The operation of the puzzling "forever spin" top is explained. This toy makes an intriguing basis for discussion of the physical principles involved. (Contains 8 figures and 1 footnote.)

To demonstrate the different vibration characteristics of a magnetic spring compared with those of a metal one, a magnetic spring apparatus was constructed from a pair of circular magnets of the same size with an inside diameter of 2.07 cm and an outside diameter of 4.50 cm. To keep the upper magnet in a suspension state, the two magnets were…

Anisotropy is a difficult concept, although it is often met in everyday life. This paper describes a simple model--knitted patterns--having anisotropic elastic properties. The elastic constant is measured for the force applied in different directions with respect to the knitting direction. It is also shown that the deformation of the knitted…

Energetic materials (EMs) are substances with a high amount of stored energy and the ability to release that energy at a rapid rate. Nanothermites and green organic energetics are two classes of EMs which have gained significant interest as they each have desirable properties over traditional explosives. These systems also possess downfalls, which…

Recently, developments in novel and high-purity materials allow for the presence of a single, solitary crystalline defect to define the electronic, magnetic, and optical functionality of a device. The discrete nature of the active dopant, whose properties are defined by a quantum mechanical description of its structure, enables radically new…

The focus of a parabola rolling without sliding along a straight line traces a catenary. We give some historical notes on this classical kinematical construction, observe that it was rediscovered in a recent article, and give a simpler and more geometric alternative derivation.

Using a data-acquisition system, the charge and energy stored in a capacitor are measured and displayed during the charging/discharging process. The experiment is usable as a laboratory work and/or a lecture demonstration. (Contains 3 figures.)

Presented here is an adaptation of George Gamow's derivation of the centripetal acceleration formula as it applies to Earth's orbiting Moon. The derivation appears in Gamows short but engaging book "Gravity", first published in 1962, and is essentially a distillation of Newton's work. While "TPT" contributors have offered several insightful…

Evaporation of a small glass of ethylic alcohol is studied both experimentally and through an elementary thermal physics approach. For a cylindrical beaker and no air flow in the room, a simple quadratic relation is found between the evaporation time and the mass of evaporated liquid. This problem and the obtained results offer excellent…

Hardly. Just as Robert Johns qualitatively describes angular acceleration by an internal force in his article "Acceleration Without Force?" here we will extend the discussion to consider angular acceleration by an internal torque. As we will see, this internal torque is due to an internal force acting at a distance from an instantaneous center.

We present a showcase with interactive exhibits of basic physical experiments that constitutes a complementary method for teaching physics and interesting students in physical phenomena. Our interactive physics showcase, shown in Fig. 1, stimulates interest for science by letting the students experience, firsthand, surprising phenomena and…

The ancient Babylonians had an iterative technique for numerically approximating the values of square roots. Their method can be physically implemented using series and parallel resistor networks. A recursive formula for the equivalent resistance R[subscript eq] is developed and converted into a nonrecursive solution for circuits using…

When wave vortices, that is nodal lines of a complex scalar wavefunction in space, approach transversely, their typical crossing and reconnection is a two-stage process incorporating two well-understood elementary events in which locally coplanar hyperbolas switch branches. The explicit description of this reconnection is a pedagogically useful…

The purpose of this study was to investigate the effects of learning activities based on argumentation about "Force and Motion" unit on conceptual understanding and views about establishing thinking friendly classroom environment of 7th graders. The study was conducted with total 39 students (20 students in experimental group and 19…

We compare student learning and perception data from astronomy, physics, and geology courses taught in a traditional classroom with individual desks to the same classes taught in a large auditorium. In a large student sample (1,593 students), there is no clear difference between rooms in measures of failure rates or average final grades. However,…