Crystal Structures

Chemistry is a subject in which high-school and university students must learn the structure and properties of atoms and molecules. This cannot be done without an appreciation of their spatial characteristics. Presenting the information in an interactive 3D context can alleviate many of the problems.

The structures adopted by many crystals can be understood in terms of the symmetry of the structures and the different ways in which collections of spheres can be stacked. Both of these concepts create problems for students because their proper understanding requires the student to visualise and manipulate 3D images in their minds. The Crystal Structures demo allows students to build-up models of increasing complexity, making it easy to learn the characteristic spatial features. The interactivity offered by the Istya framework makes it possible to display or hide key features so that the student can concentrate on these and learn to see them in the context of the overall structure.

The demo shows how information can be derived from studying the external shapes of crystals. This develops a basic awareness of symmetry properties and symmetry operations. Thereafter it is shown how the structures of hundreds of different crystals can be traced to simple variations in the stacking of spheres of different sizes. Each section of the demo addresses a different age group, to show how the information might be presented. It ends with information suitable for university research students.