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Misconceptionsin Chemistry

Frank Jenkins and David Geelan

University of Alberta

Chemistry Education Workshop

May 2003fjenkins@ualberta.net and david.geelan@ualberta.ca

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Epistemological Theory

• Epistemology is the branch of philosophy that deals with theories about knowledge (what we know, how we know, how we test knowledge claims).

• Constructivism is often presented as a theory about teaching (pedagogical theory), but it is actually a theory about knowledge.

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Constructivism

• The basic idea of constructivism is that learners are not ‘blank slates’ or ‘empty cups’ to be filled with knowledge, but that they already have a huge body of knowledge and life experience. Because knowledge is a structured network rather than a disconnected ‘heap’ of facts, new knowledge is built on the foundations of existing knowledge and integrated with it.

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Constructivism II

• This suggests the idea that knowledge cannot be directly transmitted from one person to another. The knowledge must be broken down into some form of information (speech, text, drama, art), which is then construed (i.e. viewed through the construction system of) the learner, and new knowledge (not necessarily the same) is then constructed within the learner.

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Kinds of Constructivism

• Personal constructivism—Jean Piaget

• Constructivist psychology—George Kelly

• Radical constructivism—Ernst von Glaserfeld

• Social constructivism—Joan Solomon, Frederick Steier, and Kenneth Gergen

• Socio-cultural constructivism—Lev Vygotsky

• ZPD (assisted) constructivism—Lev Vygotsky

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Implications for Learning

• Students should be actively engaged in their learning, rather than passively receiving.

• Learning should begin from ‘where students are’ in their knowledge.

• Science students need opportunities to test their knowledge frameworks against other knowledge and against the physical world.

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Implications for Teaching

• It is important for teachers to understand, as far as possible, their students’ ‘prior knowledge’ – what the students already bring to class in their minds. In this context, knowledge should be understood as a rich, complex network, rather than as a simple list of ‘school facts’ already learned.

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Another Early Constructivist?

“Be very, very careful what you put into that head, because you will never, ever get it out.”

Thomas Cardinal Wolsey (1471-1530)

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Summary

• The key implication of constructivist theory is that teaching, even good teaching, doesn’t necessarily imply learning.

• Teachers need to attend explicitly to their student’s prior knowledge and the processes of assimilation and accommodation that occur in constructing new knowledge,

• Teachers need to provide opportunities for students to actively engage with and test their new knowledge frameworks.

2003-05-05 Keith Taber, V1, p5 12

Alternative Conceptions

• biology—the mass of the tree comes from nutrient in the soil

• physics—a continuously/continuing applied force results in a maximum speed

• chemistry—attractive force by the nucleus is shared among the electrons

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Aristotelian Concepts

Many concepts held by students are common sense (logical) conceptions held by Aristotle—not bad company.

• heavy objects fall faster than light objects• all materials are made of a combination of

earth, air, fire and water• for every property there is an opposite

property; e.g., hot-cold and dry-wet

2003-05-05 Keith Taber, V1, p1 14

Alternative Conceptions

• Water turns blue when copper(II) sulfate is added “because the copper sulfate has a chemical inside it that turned the water blue.”

• A compound is “a substance that contains 2 or more of the same kind of atom.”

• Hydrogen reacts with fluorine “because fluorine wants to gain an electron and hydrogen wants to lose one.”

2003-05-05 Keith Taber, V1, p6 15

Alternative ChemistryResearch indicates these alternative concepts:• neutralization always results in a neutral product

– shows the importance of language in learning science

• neutrons neutralize the charge of protons– this explains how protons exist together in nucleus

• isomers are always members of the same class– a wrong level of generalization (to within the class)

• a hydrogen bond is a covalent bond to hydrogen– shows an error in categorization

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Why? Alternate Conceptions

• Students may not be paying attention.– But teachers usually notice this.

• Students may not have understood.– But teachers usually check for understanding.

• Students may have forgotten.– But teachers usually review and reinforce.

So why? There must be another answer.

2003-05-05 Keith Taber, V1, p1, quoting Rosalind Driver

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Rules of Evidence Ignored?

Students are typically unacceptable scientists.

• unable to see refutation or falsification

• see what they expected to see

• fail to record results accurately (accurately in the sense of seeing and recording)

Students see with their brain, not with their eyes.

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Oops!

“It is the concept which decides what we can observe.”

Albert Einstein

Was Albert Einstein the first constructivist?

Are students really so different than scientists?

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A Useful Distinction

• alternative conception—refers to a single concept held by the student– e.g., Arhennius concept of acids

• alternative framework—refers to a complex or structure of related ideas– e.g., a concept map that connects the Arhennius

concept of acids to related chemistry concepts

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Alternative Framework

An alternative framework for bonding:

• reactions occur between atoms (only)

• all reactions occur to obtain a stable octet

• only two kinds of bonds—ionic and covalent (all other bonds are subcategories)– ionic bonding is due to the transfer of electrons– hydrogen bonding is covalent bonding

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Atoms are taken too seriously!by students and teachers

(Mis)Conceptions about atoms:• reactants always start off as atoms• sodium chloride is made of atoms (molecules)• bonding in NaCl(s) is explained as the transfer of

electrons between atoms• atoms retain their identity in molecules and get

back their same electrons on decomposition• atoms are unstable (spontaneously ionize)• want (anthropomorphically) to lose or gain electrons

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Keith Taber’s Advice

• Students are likely to hold a wide range of alternative ideas.

• Not all of the alternative ideas are highly significant.

• Some of the alternative ideas are highly significant.

Therefore, take learners’ ideas seriously.

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Concepts are context sensitive.

• Concepts, like “work” and “theory”, are context sensitive. We switch back and forth easily.

• Everyday language and scientific language may conflict and result in alternative conceptions.

• Everyday knowledge may be stored separately from academic knowledge—or not.

• Physics and biology knowledge may be stored separately from chemistry knowledge—or not.

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Possible Outcomes

1. New ideas supplants old idea

2. New ideas treated as unrelated to old idea

3. New (unrelated) idea is forgotten easily.

4. New idea is not understood—unrelated to the students’ existing ideas.

5. New idea is related to the old idea in an incorrect manner—an illogical connection.

2003-05-05 Keith Taber, V1, p155 26

Constructing Knowledge (K)

1. we construct K from our experiences

2. we construct on a limited mental scratch-pad

3. we reconstruct K into manageable chunks

4. we reconstruct K into useful K

5. we make sense in terms of what we know

6. we create meaning based upon prior K

7. we construct on a foundation of prior K

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Keith Taber’s books provide:

• research uncovering alternative conceptions

• probes to identify alternative conceptions

• exercises for challenging (mis)conceptions

• teaching strategies to avoid misconceptions

• ideas for helping students acquire appropriate scientific conceptions

• activities to help students help themselves

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Keith Taber’s book availability

Chemical misconception—prevention, diagnosis and cure © 2002 (combo is 61 $)

• Volume I: theoretical background (44 $)

• Volume II: classroom resources (28 $)

• Printed by the Royal Society of Chemistry• http://www.rsc.org ISBN: [combo] 0-85404-390-X

• ISBN: V1: 0-85404-386-1 & V2: 0-85404-381-0