College chemistry students' understanding of potential energy in the context of atomic-molecular interactions

JOURNAL OF RESEARCH IN SCIENCE TEACHING

CollegeChemistryStudents’Understanding ofPotentialEnergy in theContext ofAtomic–Molecular Interactions

Nicole M. Becker and Melanie M. Cooper

Michigan State University, 578 S Shaw Lane, East Lansing, Michigan 48823

Received 24 January 2014; Accepted 8 June 2014

Abstract: Understanding the energy changes that occur as atoms and molecules interact forms the

foundation for understanding the macroscopic energy changes that accompany chemical processes. In order

to identify ways to scaffold students’ understanding of the connections between atomic–molecular and

macroscopic energy perspectives, we conducted a qualitative study of students’ conceptualization of

potential energy at the atomic–molecular level.We used semi-structured interviews and open-ended surveys

to explore how students understand potential energy and use the idea of potential energy to explain atomic–

molecular interactions in simple systems. Findings suggest that undergraduate chemistry students may rely

on intuitive interpretations of potential energy, incorrect interpretations of curricular definitions (including

the idea that potential energy represents stored energy) andheuristics rather than foundational understandings

of the relationships between atomic–molecular structure, electrostatic forces and energy. Thus, we suggest

that more explicit attention to the nature and role of potential energy in the undergraduate chemistry

curriculummaybe needed. # 2014 Wiley Periodicals, Inc. J Res Sci Teach

Keywords: chemistry; misconceptions; conceptual change

Energy represents a core idea across scientific disciplines and is central to understanding the

behavior of chemical systems. From interactions between atoms and molecules to the networked

reactions of biological systems, understanding the role of energy is key to understanding these

systems. As such, the recent Framework for Science Education highlights the role of energy as

both a core idea and a crosscutting concept that extends throughout numerous STEM disciplines

(National Research Council, 2012). The Framework suggests that by emphasizing relationships

between accounts of energy transfer and transformation across different scales and disciplinary

contexts instructors may be able to help students develop more coherent frameworks for

reasoning about energy-related phenomena.

However, there is considerable evidence that few students develop such a coherent

understanding as the result of participation in undergraduate-level chemistry courses (Bain,

Moon, Mack, & Towns, 2014; Goedhart & Kaper, 2003; Sreenivasulu & Subramaniam, 2012;

Taber, 2003). For instance, students’ understanding of the energy changes that accompany

bonding and interactions between chemical species are, at best, inconsistent (Barker &

Millar, 2000; Boo, 1998; Ebenezer & Fraser, 2001; Galley, 2004; Nahum, Mamloka Naaman,

Hofstein, & Krajcik, 2007; Teichert & Stacy, 2002). Teichert and Stacy (2002) reported that

undergraduate students may believe energy is released both on bond formation and on bond

Contract grant sponsor:NSFDUEAwards;Contract grant numbers: 0816692; 1122472.

Correspondence to:N.M.Becker; E-mail: [email protected], [email protected]

DOI10.1002/tea.21159

Publishedonline inWileyOnlineLibrary (wileyonlinelibrary.com).

# 2014 Wiley Periodicals, Inc.

breaking, suggesting that they hold discordant and inconsistent views about how energy changes

as bonds are formed. Especially problematic is the observation that studentsmay believe that bond

breaking releases energy, despite the fact that bond breaking is an endothermic process (Barker &

Millar, 2000; Boo, 1998; Galley, 2004; Storey, 1992; Teichert & Stacy, 2002). Even after

instruction, around 50% of undergraduate students still hold this belief (Barker & Millar, 2000;

Boo, 1998).

Similarly, energy topics ranging from ionization energy to enthalpy have also been shown to

be challenging for students. When reasoning about ionization energy, students may struggle to

apply basic principles of electrostatics and may explain ionization energy trends using, for

example, the octet rule or ideas about stability rather than a foundational understanding of the

relationship between energy and atomic–molecular structure (Taber, 2003). Similarly, in

thermodynamics contexts, Nilsson and Niedderer (2014) observed that students may attribute

work to atomic–molecular phenomena such as the conversion of potential to kinetic energy rather

thanmacroscopic changes in pressure and volume, suggesting a disconnect betweenmacroscopic

ideas such as heat and work to their understandings of molecular-level processes. Lacking a

coherent framework for reasoning about energy in chemical systems, even advanced studentswho

are otherwise successful in using mathematical resources may struggle to understand what those

representations mean in terms of fundamental energy concepts and the atomic–molecular scale

(Hadfield & Wieman, 2010). Given that understanding energy changes at the atomic–molecular

level forms the foundation for understanding the macroscopic energy changes that accompany

chemical processes, these observations are troubling (Cooper,Klymkowsky,&Becker, 2014).

