Dilute guarana´ ("Paullinia cupana") powder aqueous extract is a soft drink that contains three structurally related methylxanthines (MXs), caffeine (CF), theobromine (TB), and theophylline (TP); CF is present in a large excess. Literature data show that values of [lambda][subscript max] and [epsilon][subscript max] of these three MXs…

Frozen peas and carrots are commonly available in grocery stores in the United States. The carrots are cut into cubes roughly 8 mm on a side, while the peas are roughly spherical with a diameter of about 6 mm. They are prepared together in water that is brought to a boil. The peas and carrots, which are initially mixed together, separate as the…

White light refracted by a glass edge or a prism might be split into the colors of the rainbow but, when restricted by a suitable arrangement of edges, might also yield a sequence of colors complementary to the rainbow. We studied the creation of these color fields experimentally with a setup consisting of RGB light-emitting diodes that cover all…

We investigated potential drivers of interest in topic-context and topic-activity combinations, as well as interactions between the different elements of situational interest in evolutionary biology. High school students (n = 982, age 17 years) were asked to rate their interest in two sets of items consisting of topic-context and topic-activity…

Despite extensive conceptualization of ions as hard spheres in most textbooks, solid-state structures are more accurately modeled as overlapping soft spheres that better reflect the size of the ions. The corresponding soft-sphere ionic radii of alkali and halide ions can be empirically established from the partial molar volume of the ions in…

One particular challenge in chemistry learning is developing students' atomic level understanding of chemical processes. It is necessary to help students learn how to critique atomic models rather than accept them as ''truth.'' In this study, we used a resources-based framework to examine how students made sense of macroscopic level information to…

In the museum wing of the Greenslade house is a clock with a two-second pendulum about one meter long. This ticks once per second, and every time it passes through dead center it completes an electrical circuit. When I came to Kenyon in 1964, this system was used to send signals to a series of telegraph relays, which ticked once per second.…

The inhibition of porcine pancreatic lipase by the drug orlistat was studied through a series of activities that combine experimental and computational procedures. The enzymatic activity of the lipase was determined by measuring enzyme kinetics and calculating parameters such as K[subscript m] and V[subscript max] from experimental data. Assays of…

This paper reports the first empirical investigation of the hypothesis that epistemic appraisals form part of the structure of concepts. To date, studies of concepts have focused on the way concepts encode properties of objects and the way those features are used in categorization and in other cognitive tasks. Philosophical considerations show the…

The experimental investigation of Newton's law of universal gravitation requires expensive and sensitive equipment. Therefore, it is often not possible to conduct such an experiment within a typical physics class. An alternative is to investigate the universal gravitation law by using simulations. In this paper, we are presenting such an augmented…

The history of particle physics can be considered nothing less than a huge triumph for science. Over the course of a little more than a century of effort, our understanding of the world of atomic and subatomic physics went from a vague understanding of atoms, to one that is much more detailed. Early in this hundred-year-long period, we learned…

This study focuses on the experimental demonstration of the definition of kelvin using a triple point of water (TPW) cell and estimates the measurement uncertainty. The first part of this article is to construct the measurement setup and perform the measurements. The second stage is related with the calculation of uncertainty according to guides…

The fundamental mechanism of biochemistry lies on the reaction kinetics, which is determined by the reaction pathways. Interestingly, the reaction pathway is a challenging concept for undergraduate students. Experimentally, it is difficult to observe, and theoretically, it requires some degree of physics knowledge, namely statistical and quantum…

Obtaining adequate understanding of scientific concepts is considered challenging due to learners' misconceptions about natural phenomena. Misconceptions may coexist with scientific knowledge in the brain. Therefore, misconceptions must be cognitively inhibited in order to select the scientific knowledge. There is, however, lack of substantial…

Space-time plays a central role in the scientific study of learning trajectories. From a sociocultural perspective, the definition of a set of space-time coordinates enables researchers to identify and examine both the learning activities in which subjects participate and those life events relevant to understanding their learning processes. The…