Bacteria have developed a cell-to-cell communication system called quorum sensing (QS), allowing them to regulate group behavior and synchronize the expression of virulence factors, responsible for increasing their infection capacity and resistance to antimicrobials. Although the control of microbial infections through the inhibition of microbial…

In undergraduate science education, laboratory courses stand as essential cornerstones of experiential learning. Chemistry laboratory courses offer students unique hands-on experiences that bridge the gap between theoretical knowledge and practical application. The journey through the undergraduate chemistry curriculum is paved with a series of…

Nitrate is a crucial parameter for assessing water quality, owing to its dual function in ecological systems. These functions can be beneficial or detrimental depending on whether nitrate concentrations are low or high, respectively. The ultraviolet spectrophotometric method (standard as 4500-NO[subscript 3]--B) is a classic method for determining…

This study uses two different approaches to examining student outcomes and understanding in the context of aspects of acid-base chemistry. It introduces the use of evidence centered assessment design as a design framework of a multi-dimensional acid-base titration laboratory and as an analysis tool of student performances in a lab setting and in…

Over the past 20 years research on reform efforts aimed at the chemistry laboratory has focused on different aspects of students' experiences including increasing content knowledge, improving student attitudes toward chemistry, incorporating inquiry activities, and providing students a hands-on experience related to the chemistry concepts learned…

The physical science curriculum design at Georgia Gwinnett College requires a theme-based course (lecture and group work, and laboratory) for nonscience majors. Increased student engagement is anticipated when science topics are taught in the context of a topic of which students can select during course registration. This paper presents the course…

Contribution: There are many on-line resources available to learn about optics and photonics, but no assessment tools exist to evaluate the learning achievements. This paper presents an assessment framework whose validity has been proven on a course with over 70 engineering students. Background: There is evidence that on-line resources complement…

This paper presents an analysis of the scientific reasoning of a dyad of secondary school students about the phenomenon of dissolution of gases in water as they work on this in a simulated laboratory experiment. A web-based virtual laboratory was developed to provide learners with the opportunity to examine the influence of physical factors on gas…

We propose a simple and fascinating experiment for studying diffusion in gels using a pH-sensitive dye. By doping agar with methyl red, we obtain a gel which rapidly reacts to changes in pH by changing its absorption spectrum. The pH gradients can be followed using a digital camera, and we demonstrate here that the pH-sensitive colour changes can…

Every student who studies atmospheric pressure in physics or chemistry learns the principles behind the construction of barometers. Cistern barometers, such as those found in most laboratories, consist of a long glass tube containing an inverted column of liquid having an open end in a cistern of the liquid. Students learn that the column of…

This paper reports on a case study of an immersive and integrated multi-instructional approach (namely computer-based model introduction and connection with content; facilitation of individual student exploration guided by exploratory worksheet; use of associated differentiated labs and use of model-based assessments) in the implementation of…

An internal standard method applicable to undergraduate instrumental analysis or environmental chemistry laboratory has been designed and tested to determine the Henry's law constants for a series of alkyl nitriles. In this method, a mixture of the analytes and an internal standard is prepared and used to make a standard solution (organic solvent)…

This article describes the principles, applications and performances of methods to measure gas-phase air pollutants that either utilise passive or active sampling with subsequent laboratory analysis or involve automated "in situ" sampling and analysis. It focuses on air pollutants that have adverse impacts on human health (nitrogen…

Recent emphasis on the science of food and cooking has been observed in our popular literature and media. As a result of this, a new non-science majors course, The Science of Food and Cooking, is being taught at our institution. We cover basic scientific concepts, which would normally be discussed in a typical introductory chemistry course, in the…

We show that the treatment of pendulum movement, other than the linear approximation,may be an instructive experimentally based introduction to the physics of non-linear effects. Firstly the natural frequency of a gravitational pendulum is measured as function of its amplitude. Secondly forced oscillations of a gravitational pendulum are…