In this exercise, students apply a combination of techniques to investigate the impact of metal identity and ligand field strength on the spin states of three d[superscript 5] transition-metal complexes: Fe(acac)[subscript 3], K[subscript 3][Fe(CN)[subscript 6]], and Ru(acac)[subscript 3], where acac[superscript -] is acetylacetonate. Students…

In this paper I report a lengthy episode from a teaching experiment in which 15-Year 12 Greek students negotiated their definitions of tangent line to a function graph. The experiment was designed for the purpose of introducing students to the notion of derivative and to the general case of tangent to a function graph. Its design was based on…

In this article we propose a hands-on experimental activity about predator-prey interactions that can be performed both in a research laboratory and in the classroom. The activity, which engages students in a real scientific experiment, can be explored not only to improve students' understanding about the diversity of anti-predator behaviors but…

The acid ionization constant, K[subscript a], of acetic acid and the base ionization constant, K[subscript b], of ammonia are determined easily and rapidly using a datalogger, a pH sensor, and a conductivity sensor. To decrease sample preparation time and to minimize waste, sequential aliquots of a concentrated standard are added to a known volume…

In this experiment students are exposed to concepts in inorganic synthesis and various spectroscopies as applied to a tri-tungsten cluster with applications in biomedical imaging. The tungsten-acetate cluster, Na[W[superscript 3](mu-O)[subscript 2](CH[superscript 3]COO)[superscript 9]], 1, was synthesized and characterized by [superscript 1]H-NMR,…

X-ray fluorescence (XRF) data from an energy-dispersive XRF instrument were used to investigate the chlorine K[alpha] and K[beta] peaks in several group 1 salts. The ratio of the peak intensity is sensitive to the local chemical environment of the chlorine atoms studied in this experiment and it shows a periodic trend for these salts. (Contains 1…

Although the siphon has been in use since ancient times, the exact mechanism of operation is still under discussion. For example, most dictionaries assert that atmospheric pressure is essential to the operation of a siphon rather than gravity. Although there is general agreement that gravity is the motivating force in a siphon, there is…

To diversify the measurement techniques of Avogadro's number in physics teaching, I propose a simple acoustic method for the experimental determination of Avogadro's number based only on the measurement of the speed of sound in metals, provided that their Debye temperatures are known. (Contains 2 figures.)

A simple wind speed measurement device, a paper anemometer, is fabricated based on the theory of standing waves. In providing the working profile of the paper anemometer, an experimental device is established, which consists of an anemometer sensor, a sound sensor, a microphone, paper strips, a paper cup, and sonic acquisition software. It shows…

Two experiments using a sentence recall task tested the effect of animacy on syntactic processing in Japanese sentence production. Experiment 1 and 2 showed that when Japanese native speakers recalled transitive sentences, they were more likely to assign animate entities earlier positions in the sentence than inanimate entities. In addition,…

This experiment describes a method for cyclohexene oxidation to "trans"-1,2-cyclohexanediol using "p"-toluenesulfonic acid ("p"-TsOH) as promoter and hydrogen peroxide as oxidant in a biphasic system. This method allows conversions up to 97.9% (monitored by [superscript 1]H NMR). "trans"-1,2-Cyclohexanediol was not easily separated from the…

The siphon is a very useful example of early technology, the operation of which has long been well understood. A recent article makes the claim that established beliefs regarding this device are incorrect and proposes a "chain model" in which intermolecular forces within the fluid play a large role while atmospheric pressure does not. We have…

A concurrent-chains procedure was used to examine choice between segmented (two-component chained schedules) and unsegmented schedules (simple schedules) in terminal links with equal inter-reinforcement intervals. Previous studies using this kind of experimental procedure showed preference for unsegmented schedules for both pigeons and humans. In…

Seventy students participated in an experiment to measure the effects of either providing explanations or listening during small group discussions on recall of related subject-matter studied after the discussion. They watched a video of a small group discussing a problem. In the first experimental condition, the video was stopped at various points…

I advance some novel arguments for the use of historical experiments in science education. After distinguishing three different types of historical experiments and their general purposes, I define "complementary experiments", which can recover lost scientific knowledge and extend what has been recovered. Complementary experiments can help science…