Powerbanks differ in the amount of energy they can store. Usually this capacity (in a colloquial sense) of the powerbanks is stated in the form of charge in mAh for effective advertising. From a physical point of view, shouldn't the energy that a powerbank can provide be of interest? For students, charging smartphones with power banks is…

The smartphone's ambient light sensor has been used in the literature to study different physical phenomena. For instance, Malus's law, which involves the polarized light, has been verified by using simultaneously the orientation and light sensors of a smartphone. The illuminance of point light sources has been characterized also using the light…

Understanding Physics is a great end in itself, but is also crucial to keep pace with developments in modern technology. Wireless power transfer, known to many only as a means to charge electric toothbrushes, will soon be commonplace in charging phones, electric cars and implanted medical devices. This article outlines how to produce and use a…

Nuclear energy produces low carbon, safe and reliable electricity so is it now time for the UK to invest in this proven technology or are the misplaced perceptions regarding its safety, cost and the quantities of radioactive waste produced causing us to overlook nuclear as a major component of our electricity mix? This paper discusses these issues…

The classroom jumping ring demonstration is nearly always performed using alternating current (AC), in which the ring jumps or flies off the extended iron core when the switch is closed. The ring jumps higher when cooled with liquid nitrogen (LN2). We have performed experiments using DC to power the solenoid and find similarities and significant…

The 1990 film "The Hunt for Red October" (based on Tom Clancy's 1984 debut novel of the same name) featured actors like Sean Connery and Alec Baldwin, but the star of the movie for physicists was a revolutionary new magnetohydrodynamic (MHD) marine propulsion system. The so-called "caterpillar drive" worked with no moving…

Educating our future citizens in science and engineering is vitally important to ensure future advancement. Presently, in the light of environmental sustainability, it is critical that students learn concepts relating to energy, its consumption and future demands. In this article, we harness the state of the educational technology, namely…

When all parts of an electric circuit are at the same potential, no electric current flows and it is said to be in "equilibrium." Otherwise, a current will flow from the higher potential parts to the lower ones, as when we make contact between the plates of a charged capacitor. The resulting discharging process towards equilibrium is a…

A Genecon is an inexpensive hand-cranked dc electric generator. You can use it to charge a one-farad supercapacitor. If you stop cranking the handle, the capacitor will discharge, sending a current into the Genecon and thereby causing the handle to start turning as an electric motor. How does the current direction compare before and after you stop…

The construction of a voltaic pile (battery) is a simple laboratory activity that commemorates the invention of this important device and is of great help in teaching physics. The voltaic pile is often seen as a scientific toy, with the "pile" being constructed from fruit. These toys use some strips of copper and zinc inserted in a piece…

Typical commercial solar panels consist of approximately 60 individual photovoltaic cells connected in series. Since the usual Kirchhoff rules apply, the current is uniform throughout the circuit, while the electric potential of the individual devices is cumulative. Hence, a solar panel is a good analog of a simple resistive series circuit, except…

The bicycle generator is often mentioned as an example of a method to produce electric energy. It is cheap and easily accessible, so it is a natural example to use in teaching. There are different types, but I prefer the old side-wall dynamo. The most common explanation of its working principle seems to be something like the illustration in Fig.…

Harnessing energy from the tides is a much-promoted but rarely realised way of generating electricity. This article examines some of the systems that are currently in use or under development, and outlines their economic, environmental and technical implications.

The measurement of the force acting between two parallel, current-carrying wires is known as Ampère's experiment. A mechanical balance was historically employed to measure that force. We report a simple experiment based on an electronic precision balance that is useful in clearly showing students the existence of this interaction and how to…

We use a tablet to experimentally determine the dependencies of the magnetic field (B) on the electrical current and the axial distance from a coil (z). Our data shows good precision on the inverse cubic dependence of the magnetic field on the axial distance, B?z[superscript -3]. We obtain the value of air permeability µ[subscript air] with good…