Discusses the use of the least-squares regression line in determining the optimum straight line in an efficient and objective manner and the validity of its underlying assumptions in certain situations. Discusses the treatment of kinetic data, distortion from large errors, and the Guggenheim method. (JRH)

Describes a laboratory exercise containing a practical series of experiments that novice students can perform within two hours. The exercise provides a confirmation of van't Hoff's law while placing more emphasis on osmotic flow than pressure. Students can determine parameters such as the reflection coefficient which stress the interaction of both…

Attempts to identify skills shown when able students work on open investigations. Findings indicate that these students use knowledge, carry out preliminary work, decide on objectives, are flexible, use a range of techniques, attempt to quantify, seek information from different sources, use time efficiently, report work, show critical appraisal of…

Presents the details of a waste treatment experiment that enables students to employ much of the chemistry they have learned in class to solve a real chemical problem. Heightens students' awareness of the potential environmental impact associated with the waste they have generated. Contains 21 references. (JRH)

Discusses ways in which datalogging equipment can enable titration curves to be measured accurately and how computing power can be used to predict the shape of curves. Highlights include sources of error, use of spreadsheets to generate titration curves, titration of a weak acid with a strong alkali, dibasic acids, weak acid and weak base, and…

Presents a laboratory procedure that involves students extracting their own DNA from a single hair follicle, using the polymerase chain reaction (PCR) to amplify a polymorphic locus, performing electrophoresis on the PCR products on an agarose gel, and visualizing the alleles to generate a "DNA fingerprint." Discusses theoretical background,…

Discusses simple and safe techniques that can be used in the educational laboratory to study hemoglobin. Discusses the spectral properties of hemoglobin, spectral-absorbence curves of oxyhemoglobin and carboxyhemoglobin, tracking the conversion of oxyhemoglobin to methemoglobin, and changing from the oxyhemoglobin to deoxyhemoglobin conformation.…

Describes open-ended experiments with seeds from the common garden radish (Raphanus sativus). The phases of the 5-E learning cycle--Engagement, Exploration, Explanation, Extension, and Evaluation--guide this activity series. (Author/MM)

A low-cost, low-tech colorimeter was constructed from a film canister. The student-constructed colorimeter was used to show the Beer-Lambert relationship between absorbance and concentration and to calculate the value of the molar absorptivity for permanganate at the wavelength emission maximum for an LED. Makes comparisons between this instrument…

If students are restricted to making educational experiments only, they might acquire incorrect ideas concerning the nature and role of the experimental method because the educational experiment differs greatly from the scientific experiment by its tasks, complexity, number and variability of experiments and devices used, measurements, and…

Students compare several different window cleaner recipes to determine the purpose each ingredient serves, then develop their own "New and Improved" recipe to test its performance against commercial window cleaner. Complements the National Chemistry Week 2002 theme, "Chemistry Keeps Us Clean." (Author/MM)

Describes four kinds of movement by a cat with or without angular momentum and tail or tail-less during free falling. Presents many pictures illustrating the movement. Supports the position that the angular momentum of the tail plays an important role in free fall. (YP)

Questionnaires from students passing the General Certificate of Secondary Education (GCSE) that explored attitudes to dissection and using animals in product testing administered to (n=469) students ages 14-15 showed a high level of support for peers who object to dissection, although objectors are likely to be met with derogatory comments,…

Presents an activity in which college chemistry students collaboratively identify chemical substances. (MKR)

Focuses on the provision of meaningful counterintuitive experimental evidence for students while taking into account the relations of theory, instruments, and experimental data. Discusses the use of experiments designed to test pupils' conceptual framework during the teaching of introductory electricity. (JRH)