Lakes are artists' pigments made from colorants bound to an inert substrate, usually hydrated aluminum oxide. Before the late 19th century, lakes were made from natural pigments extracted from plants and insects, extracted either directly from the dyestuff or indirectly from waste materials generated in the manufacture of dyed textiles. The first…

In this article, we discuss the replication of a forgotten chemical instrument in the context of undergraduate chemistry education. Together with students, we have attempted to replicate an eighteenth century "eudiometrical" procedure. Eudiometry was the practice of measuring the "goodness" of the air by looking at the volume…

Fluorescence-related experimental techniques play an important role in biochemistry, molecular biology, and cell biology. However, fluorescence-related experiments are rarely included in the laboratory courses of most Chinese universities. This is mainly due to the conflict between large class size (50-60 students in one room) and funding/space…

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…

The study aimed to determine the effects of students teams achievement divisions (STAD) and reading-writing-application (RWA) methods on teacher candidates' academic achievements, laboratory attitudes, cooperative work, laboratory safety and scientific process skills in science teaching laboratory practice-I courses. In the research, a…

Adsorption studies of salicylic acid (SA) and 4-nitroaniline (4NA) from aqueous solutions were performed with magnetic biochar (MBC) in order to train students in analytical techniques such as standard calibration curves, UV-vis spectrophotometry, and chemical separations within the context of wastewater purification. Analysis of samples purified…

The human nose is a very sensitive detector and is able to detect potent aroma compounds down to low ng/L levels. These levels are often below detection limits of analytical instrumentation. The following laboratory exercise is designed to compare instrumental and human methods for the detection of volatile odor active compounds. Reference…

Research-based learning motivates students to identify with different subjects. The orientation program MINTgrün at Technische Universität Berlin offers two study semesters for open choices of teaching modules, including a series of specially designed laboratories covering topics like robotics, construction, environmental research, programming,…

A diffusion cell to model the permeation of salicylate drugs through the skin using low-cost materials and a sensitive colorimetric analytical technique is described. The diffusion apparatus has been used at a further education college by a student for her AS-level Extended Project to investigate the permeation rates of salicylic acid…

We present a practical activity focusing on two main goals: to give learners the opportunity to experience how the scientific method works and to increase their knowledge about enzymes in everyday situations. The exercise consists of determining the amylase activity of commercial detergents. The methodology is based on a qualitative assay using a…

Students commonly test the effects of chemical agents on the heart rate of the crustacean "Daphnia" magna, but the procedure has never been optimized. We determined the effects of three concentrations of ethanol, nicotine, and caffeine and of a control solution on heart rate in "Daphnia." Ethanol at 5% and 10% (v/v) reduced mean heart rate to…

A simple procedure for the isolation of the cholesterol, by hydrolysis and extraction followed by column chromatography, is described. The cholesterol can be further purified by complexation with oxalic acid. It can also be oxidized and conjugated to cholestenone. The source of the cholesterol is one egg yolk, which contains about 200 mg of…

A reality show about a college course--a chemistry class no less? That's what "ChemLab Boot Camp" is. The 14-part series of short videos is being released one episode at a time on the online learning site of the Massachusetts Institute of Technology. The novel show follows a diverse group of 14 freshmen as they struggle to master the…

Cleaning erasers are used to support methanol-fueled flame tests. This safe demonstration technique requires only small quantities of materials, provides clean colors for up to 45 seconds, and can be used in the classroom or the auditorium. (Contains 1 note.)

We consider a volume of air trapped over a glycerol column in a eudiometer. We demonstrate that there is an approximately linear relationship between the volume of trapped air and the height of the glycerol column. Simply by moving the eudiometer up and down, we cause the glycerol-column height and trapped-air volume to vary. The plot of volume…