Jan-Peter Meyn

The phyphox app reads the acceleration sensor of a smartphone underwater while swimming. The app processes the raw data to determine the swimmer's speed over time. Certain body movements are identified in the speed function, such as an increase in speed caused by the arm pull. Depending on their prior knowledge, university students can reproduce the experiment with appropriate guidance or independently. However, the speed function cannot be calculated directly by integrating the acceleration data due to error caused by sensor noise. Additional measurements and assumptions must be made to obtain absolute speed values. Evaluating and critically using data promotes the development of skills in acquiring knowledge in physics. The results of the measurement can also help refine the swimmer's stroke and improve its efficiency. Thus, the presented method is not merely an exercise but a meaningful application of smartphone sensors.

Entropy and energy had not yet been introduced to physics by the time Carnot wrote his seminal Réflexions. Scholars continue to discuss what he really had in mind and what misconceptions he might have had. Actually, his work can be read as a correct introduction to the physics of heat engines when the term calorique is replaced by entropy and entropy is used as the other fundamental thermal quantity besides temperature. Carnot’s concepts of falling entropy as an analogy to the waterfall, and the separation of real thermal processes into reversible and irreversible processes are adopted. Some details of Carnot’s treatise are ignored, but the principal ideas are quoted and assumed without modification. With only two thermal quantities, temperature and entropy, modern heat engines can be explained in detail. Only after the principal function of heat engines is developed is energy introduced as physical quantity in order to compare thermal engines with mechanical and electrical engines and, specifically, to calculate efficiency.

No consensus has been reached so far concerning the key topics on quantum physics suitable for secondary school teaching, despite comprehensive research. We identified the the variety of associations with quantum physics among professionals as a potential cause. From an explorative mind map study with N = 29 physics researchers, we derive six subject-specific focal points in the associations that researchers have with quantum physics.

Physics teachers are often faced with the challenge of having to set up difficult experiments, or they have to consciously manipulate parameters in order to be able to demonstrate a phenomenon convincingly. Comprehensive laboratory courses are standard procedure in any study program for prospective physics teachers. However, many students, even after completing standard laboratory courses, show difficulties in standard experimental situations, such as measuring an electric current. We report on a new seminar concept for students in physics teacher study programs. This concept is based on the current state of research in physics education, on the teachers’ professional competences, and on the modelling of experimental competence, justifying its embedding in teacher training. We present first results of a pilot study carried out to evaluate the seminar.

In this article, an approach to integrate contemporary quantum physics into secondary school teaching is presented. The Erlanger concept on quantum optics provides an experimental-based guideway to aspects of modern quantum physics. We avoid the traditional historical approach in order to overcome the lack of modern concepts of quantum physics. In an acceptance survey, initial empirical evidence for the acceptance of the developed explanatory approaches was evaluated.

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 c _p = 0.15. The v ³ power law is confirmed. The model illustrates several technically important features of industrial wind turbines quantitatively.