In this article we present a simple experimental set-up to determine the band gap of germanium and silicon using the "ExpEYES-17" kit. The experiment is based on the temperature dependence of the reverse current through germanium and silicon diodes at different temperatures. The experimental values are found to agree well with accepted…

The video of a free-falling object was analysed in Tracker in order to extract the position and time data. On the basis of these data, the velocity, gravitational potential energy, kinetic energy, and the work done by gravity were obtained. These led to a rather simultaneous validation of the conservation law of energy and the work-energy theorem.…

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…

We present a simple activity based on the liquid-drop model which allows secondary school students to explore the uses of mathematical models and gain an intuitive understanding of the concept of binding energy, and in particular the significance of positive binding energy. Using spreadsheets provided as supplementary material, students can…

Drawing equipotential and electric field lines is an activity commonly found in most second-semester introductory physics courses. Unfortunately, current commercial lab offerings are expensive and do not afford the opportunity for real-time graphical visualization of the trends in voltage in different regions. In this brief article, we describe a…

This paper describes a number of active learning strategies based on implementing the Raspberry Pi as low-cost single-board computing device for carrying out physics laboratory activities. This Microcomputer-Based Laboratory (MBL) Project has been funded by the Baden-Württemberg Foundation and it encompasses the use of high-accuracy yet…

G, G°, [delta][subscript r]G, [delta][subscript r]G°, [delta]G, and [delta]G° are essential quantities to master the chemical equilibrium. Although the number of publications devoted to explaining these items is extremely high, it seems that they do not produce the desired effect because some articles and textbooks are still being written with…

A cordless mouse with an added reed switch is used as a wireless data logger to record every time the wheel of a trolley completes a revolution. The limitations of the system in terms of maximum clicking rate and spatial resolution are considered and data obtained from the descent of a trolley down a ramp at various different angles is analysed in…

Nowadays, the use of information technology (ICT) in education is nothing new. But the question is where the limit is when the use of ICT does not have the desired effect. In the paper we discuss the use of simulations in the teaching process that can positively influence students' achievements. At the beginning of the paper we present the results…

A pair of objects on an inclined plane are connected together by a string. The upper object is then connected to a fixed post via a spring. The situation is first analysed as a classroom exercise in using free-body diagrams to solve Newton's second law for a system of objects upon which many different kinds of force are acting (string tension,…

The concept of "perpetual motion" has a long history. The Indian astronomer and mathematician Bhaskara II (12th century) was the first person to describe a perpetual motion (PM) machine. An example of a 13th-century PM machine is shown in Fig. 1. Although the law of conservation of energy clearly implies the impossibility of PM construction, over…

Experiments with an electric motor provide good opportunity to demonstrate some basic laws of electricity and magnetism. The aim of the experiments with a low-power dc motor is to show how the motor approaches its steady rotation and how its torque, mechanical power and efficiency depend on the rotation velocity. The tight relationship between the…

Early in the last century, Robert Millikan developed a precise method of determining the electric charge carried by oil droplets. Using a microscope and a small incandescent lamp, he observed the fall of charged droplets under the influence of an electric field inside a small observation chamber. In so doing, Millikan demonstrated the existence of…

The implementation of an automated system based on the hot-wire technique is described for the measurement of the thermal conductivity of liquids using equipment easily available in modern physics laboratories at high schools and universities (basically a precision current source and a voltage meter, a data acquisition card, a personal computer…

The introduction of teaching about liquid crystals is discussed from several points of view: the rationale why to teach them, the basics about liquid crystals or what the teacher should teach about them, the fundamental pre-knowledge of students required, the set of experiments accompanying the teaching and the brief report on the already…