A simple measurement of the refractive index of a liquid has been performed using a spherical lens. This lens is a spherical shape flask containing the liquid under study. Parallel pointer laser beams are directed to the lens to obtain the back focal length of the lens. The focal point is determined visually or using the Tracker software to…

Science and engineering students in the second semester of a calculus-based physics sequence typically study and measure the on-axis magnetic field for a multiple, circular turn coil. There are four benefits to this approach: 1) an analytical solution is easily obtained, 2) the coil is easily constructed using tightly wound, high-gauge wire where…

We present a simple experiment that allows us to demonstrate graphically that the intensity of sound waves is proportional to the square of their amplitude, a result that is theoretically analyzed in any introductory wave course but rarely demonstrated empirically. To achieve our goal, we use an audio signal generator that, when connected to a…

The question from the title is raised because in almost all introductory physics courses/textbooks the atmospheric pressure has been attributed to the weight of the column of air from a given level in the atmosphere up to its top. "Air is pressing on air." However the same textbooks, in the chapter on the kinetic theory of gases, tell…

The outbreak of COVID-19 pandemic results in the suspension of universities' academic laboratory activities. This brought a difficult time for graduate students majored in molecular biology and their mentors, since the student's thesis progress relies on the data from wet experiments in the lab. Even facing the challenges during the pandemic,…

General chemistry laboratory curriculum reform is underway at a midsized state university through a collaborative, inclusive, and iterative approach. Using a backward design approach, faculty collaborated to actualize a shared vision, define laboratory learning objectives, and outline considerations for inclusivity during summer workshops that…

Large, multisection laboratory courses are particularly challenging when managing grading with as many as 35 teaching assistants (TAs). Traditional grading systems using point-based rubrics lead to significant variations in how individual TAs grade, which necessitates the use of curving across laboratory sections. Final grade uncertainty…

Photoacoustic imaging is a state-of-the-art technique that combines light excitation with ultrasound generation via the photoacoustic effect. Since sound waves at clinically relevant frequencies undergo minimal perturbation as they pass through the body, photoacoustic imaging is ideal for deep-tissue imaging applications in vivo. Despite its…

A novel method of measuring the coefficients of kinetic and rolling friction is proposed. The method is simple to implement and reliable. Samples of measurements and calculations are presented.

Gas-phase nitrogen oxides are important in the formation of tropospheric ozone. NO[subscript x] (NO and NO[subscript 2]) as well as tropospheric ozone have been shown to have negative effects on human health. Therefore, accurately measuring NO[subscript x] concentrations in the atmosphere is important. In this laboratory experience, students…

This work describes a simple experiment to measure the resistor temperature as a function of the applied power and proves that it is an efficient way to introduce some important physical concepts in classroom, including the Joule's first law, hot-spot temperature, thermal resistance, thermal dissipation constant, time constant and the Newton's law…

The separation of chamazulene from hydrophilic contaminants present in blue tansy oil provides a visually engaging example of two common techniques: extraction and thin-layer chromatography (TLC). This application uses liquid CO[subscript 2] as a lipophilic solvent to pull a brilliant blue hydrocarbon molecule, chamazulene, out of or through a…

This laboratory experiment leverages the pedagogical value and multidisciplinary nature of biodiesel production from vegetable oil to introduce students to continuous-flow chemistry, a modern and rapidly growing approach to chemical synthesis. An interdisciplinary approach exposes students to the practical and conceptual aspects of modern…

Expensive, highly reflective barium sulfate plates are typically used to obtain solid-state UV-vis electronic spectra. Through normal laboratory use these plates become dirty, chip, and break, thus requiring replacement. An alternative to purchasing new plates is to make your own by combining a mechanical stabilizer, such as gum arabic, with…

Ever increasing technological progress opens novel opportunities concerning educational activities, and the ability to use the technology effectively is one of the 21st century's most demanding skills. The Partnership Forum for 21st-Century Skills (P21) states that no organization can achieve satisfying results without using technology and…