Author Archives: dcashman

Introduction The experiment demonstrates the interactions between hydrophobic and hydrophilic substances. Hydrophobic substances repel water – the name comes from the Greek word, “Hydros”, for water, and, “phobos”, for fear. Hydrophilic substances (the Greek stem, “philic”, means “love”) attract, or … Continue reading →

Introduction Multi-colored slime can be created using a solution of poly-vinyl alcohol (PVA) and borax. This experiment demonstrates the ability of borax to form chemical cross-links between molecules of the PVA polymer. The chemical structures below show a molecule of … Continue reading →

Introduction This is a fun demonstration that teaches students how to build simple molecular models using colored candies. It is relatively simple to prepare and set up, and easy to maintain. The basic principles of building small molecular models of … Continue reading →

Introduction This is a simple and fun, hands-on activity that demonstrates the basic concepts of computer-based molecular modeling. Using molecular mechanics, small molecules may be modeled by treating the atoms as balls and the bonds connected them as springs. We … Continue reading →

Introduction Some artists use the way paint moves on a surface to produce interesting shapes and designs. Many artists paint on a canvas, a type of fabric that is very absorbant. Before painting on canvas, most artists treat the surface … Continue reading →

Introduction The iodine clock reaction is a classical chemical clock demonstration that displays chemical kinetics in action. It was first discovered by Hans Heinrich Landolt in 1886, so many texts may refer to it as the Landolt Reaction. In this … Continue reading →