A Re-Evaluation of the Role of Energy at the Atomic–Molecular Level

One recommendation for improving students’ understanding of energy concepts has been

made by the recent Framework for Science Education (National Research Council, 2012), which

advises simplifying energy instruction to focus on a smaller number of core energy concepts that

can be applied across both atomic–molecular andmacroscopic contexts.As the Framework notes,

The idea that there are different forms of energy, such as thermal energy,mechanical energy,

and chemical energy, ismisleading, as it implies that the nature of the energy in each of these

manifestations is distinct when in fact they all are ultimately, at the atomic scale, some

mixture of kinetic energy, stored energy, and radiation (National Research Council, 2012,

p. 122).

At the heart of the Framework’s approach to energy instruction is an electrostatic model of

atomic–molecular interaction in which energy changes are modeled both as motion of particles

(kinetic energy) and “stored energy,” representing energy stored in the electrical, magnetic, or

gravitational fields that mediate interactions between particles (National Research Council,

p. 121). The Next Generation Science Standards (Achieve, 2013), which uses the Framework as a

guide for establishing what students should learn and the sequence in which they should learn it at

the K-12 level, reflect this emphasis on the ideas of “stored” energy (also called potential energy)

and kinetic energy as tools to predict and explain energy phenomena across atomic–molecular and

macroscopic scales.

A crosscutting concept closely tied to the idea of potential energy in chemical systems is the

cause and effect relationship between forces and change in energy. The Framework suggests that

by grade 12 students should recognize that electrostatic forces between atoms andmolecules arise

from the subatomic structure of atoms. Students should also identify that these electrostatic forces

are the mechanism by which atoms and molecules interact and by which energy is stored or

Journal of Research in Science Teaching

2 BECKER AND COOPER

transferred between particles. Mathematical expressions may be used to quantify how the

electrical force or stored energy of a system depends on the charges of particles and their relative

positions. For instance, electrostatic interactions between particles are commonly modeled by

Coulomb’s law, Fak ¼ q1q2r2 , where q1 and q2 represent the charges of the interacting particles and

r represents the distance between them (or in the case of London dispersion forces may be

proportional to 1/r6).

A second crosscutting concept closely linked to the idea of potential energy in chemical

systems is the idea that systems evolve towards more stable states that minimize the amount of

energy stored in magnetic or electrical fields. In atomic–molecular contexts, stability and the

minimization of potential energy determine equilibrium distances for interactions between atoms

andmolecules.

The aim of this approach is to have students recognize thatmacroscopic energy changes, such

as heat energy released by an exothermic chemical reaction, originate in energy changes that occur

as atoms andmolecules interact. Ideally this approach provides students with a coherent approach

to energy ideas that cuts across disciplines and allows students to make connections between

treatments of energy that have historically been quite disparate.

The Role of Potential Energy in Undergraduate General Chemistry

Although the Framework is designed to address learning at the K-12 level, it is our contention

that the approach to energy instruction outlined by Framework may provide an opportunity to

present more a connected account of energy in undergraduate introductory chemistry courses

as well. We find that electrostatic models of atomic–molecular interaction and corresponding

models of energy as potential and kinetic energy are among several models that are commonly

introduced in undergraduate chemistry contexts (e.g., see Bruice, 2010; Tro, 2012). The

electrostatic model of interaction plays a prominent role in the curricula as it may be used to

explain a wide array of concepts, ranging from the energy changes that accompany covalent

bonding to emergent properties ofmacroscopic systems such asmelting and boiling points.

In order to reason about energy changes in more complex atomic–molecular systems

typically encountered at the undergraduate level, students must refine their understanding of

atomic–molecular structure and connect it to their understanding of electrical interactions

between species. For instance, to understand energy changes that accompany interactions between

neutral atoms (such as helium), studentsmust identify that randomfluctuations in electron density

give rise to temporary dipoles, which in turn contribute to induced dipole interactions between

adjacent species. To understand the energy changes that accompany interactions between species

such as water or ethanol, an understanding of valence shell electron pair repulsion (VSEPR)

theory and understanding of additional concepts such as electronegativitymaybe necessary.

At the undergraduate level, graphical models that more closely approximate the contribution

of attractive and repulsive interactions to the potential energy of the system may also be

introduced. For example, theMorse potential (Figure 1) may be used tomodel potential energy as

a function of inter-nuclear distance for a system of two interacting hydrogen atoms. To interpret

models such as this, students must that recognize that the potential “well” (or minimum) in

Figure 1 corresponds to a state at which the system is said to be “stable.” They must also identify

that stable interactions are formed when there is a balance between these attractive and repulsive

forces (Nahumet al., 2007).

While bonding phenomena are most often approached from an electrostatics perspective at

the K-12 level, undergraduate chemistry students will also be exposed to alternate models of the

energy changes associated with bonding such as valence bond theory or molecular orbital theory,

both of which draw from quantum-mechanical models of atomic structure and interaction.


COLLEGE CHEMISTRY STUDENTS OF POTENTIAL ENERGY 3

Additionally, energy phenomena may be approached from a thermodynamics perspective in

whichmathematicalmodels are used to track energy flux into and out of a defined system.As such,

undergraduate chemistry students must not only be able to relate atomic–molecular perspective

on energy change tomacroscopic phenomena, theymust also develop the capacity to compare and

contrastmultiplemodels of the energy changes in chemical systems.

