Dark matter makes up most of the matter in the universe but very little of a standard introductory physics curriculum. Here we present our construction and use of a spandex sheet-style gravity simulator to qualitatively demonstrate two aspects of modern physics related to dark matter. First, we describe an activity in which students explore the…

Thin film interference manifests itself in a wide range of visually pleasing situations in everyday life (in the colored effects caused by a drop of oil on water, in soap bubbles, etc.) and is also involved in important technical applications (semi-reflecting mirrors, anti-reflection lenses, etc.). Yet, despite its familiarity, high school…

A contemporary approach to the synthesis and purification of several UV-active dipeptides has been developed for the second-year organic laboratory. This experiment exposes students to the important technique of solution-phase peptide synthesis and allows an instructor to highlight the parallel between what they are accomplishing in the laboratory…

When conducting experiments involving the measurement of physically related quantities, choosing an appropriate spacing for the experimental independent variable is a crucial procedure whose consequences may go beyond data graphical visualization. This is particularly true if the measured quantities are nonlinearly related and experimental errors…

An operationally simple, reliable, and cheap Sonogashira reaction suitable for an undergraduate laboratory class that can be completed within a day-long (8 h) laboratory session has been developed. Cross-coupling is carried out between 2-methyl-3-butyn-2-ol and various aryl iodides using catalytic amounts of bis(triphenylphosphine)palladium(II)…

The reductive amination reaction between an amine and an aldehyde or ketone is an important method to add an additional alkyl group to an amine nitrogen. In this experiment, students react a selection of benzylamines with aldehydes to form the corresponding imines. These imines are reduced with a mixture of "p"-toluenesulfonic acid…

Twenty-two hundred years ago, the Greek scientist Eratosthenes measured the circumference of the Earth. This paper describes an experiment to replicate Eratosthenes' experiment with observers located in Australia and New Zealand. The most accurate circumference produced in the experiment described in this paper is 38,874?km, measured at Rosebud,…

Chemical separations are an important part of an undergraduate chemistry curriculum. Sophomore students often get experience with liquid-liquid extraction in organic chemistry classes, but liquid-liquid extraction is not as often introduced as a quantitative sample preparation method in honors general chemistry or quantitative analysis classes.…

Reformed experimental activities (REActivities) are an innovative approach to the delivery of the traditional material in an undergraduate organic chemistry laboratory. A description of the design and implementation of REActivities at both a four- and two-year institution is discussed. The results obtained using a reformed teaching observational…

The purpose of this study is to explore factors that affect exclusively physical, virtual and both a Virtual-Physical (VP) and Physical-Virtual (PV) sequence of manipulatives within Studio Physics environment. In this environment students actively work together to learn through real world experimentation and simulation based activities. Activities…

Every instructor should know some easy examples of anharmonic oscillations. The rocking of an empty wine bottle or a slender beer glass is one of those: The angle is not a sinusoidal function of time and the period is not independent of the amplitude, not even for small amplitudes. But care has to be taken that the glass does not slip or rotate…

Electrochemistry is a significant area of analytical chemistry encompassing electrical measurements of chemical systems. The applications associated with electrochemistry appear in many aspects of everyday life: explaining how batteries work, how the human nervous system functions, and how metal corrosion occurs. The most common electrochemical…

In April 1820, Hans Christian Ørsted noticed that the needle of a nearby compass deflected briefly from magnetic north each time the electric current of the battery he was using for an unrelated experiment was turned on or off. Upon further investigation, he showed that an electric current flowing through a wire produces a magnetic field. In 1831…

In nature, water drops can have a large variety of sizes and shapes. Small droplets with diameters of the order of 5 to 10 µm are present in fog and clouds. This is not sufficiently large for gravity to dominate their behavior. In contrast, raindrops typically have sizes of the order of 1 mm, with observed maximum sizes in nature of around 5 mm in…

In a recent paper, Zable described an experiment with a near-spherical balloon filled with impure helium. Measuring the temperature and the pressure inside and outside the balloon, the lift of the balloon, and the mass of the balloon materials, he described how to use the ideal gas laws and Archimedes' principal to compute the average molecular…