A different method to study the charging and discharging processes of a capacitor is presented. The method only requires a high impedance voltmeter. The charging and discharging processes of a capacitor are usually studied experimentally using an oscilloscope and, therefore, both processes are studied as a function of time. The approach presented…

Pre-recorded video demonstrations of laboratory experiments are used to introduce students to various experiments in a lab course instead of an in-class tutorial. In addition to saving time for both the students and the instructor, this allows students to watch the videos in an "on-demand" setting at their convenience, which is helpful…

The use of boric acid in the Kjeldahl determination of nitrogen is a variant of the original method widely applied in many laboratories all over the world. Its use is recommended by control organizations such as ISO, IDF, and EPA because it yields reliable and accurate results. However, the chemical principles the method is based on are not…

In this NSF-supported project, two Anasazi FT-NMRs are being integrated simultaneously across the chemistry curriculum at Western Kentucky University (WKU) and Elizabethtown Community and Technical College (ECTC). The collaborative project adds to a new curriculum initiative by integrating NMR throughout the chemistry curriculum to enhance both…

A watt balance is an electromechanical device that allows a mass to be determined in terms of measurable electrical and mechanical quantities, themselves traceable to the fundamental constants of physics. International plans are well advanced to redefine the unit of mass, the kilogram, in terms of a fixed numerical value for the Planck constant. A…

In Andhra Pradesh, India, chemical experimenting in under graduate college labs by students is neglected because most of the intermediate (10+1 and 10+2) students concentrate on writing competitive exams like EAMCET (Engineering and Medical Common Entrance Test), IIT JEE (Indian Institute of Technology Joint Entrance Test), AIEEE (All India…

An upper-division instrumental chemistry laboratory has been developed in which students use atomic force microscopy (AFM) to collect force curves on polydimethylsiloxane (PDMS) elastomers. Force curves are used to quantify the stiffness of elastomers prepared with different base-to-curing agent ratios. Trends in observed spring constants of the…

An undergraduate laboratory exercise is described to demonstrate the biochemical applications of electron paramagnetic resonance (EPR) spectroscopy. The beta93 cysteine residue of hemoglobin is labeled by the covalent binding of 3-maleimido-proxyl (5-MSL) and 2,2,5,5-tetramethyl-1-oxyl-3-methyl methanethiosulfonate (MTSL), respectively. The excess…

The essential oil of "Nepeta cataria" L. (catnip), an herbaceous plant known popularly as a stimulant for the domestic cat, is enriched in two diastereomeric iridoid lactones (nepetalactones) that vary in ratio. Although the diastereomers are chromatographically separable and exhibit different 1D NMR spectra, it is not possible to…

Drawing a schematic energy diagram for the decomposition of H[subscript 2]O[subscript 2] catalyzed by MnO[subscript 2] through a simple thermometric measurement outlined in this study is intended to integrate students' understanding of thermochemistry and kinetics of chemical reactions. The reaction enthalpy, delta[subscript r]H, is…

Production of thin metal oxide films was recently explored as part of an outreach program with a goal of producing nanoscale structures with household items. Household items coated with various metals or titanium compounds can be heated to produce colorful films with nanoscale thicknesses. As part of a materials chemistry laboratory experiment…

An undergraduate exercise in computational chemistry that investigates the energy barrier for pyramidal inversion of amines and phosphines is presented. Semiempirical calculations (PM3) of the ground-state and transition-state energies for NR[superscript 1]R[superscript 2]R[superscript 3] and PR[superscript 1]R[superscript 2]R[superscript 3] allow…

Modern undergraduate organic chemistry textbooks provide detailed discussion of stoichiometric Cr- and Mn-based reagents for the oxidation of alcohols, yet the use of such oxidants in instructional and research laboratories, as well as industrial chemistry, is increasingly avoided. This work describes a laboratory exercise that uses ambient air as…

Studio classrooms, designed such that laboratory and lecture functions can occur in the same physical space, have been recognized as a promising contributing factor in promoting collaborative learning in the sciences (NRC, 2011). Moreover, in designing for instruction, a critical goal, especially in the sciences and engineering, is to foster an…

A mixed-method quasi-experimental study was designed to determine how 130 undergraduates in an introductory astronomy survey course laboratory changed their understanding of scientific inquiry working as individuals in relative isolation compared to working in small, collaborative learning groups when using specially designed astronomy curricula…