Transcript Learning symmetry online – three

Inbal Tuvi-Arad
Department of Natural Sciences, and The Chais Research
Center for the Integration of Technology in Education, The
Open University of Israel
Learning with Visualizations
Symmetry Is All Around Us
 In life
 In Art
 In Chemistry
Introducing Symmetry
 Are these objects symmetric?
 How do we know that?
A Short Definition
 Symmetry is defined in terms of elements and
operations.
 Element – an axis, a plane, a point.
 Operation – rotation, reflection, inversion.
 An operation is symmetric if the resulting object is
identical to the original one.
How Do We Know?
 We rotate or reflect the object in our mind.
Rotation
Reflection
Molecular Symmetry
 Are these molecules symmetric?
 How can we help students visualize the symmetry?
OH HO
HO
H
O
H
H
water
H
H
C
H
methane
O
O
vitamin C
OH
Visualization Of Hidden Parts
 Present molecules in 3D
 Allow students to rotate structures on screen
 Present symmetry elements on screen
 Allow students to draw their own elements
Molecules Are 3D Objects
water
vitamin C
methane
Molecules Rotate In Space
water
methane
vitamin C
Molecular Symmetry Online
Molecular Symmetry Online
Symmetry Toolkit
http://telem.openu.ac.il/symmetry
Students’ Quotes
 “Before I couldn’t see anything. Now I do.”
 “I no longer need to imagine the structure in my
mind.”
 “I can see the symmetry element in my mind, but I’d
rather use the toolkit to draw it and check if I’m
right.”
Molecules Are Dynamic
 How much symmetry is lost due to vibration?
 How can we visualize it?
Continuous Symmetry
Perfect symmetry is rare:
 Molecules are dynamic entities
 Both physical conditions and chemical
environments creates structural distortions
 Minor substitutions creates major changes
in the symmetry of a molecule
Continuous Symmetry
 The Continuous Symmetry Measure determines the
distance of a given structure from perfect symmetry.
 It can be used to compare between various distorted
structures.
 Symmetry becomes a continuous property of matter.
Visualization Of Hidden Parts
 Present molecules in 3D
 Allow students to rotate the structure
 Calculate symmetry measures in the background
 Present original and resulting molecules interactively
CoSyM Website
http://telem.openu.ac.il/symmetry/csm
Typical Problem
 Is there an axis around
which we can rotate the
molecule by 180 and
obtain an identical
structure?
Ammonia
 If not, how would a
structure with
such an
Hypothetical
structure
axis
look
like? axis
with
180º
rotation
Teachers’ Quotes
 "When I teach about molecular structure I describe
only rigid structures, I never imagined how molecules
move."
 "I felt a big difference… the visualization opened my
eyes."
 "Now I am going to look at molecules in a different
way. There is no sharp distinction between symmetry
and no symmetry - there are a lot of levels in the
middle."
Summary
 Online Symmetry tools help students visualize the
hidden process of solving problems.
 Visualization of molecular symmetry, and continuous
symmetry contribute to deeper understanding of
molecular structure.
 Website tools can be used at various content levels
and for various teaching and learning purposes.
 Exposing teachers to advanced scientific content can
improve the way they teach more basic topics.
With Appreciation To:
 Colleagues:
 Dr. Paul Gorsky – The Open University of Israel
 Dr. Ron Blonder – The Weizmann Institute of Science
 Molecular Symmetry Online Team:
 Dov Garmise, Vered Tooby-Fishberg, Zeev Perl
 CoSyM website Team:
 Open University team: Dr. Dina Yogev-Einot, Dov Garmise,
Uri Shefi, Roy Sharoni, Itai Har-Even, Nadav Peer, Zeev
Perl
 Hebrew University team: Prof. David Avnir, Dr. Mark
Pinsky, Dr. Alexander Sterkin, Shadi Laham, Chaim Dryzon
Thank You!