String theory and the real world: the visible sector, 2nd edition

Abstract

exploration. Only in the very last activity on digital electronics is there an open challenge presented to the students. Missing is a short review of uncertainties and least squares fitting of linear functions. This despite a majority of activities directing the students to use Excel to obtain a best fit linear approximation to the ‘data points’. A short guide to the PhET simulation on least squares regression would have been a valuable addition. An important question is whether the text provides added value compared to the descriptions accompanying the PASCO experimental kits. Unfortunately, it seems that in his endeavour to make the simulation procedures as close as possible to what a student might experience with the equivalent Pasco kit, Professor Erenso has, at least in some cases, somewhat curtailed the ‘real’ activity. A pertinent example is the activity on resistors and Ohm’s law. The text guides the student in making current versus voltage drop measurements on a single resistor connected to a variable power supply, a task which is also easy to simulate in one of the PhET modules. The equivalent Pasco activity directs the student to also make measurements by replacing the resistor with an incandescent light bulb and a semiconductor diode. The student is then invited to consider why the light bulb despite being essentially a metallic filament does not obey a linear Ohm’s relation (and is of course much harder to simulate). Although it goes against themain premise of providing essentially equivalent virtual and real tracks that can be switched easily, one could argue that a more fruitful approach would be to leverage the strengths of virtual simulations to emphasise the key concepts and explore the relationship between the relevant experimental parameters as a pre-lab activity. Then building on this foundation, more open-ended experimental challenges could be proposed in the laboratory and the limits imposed by experimental uncertainty or unjustified idealizations could be explored. Finally, perhaps due to the sense of urgency provoked by the pandemic, when many students were locked out of the teaching laboratories, there are a few flaws in this first edition. The resolution of themajority of figures illustrating the virtual labs is low – they appear to be cropped screenshots. Several misprints are present. Given the simulations’ prominence, it is curious that the PhET project is often referred to as PhTH, while the University of Colorado at Boulder has been relocated to ‘at Boulevard’. More troubling is some confusion about the time-dependent Schrödinger equation in the introduction to atomic physics. Also, the theory presented is limited to describing the gross energy structure of the hydrogen atom. Because angular momentum is ignored, the virtual activity specifies, without justification, that the Bohr model should be used instead of the Schrödinger prediction which might reinforce common misconceptions about atomic electron orbits. In summary, if an instructor is looking for a set of experimental activities that can be readily switched at will from in-person to virtual, this is a book worth considering for an algebra-based introductory course covering simple optics, early modern physics and electronics. If the Pasco kits are available, little effort would be required to implement the experimental programme. However, by choosing to provide parallel virtual and real activities, the synergies and reinforcement that could be accessed through a more complementary approach are lost.