Presentation on theme: "Virtual and tactile molecular models: Their complimentary nature in Discovery-based general chemistry Scott A. Sinex and Barbara A. Gage Prince George’s."— Presentation transcript:
Virtual and tactile molecular models: Their complimentary nature in Discovery-based general chemistry Scott A. Sinex and Barbara A. Gage Prince George’s Community College Presented at the 228th American Chemical Society National Meeting in Philadelphia, PA on 22-26 August 2004.
the chemist’s world of multiple representations… C6H6C6H6
Are students still in flatland? Where are our students in this world?
the computer tools we use… ChemSketch – 2D chemical structure drawing (freeware) Chime/RasMol – molecular rendering (freeware) great for developing web- based activities Spartan – computational (expensive software) All available in open computer labs !
discovering confirming and verifying bond angles discovering molecular geometry…
discovering molecular polarity… H 2 0 H 2 S OF 2 SF 2 CH 2 0 SO 3 Use of electrostatic potential maps in Chime
discovering molecular distortions… Measure the bond angle (H-N-H) and explain any difference Measure and explain the non-ideal bond angles in each
discovering molecular flexibility… Are bond lengths and bond angle constant in a molecule? Can the nitro groups on ONC rotate around the C-N bond? ONC
discovering intramolecular interactions… With model in hand, ask students how the two chlorine atoms would like to be oriented?
uncovering molecular complexity… hemoglobin molecule Type of protein structure? How many helical chains? Hydrogen bonding
the tactile model... shows connectivity displays the real 3D in ideal state possibility of illustrating some intramolecular interactions (internal rotation) can test superposition of isomers can generate possible conformer structures by internal rotation
the tactile model… is rigid (set bond lengths and angles) true molecule size and shape not possible can fall apart! (at least some)
the virtual model… shows true arrangement plus distortions can change orientation and mode of display including complicated molecules allows measurements provides flexibility – animated vibrations can generate animated reaction mechanisms can display electrostatic potential maps A GREAT DISCOVERY TOOL!!!
the virtual model… may encounter incorrect structure files may not grasp the 3D nature on flat computer screen
tactile models virtual models Enhanced understanding of molecular structure in general chemistry and fosters a smooth transition into organic chemistry in the end…
For further information see our course webpages plus- Scott Sinex – http://academic.pgcc.edu/~ssinexhttp://academic.pgcc.edu/~ssinex Barbara Gage – http://academic.pgcc.edu/~bgagehttp://academic.pgcc.edu/~bgage CONFCHEM Fall 2004 – Teaching Computing in Chemistry Courses Paper #5: Empowering Student Learning with Molecular Visualization Tools in Discovery-based General ChemistryTeaching Computing in Chemistry CoursesEmpowering Student Learning with Molecular Visualization Tools in Discovery-based General Chemistry Thanks to MDL for Chime and ACD for ChemSketch!!!