondestructive environment.

An electromagnetic flaw model and imaging techniques are developed simulating the magnetic nondestructive evaluation of proton exchange membrane fuel cells. A small flaw model is introduced to simulate the perturbation in magnetic field due to pinholes in the membrane. An inversion scheme is demonstrated to reconstruct the ionic current distribution in the membrane. Methods of stray field removal are then discussed. The research objectives of the above techniques are to locate flaws and enable the determination of current density in the fuel cell membrane in the presence of stray fields produced by electrodes, current leads, and background noise sources. [ABSTRACT FROM AUTHOR]

We report the nonlinear response of tissue and nerve fibers in the earthworm Lumbricus terrestris to sinusoidal electric field excitations. A High-Tc Superconducting Quantum Interference Device (SQUID) magnetometer detects the magnetic field generated by complex currents in the animal. SQUID signals are processed on a Fast Fourier Transform (FFT) spectrum analyser. Use of the SQUID eliminates low frequency polarization impedance and field distortion that would be present near pickup electrodes. Electrical 4-probe harmonic response measurements of the excised nerve fiber are then compared to the driven Hodgkin-Huxley active transport model. [ABSTRACT FROM AUTHOR]