Forging Chemical Connections among the Symbolic, Macroscopic, and Microscopic Realms: Getting Students to Visualize and Understand Using Technology Scott A. Sinex Barbara A. Gage Prince George’s Community College Presented at the Middle Atlantic Regional Meeting of the American Chemical Society held at Princeton University, Princeton, NJ, 9-11 June 2003

NH 3 N 2 & H 2 A World of Symbolism N 2 (g) + 3H 2 (g)  2NH 3 (g) What is the difference between the contents of the two boxes? What happens if the substances in the first box react? What if one substance occurs in excess?

As chemists, we employ models Physical models – wooden ball & stick or the syringe Conceptual models – “molecules in the box” Mathematical models – Boyle’s Law or Beer’s Law P V PV = k

Beer’s Law – How do they grasp? Beer’s Law Simulator

N 2 (g) + O 2 (g)  2NO (g) What happens if you get this?

Microscopic – the particulate nature of matter Macroscopic - observations or results of an experiment Symbolic – mathematical equation or chemical equation The Three Realms of Chemistry The atomic level (abstract) How we represent itThe visible world or How we SEE it What is the mental model that our students have?

Building an understanding… Conceptual –static  dynamic Mathematical (using algebra) –discover relationships from data Connecting the realms –macroscopic, microscopic, symbolic …and following national standards!

The chemist’s toolbox… Graphing calculator/Excel – data handling, analysis, and modeling Chime – interactive molecular models in web- based activities Spartan – model building, animations Stella/Interactive Excel – mathematical simulations Netlogo/Java applets – particle/reaction simulations PowerPoint – animated discussion/elaboration and interactive tutorials

Support documents for students… Chime - HTML interactive online TI-83 Graphing Calculator – pdf file Excel – pdf file PowerPoint – pdf file Stella – for using simulations – pdf file Spartan – on organic lab manual CD

A journey into molecular geometry… Styrofoam balls and toothpicks Ball & stick models Chime molecules Lone pair distortion Molecular polarity Ideal geometries Construct and discover Ideal geometries

CH 4 CH 3 OH CH 3 SH Boiling Point Trends Molecular polarity activity

Advantages of Chime Freeware – plug-in for Internet Explorer or Netscape Use freestanding in web browser software or web pages Interactive – positioning and measurements (distances, angles) Multiple representations of molecules Electrostatic potentials maps - polarity Animations – reaction mechanisms or vibrations

The wooden ball and stick model Computer- generated model (Spartan 02) Compare and contrast the internal rotation of the O-O bond in di-t-butyl peroxide Dance of the Molecule

What does technology provide… Interactive and dynamic visualization Mathematical modeling and simulations Measurements – bond distances and angles Multiple representations Animations of vibrations Illustration of reaction mechanisms Examination of more complicated molecules Avoiding this mental model

The classroom… Becomes more learner-centered Models discovery learning and science process Involves investigative learning activities that strengthen problem solving skills through data-driven modeling and use of the WWW Promotes more discussion and elaboration and utilizes less lecture Provides more connections to biological molecules

Contact information Scott Sinex Barbara Gage College Pathways to the Science Education StandardsEducation Standards (NSTA, 2001)