Various sequences for teaching genetics have been proposed. Three seventh-grade biology textbooks in Taiwan share similar key knowledge assemblages but have different knowledge arrangements. To investigate the influence of knowledge arrangements on student understanding of genetics, we compared students' reading comprehension of the three texts…

Evaporation and boiling are both terms applied to the change of a liquid to the vapour/gaseous state. This article argues that it is the formation of bubbles of vapour within the liquid that most clearly differentiates boiling from evaporation although only a minority of chemistry textbooks seems to mention bubble formation in this context. The…

Using the life sciences, this article first reviews essential features of the "NRC Framework for K-12 Science Education" that provided a foundation for the new standards. Second, the article describes the important features of life science standards for elementary, middle, and high school levels. Special attention is paid to the teaching…

Anthocyanins are a class of pigments responsible for the bright colors of many flowers, fruits, and vegetables typically resulting in shades of red, blue, and purple. Students were asked to perform an activity to enable them to identify which anthocyanin was present in one of several possible plant materials through a hands-on activity. Students…

The purpose of this study was to analyze and compare the alternative conceptions of high school students and preservice teachers on the concept of atomic size. The Atomic Size Diagnostic Instrument was developed; it is composed of eight, two-tier multiple-choice items. The results of the study showed that as a whole 56.2% of preservice teachers…

The relationship between the structure and function of proteins is an important area in biochemistry. Pupils studying A-level Biology are introduced to the four levels of protein structure (primary, secondary, tertiary and quaternary) and how these can be used to describe the progressive folding of a chain of amino acid residues to a final,…

An eight-session interdisciplinary laboratory curriculum has been designed using a suite of analytical chemistry techniques to study biomaterials derived from an inexpensive source such as the tomato fruit. A logical progression of research-inspired laboratory modules serves to "tour" the macroscopic characteristics of the fruit and the…

A visual demonstration of the difference between hydrophilic and hydrophobic surfaces has been developed. It involves placing a shadow mask on an optically clear hydrophobic plastic dish, corona treating the surface with a modified Tesla coil, removing the shadow mask, and visualizing the otherwise invisible message or pattern by applying water,…

A proposal to define the oxidation state of an atom in a compound as the hypothetical charge of the corresponding atomic ion that is obtained by heterolytically cleaving its bonds such that the atom with the higher electronegativity in a bond is allocated all electrons in the bond. Bonds between like atoms are cleaved homolytically. This…

When the LHC started running at the end of March 2010--after a 14-month shutdown for major repairs--one of the main objectives was reaching a luminosity of 10[superscript 32] cm [superscript -2] s [superscript -1] by the end of 2010. On 13 October 2010 that goal was achieved. One important parameter to take into account to reach this luminosity is…

This work comprises an investigation about basic Quantum Mechanics (QM) teaching in the high school. The organization of the concepts does not follow a historical line. The Path Integrals method of Feynman has been adopted as a Reference Conceptual Structure that is an alternative to the canonical formalism. We have designed a didactic sequence…

A laboratory inquiry into the thermochemical relationships in the reaction between aqueous solutions of NaHCO[subscript 3] and NaOH is described. The enthalpy change for this reaction, delta[subscript r]H, and that for neutralization of strong acid and NaOH(aq), delta[subscript n]H, are determined calorimetrically; the explanation for the…

Visualizing molecular properties is often crucial for constructing conceptual understanding in chemistry. However, research has revealed numerous challenges surrounding students' meaningful interpretation of the relationship between the geometry and electrostatic properties of molecules. This study explored students' (n = 18) use of three visual…

The performance of a fan is usually estimated using hydrodynamical considerations. The calculations are long and involved and the results are expressed in terms of three affinity laws. In this paper we use kinetic theory to attack this problem. A hard sphere collision model is used, and subsequently a correction to account for the flow behaviour…

Molecular visualizations have been widely endorsed by many chemical educators as an efficient way to convey the dynamic and atomic-level details of chemistry events. Research indicates that students who use molecular visualizations are able to incorporate most of the intended features of the animations into their explanations. However, studies…