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The electrical circuit of the jumping ring experiment based on discharging a capacitor is optimized. The setup is scoop proof at 46?V and yet the ring jumps more than 9?m high. The setup is suitable for both lectures and student laboratory work in higher education.

A high standard of living causes a large number of irreversible processes, which generate entropy. Energy flow is necessary to remove entropy from the location of generation; commonly this is called energy consumption. The usefulness of an energy flow is defined by its capability of removing entropy from an irreversible process. Fossil energy sources are limited and their use causes ecological damage and conflicts about distribution. As a long-term alternative, energy needs to be obtained from the incoming stream of solar radiation, or indirectly by replacing natural heat engines with artificial ones. Due to the environmental side effects of this replacement, unnecessary artificial entropy production has to be minimized.

An ultra-capacitor in parallel with the output of a dc power supply reduces the source resistance and yields an electrical current of up to 900A through a low resistance load. The magnetic field of wires is made visible with iron filings over a large area.

We present an experiment for education which demonstrates random transmission or reflection of heralded single photons on beam splitters. With our set-up, we can realize different quantum random experiments by appropriate settings of polarization rotators. The concept of entanglement is motivated by correlated randomness. The experiments are suitable for undergraduate education and are available as interactive screen experiments.

Single photons are used for fundamental quantum physics experiments as well as for applications. Originally being a topic of advance courses, such experiments are increasingly a subject of undergraduate courses. We provide interactive screen experiments (ISE) for supporting the work in a real laboratory, and for students who do not have access to a quantum optics laboratory. The main focus of the ISE is on undergraduate education, but some of the experiments are suitable for other levels of higher education as well.

The simultaneous sound of several voices or instruments requires proper tuning to achieve consonance for certain intervals and chords. Most instruments allow enough frequency variation to enable pure tuning while being played. Keyboard instruments such as organ and piano have given frequencies for individual notes and the tuning must be based on a compromise. The equal temperament is not the only solution, but a special choice. Unequal temperaments produce better results in many cases, because important major thirds and triads are improved. Equal temperament was not propagated by Johann Sebastian Bach, as is often stated in introductory literature on this topic.

The Barkhausen effect can be impaired by various noise sources. These are avoided by a hum-bucking coil, earthing, a preamplifier with carefully chosen bandwidth, and matching the input resistor to the inductance of the coil. The present setup is suitable for lecture hall demonstration in higher education institutes.

Acceleration of a common car with with a turbocharged diesel engine is compared to the same type with an electric motor in terms of kinematics. Starting from a state of rest, the electric car reaches a distant spot earlier than the diesel car, even though the latter has a better specification for engine power and average acceleration from 0 to 100 km h−1. A three phase model of acceleration as a function of time fits the data of the electric car accurately. The first phase is a quadratic growth of acceleration in time. It is shown that the tenfold higher coefficient for the first phase accounts for most of the kinematic advantage of the electric car.

A rotor of 12 cm diameter is attached to a precision electric motor, used as a generator, to make a model wind turbine. Output power of the generator is measured in a wind tunnel with up to 15 m s−1 air velocity. The maximum power is 3.4 W, the power conversion factor from kinetic to electric energy is cp = 0.15. The v3 power law is confirmed. The model illustrates several technically important features of industrial wind turbines quantitatively.