Conventional mobile phone colorimetry usually utilizes the RGB color mode to measure concentration of solutions, but the paper entitled "Determining the Amount of Copper(II) Ions in a Solution Using a Smartphone" proposes the use of hue ("H") to measure the concentration. It is pointed out that the "H" value increases…

The double-indicator method is often used in the analysis of Na[subscript 2]CO[subscript 3], NaHCO[subscript 3], and NaOH mixtures (carbonate mixtures). In this method, the determination of the volumes at the first and second equivalence points plays a crucial role in analyzing the composition and content of the carbonate mixtures. Here, LabVIEW…

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…

An experiment is described where a billiard ball and a golf ball were projected with backspin on a horizontal surface to measure the transition from sliding to rolling. During both phases, the torque on the ball is affected by an offset in the line of action of the normal reaction force.

Neutrinos are perhaps the least understood of the known denizens of the subatomic world. They have nearly no mass, interact only via the weak nuclear force and gravity, and, perhaps most surprising, the three known species of neutrinos can transform from one variant into another. This transformation, called neutrino oscillation, has been…

A simple experiment is described to compare the descent time between two vertically separated points when an object slides down tracks of varying shape. A surprising result is that the descent time is shortest when it follows a circular track rather than a cycloidal track. Cycloidal tracks are usually predicted to result in the shortest descent…

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.

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…

A smartphone magnetometer is used to record the magnetic field of a freely falling point dipole magnet. The recorded magnetic field vs. time data are analyzed in accordance with the spatial dependence of the magnetic field to calculate the acceleration due to gravity g. The experiment gives local g to be 9.79 ± 1.9% m/s[superscript 2].

An experiment is described where a pendulum bob was allowed to roll back and forth across an inclined plane. The period of oscillation is larger than that for oscillation in a vertical plane, in part because the effective value of "g" is reduced on an inclined plane. The experiment highlights the differences between all three common…

Cell size is an important variable in the study of cellular growth, metabolism, and the cell cycle. The large size of "Amoeba proteus" and the ease with which it can be collected and cultured have made it a star in biology education--and it was a model for research on cell biology before the introduction of molecular genetic methods.…

A solar eclipse provides a well-characterized reduction in solar radiation. Solar radiation is a driving factor in meteorological and climate models. Hence, solar eclipses provide a unique opportunity to do large-scale meteorological experiments by measuring the effects on temperature, pressure, and wind while the atmospheric conditions stay…

This manuscript describes a laboratory exercise that allows students to use conductive atomic force microscopy (CAFM) for the analysis of electrodeposited, metallic structures. In addition to nanoscale electrical characterization with CAFM, this laboratory exercise also provides students with an opportunity to explore nanofabrication by…

We have developed a stereo vision system for observing real objects for experimental physics demonstration. The stereo vision observes objects from two different points of view. An observer can identify the distance and velocity of an object based on at least two different points of view. This paper demonstrates our comprehensive observation in a…

A cost-effective method has been developed with utmost efficiency for the determination of density of a liquid. The experimental setup for this purpose is a Polyvinyl chloride (PVC) cylinder fitted with an overflow spout, a volume measuring cylinder, a wooden block along with a hook and a known mass taken from scientific weight box. For this…