Download Quantum Concepts for Chemistry

Prerequisites for Acquisition of
Quantum Concepts and Their
Comprehension by
Undergraduate Chemistry
Students
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
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The Boston University Team
Peter Garik (presenting)
Luciana Garbayo
School of Education
Alan Crosby, Dan Dill, Alexander Golger, and
Morton Z. Hoffman
Department of Chemistry
Peter Carr
Science and Mathematics Education Center
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
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Exploring Quantum Concepts in
Chemistry
This project is funded by the U.S
Department of Education’s Fund for the
Improvement of Post Secondary
Education (FIPSE).
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
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Project Objectives
The objectives of our FIPSE project are
• to find ways to introduce quantum
concepts into the chemistry curriculum;
• to design software that will support the
teaching of quantum concepts; and,
• to evaluate the success of our software
and curricular activities in supporting
student learning of quantum concepts.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
4
Why Quantum Concepts?
Why teach quantum concepts at an early
stage in the chemistry curriculum?
The epistemology of a mature science relies
upon foundational models for its research
program.
Such models provide a unifying perspective
on the physical world and support the best
insights and reasoning that we can
currently achieve.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
5
Why Quantum Concepts?
For cosmology, it is the inflationary theory of
the universe.
For geology, it is plate tectonics.
For biology, it is Darwinian evolution.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
6
Why Quantum Concepts?
For chemistry, one of the foundational models is
unarguably the quantum theory of atomic
structure and electronic behavior.
The pedagogical issue is where does it belong in
the curriculum?
Quantum concepts appear burdened with
additional abstractions (including mathematics)
that make them first appear forbidding to teach.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
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Why Quantum Concepts?
We argue that the unifying power of
quantum concepts is so great, and their
utilization for modern chemistry so
extensive, that finding ways to
successfully introduce them at an early
point in chemistry education is our
obligation to the students.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
8
Quantum Concepts in Chemistry
What are quantum concepts in chemistry?
The principal quantum topics in chemistry are:
1) The description of electrons and how they
behave in the presence of other charges. (This
includes atomic and molecular structure.)
2) The description of the interaction of radiation
with matter, and primarily with electrons.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
9
Quantum Concepts in Chemistry
Historically quantum concepts grew out of
analogies to electromagnetic theory. Since
the interaction of radiation with matter is a
key concept in chemistry (spectroscopy), it
is traditionally taught.
The properties of electromagnetic waves
provide an early access point for what we
refer to as “Quantum Readiness.”
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
10
Elements of Quantum Readiness
Quantum readiness includes understanding:
• What a wave is: time and space
dependence
• What an electromagnetic wave is:
– associated electric field
– associated magnetic field
•
•
The relationship between amplitude and
intensity
Constructive and destructive interference
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
11
Elements of Quantum Readiness
• How charged particles interact
• How a light wave interacts with a charged
particle
• What a quantum of energy is
Students prepared with these concepts
should have analogies for understanding
quantum phenomena.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
12
Quantum Concepts for Chemistry
What are the quantum concepts that we
would like students to master?
• The delocalization of the electron and its
description by a probability amplitude.
• The quantization of energy levels.
• The pairing of a wave function with an
energy.
• Constructive and destructive interference.
• The Pauli Exclusion Principle.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
13
Quantum Concepts in Chemistry
• The transition in energy levels associated
with absorption and emission of radiation.
•The geometry of atomic and molecular
orbitals.
• The atomic structure that arises from the
Aufbau Principle.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
14
Evaluating Students’ Conceptual
Understanding of Quantum
Concepts
As a first step to determining how students
learn quantum concepts, we engaged in a
qualitative research project.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
15
Theoretical Background and
Methodology
Chi and Slotta (1993) categorized entities as
matter (objects), processes, and mental
states.
For example, if a student thinks that a
photon is an “object”, then with it comes a
host of associations such as the photon
energy object collides with an electron and
knocks it to another orbital.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
16
Theoretical Background and
Methodology
We add to these categories the field
category in order to have a sensible set of
categories for quantum entities.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
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Design and Procedures
1) We interviewed students prior to, and
subsequent to, instruction on quantum
concepts.
2) Students were selected from a pool of
volunteers taking the honors general
chemistry course at a research
university.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
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Discussion
The students exhibited a series of
misconceptions, many of which match those
reported in the physics education literature.
Here we focus on students’ difficulty in
understanding the field nature of the
electromagnetic field and the field nature of
orbitals.
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
19
Pedagogical Strategy
We have designed software to provide students
with bridging analogies to understand the
properties of waves and fields.
The software modules have been authored in
Pedagogica™ as described in earlier talks. Over
the course of the next year we will be testing the
effectiveness of this software to assist students in
understanding the nature of electronic orbitals and
atomic structure.
(Go to Waves Module!)
Quantum Concepts in Chemistry
(http://quantumconcepts.bu.edu)
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