Electrophilic aromatic substitution (S[subscript E]Ar) and nucleophilic aromatic substitution (S[subscript N]Ar) reactions are among the most valuable reactions in the conversion of aromatic rings. While these reactions are typically covered in separate experiments in undergraduate organic courses, a continuous experimental setup elucidating both…

Photochemical reactions are initiated by the absorption of light, triggering the chemical reactions and resulting in the formation of products. These reactions are generally performed using a freely available renewable source of energy-solar energy. Solar simulators mimic both the ultraviolet and visible regions of sunlight and hence can serve as…

We investigated a very long chain falling from the pile on the edge of a table to the floor both experimentally and theoretically. In this very simple and novel configuration we showed that the velocity of the chain quickly converges to its asymptotic value, and that the steady-state velocity is proportional to the square root of the height of the…

Electrochemistry is taught in most undergraduate chemistry programs. Although this topic is important for students due to its broad interest in industry (energy, diagnostics, car industry, etc.), they often find it difficult, because it is based on a combination of various physical concepts such as electric fields, interfacial processes or charge…

The interference pattern between two harmonic oscillations with slightly different frequencies are called beats. The beats, as a combined motion, have two different periods, one approximately equal to the period of the original oscillations, and another that is significantly longer and is related to the variable amplitude of the motion. The main…

A procedure to purify anthocyanin, a natural pigment, following a green approach by using macroporous resin and its encapsulation for the maintenance of its stability is described. This laboratory experiment, which describes the benefits of using resin for the purification, is a learning tool for students working in the field on nutraceuticals.…

A loop-the-loop experiment is described to show how sliding friction affects motion of the ball. Conservation of energy can be used to explain the basic physics, but significant energy loss is observed in practice and expands the usefulness of this apparatus as a teaching tool.

For single-slit diffraction and double-slit interference experiments, commercially made slits can be the most expensive parts, especially since the prices of laser pointers have become very low. One option is to use a razor blade to cut slits in either paint or electrical tape on microscope slides. However, this takes practice, and there is some…

Student misconceptions of the double-slit experiment (Fig. 1) are abundant. The most common ones that we observe include: (1) belief that constructive interference requires both pathlengths to be integer multiples of the wavelength ("L[subscript 1] = n[subscript 1][lambda]" and "L[subscript 2] = n[subscript 2][lambda]") rather…

The conical pendulum is a classic introductory physics problem for teaching circular motion--a topic about which students frequently carry alternative conceptions. As teachers provide lessons to untangle these conceptions, it is good to allow students to practice their new knowledge in varied settings. This is one possible experiment that builds…

As an introduction to sound and vibration, the authors wanted their first-grade students to plan and conduct their own investigations. In this article, the authors share a series of investigations to help students explore the relationship between sound and vibration. By planning, creating, testing, adapting, and reflecting on the outcomes of the…

Experimental results are presented concerning a bead sliding on a rotating, horizontal rod. If the rod rotates at constant angular velocity then the sliding speed in the radial direction increases exponentially with time, provided that the rotation speed is sufficient to overcome friction. Otherwise the bead rotates in a circular path of constant…

A simple experimental setup using a smartphone and a pair of speakers is presented to perform an accurate experiment on interference of two point sources. The proposed experiment allows simple but interesting measurements to be done to introduce students to interference and diffraction phenomena. As such, the experiment effectively introduces the…

The laser pointer has been widely used to demonstrate some simple optics phenomena, like reflection, refraction, total reflection, and diffraction. However, the rays of laser light cannot be seen in the air because the scattered light is too weak. Many physics teachers use milk or smoke to visualize rays of laser light in physics labs, but it is…

Frozen peas and carrots are commonly available in grocery stores in the United States. The carrots are cut into cubes roughly 8 mm on a side, while the peas are roughly spherical with a diameter of about 6 mm. They are prepared together in water that is brought to a boil. The peas and carrots, which are initially mixed together, separate as the…