There is certainly evidence from related disciplines, including biology and physics contexts,

which suggests that developing an understanding of potential energy or “stored” energy may be

challenging for students. In physics contexts, it has been demonstrated that students may consider

gravitational potential energy to be a property of a single object rather than a system of interacting

objects (Jewett, 2008; Lindsey, Heron, & Shaffer, 2012). Students may also interpret the potential

energy quite literally as the “potential” or capability for an object to move or cause change

(Loverude, 2005), an idea that may hinder their ability to extend the idea of potential energy to

newcontexts such as atomic–molecular interactions. In biology contexts, it has been noted that the

way bond energies are treated in biological systems tends to reinforce the idea that bonds store

energy and release energy when those bonds are broken, rather than when new bonds are formed

(Cooper&Klymkowsky, 2013; Storey, 1992).

Even if students entered general chemistry courses with a solid foundation for understanding

potential energy in macroscopic contexts, for instance in gravitational systems, translating those

understandings to the atomic–molecular level may be challenging. While students may

reasonably be expected to infer that potential energy at the atomic–molecular level pertains to

systems of interacting objects based on their positions in the sameway that gravitational potential

energy does, there are several key differences between potential energy in gravitational and

electrical contexts that may escape students’ notice. First, the nature of the relevant force in each

context is distinct: the gravitational at the macroscopic scale, versus predominantly electrostatic

at the atomic–molecular. While gravitational potential is always attractive, meaning that the

potential energy stored in the system will decrease as the objects move closer together,

electrostatic interactions may involve interactions between positive or negatively charged objects

Figure 1. Potential energy curve for hydrogen atom interactions.


4 BECKER AND COOPER

and thus the electrostatic potential energy may increase or decrease as the objects move closer

together. When left to their own devices to compare their understanding of potential energy in

macroscopic systems (gravitational potential energy) with potential energy in atomic–molecular

systems (electrical potential energy), these differencesmay be difficult to appreciate.

While a robust understanding of energetics at the atomic–molecular scale may well support

the development of a coherent framework for discussing energy in chemical systems little

research from chemistry contexts exists to support this idea. The qualitative study presented here

aims to address this gap in the literature by describing students’ understandings of potential energy

in atomic–molecular systems. This work will serve as a foundation for further exploration of how

undergraduate students connect their understanding of atomic–molecular energy transformations

tomacroscopic perspectives on energy.

Methods

The goal of this study was to investigate how students understand the concept of potential

energy in the context of interactions between atoms and molecules. If chemistry instructors are to

help students connect their understanding of potential energy in atomic–molecular systems to

macroscopic energy, we must better understand how students reason about potential energy in

the first place and what prior knowledge they bring to chemistry contexts (Novak, 2002;

Vygotsky, 1978). To this end, we conducted a qualitative study in order to explore the following

research questions:

• Howdo students understand the concept of potential energy in general, and at the atomic–

molecular level?

• How do students conceptualize potential energy in the context of atomic–molecular

interactions?

Participants for this research study were recruited from undergraduate chemistry courses at

a medium-sized Southeastern research university. Participants ranged from first-year science

students enrolled in general chemistry to upper-division chemistry majors. All students pursued

majors in science or health science fields and were enrolled in chemistry as part of the

requirements for their degree programs. Students were notified of their rights as research

participants and provided informed consent prior to participation in the study.

Online Open-Ended Survey

In order to explore our first research question, we developed an open-ended survey that asked

students to describe their understanding of kinetic and potential energy in general and at the

atomic–molecular level. Questions related to potential energy included:

• What do you think potential energy is? Please provide an example to illustrate your

thinking.

• At the atomic–molecular level, what do you think potential energy is? Please give an

example to illustrate your thinking.

Students enrolled in three chemistry courses completed the survey online as part of the

homework requirements for their courses (Table 1).All courseswere taught using apredominantly

lecture format, with periodic “clicker” questions and small group activities during class time. The

second authorwas the instructor for the organic chemistry course. Of the 142 participants enrolled

in Fall 2012 cohort of the general chemistry 1 (GC1) class, 61 of these students were also enrolled



in the Spring 2013 semester of general chemistry 2 (GC2) (taught by same instructor as the GC1

course).

In each of these three courses, the beSocratic online platform1 was used for homework tasks

(Bryfczynski, 2012; Byrfczynski et al., 2012). Homework tasks were graded for completion. In

the majority of homework tasks, students received feedback on the appropriateness of their

responses through the pre-established conditions in the beSocratic program that were set by the

instructor. Students were allowed to revise their responses based on the feedback. Homework

tasks in each of the three courses were used as contexts for in-class discussion as the instructors

routinely selected samples of student work for in-class review. However, students received no

feedback on their responses to the surveyused to gather the data for this study.

Semi-Structured Interviews

To examine students’ understanding of potential energy in atomic–molecular systems with

greater depth, we developed a semi-structured interview protocol in order to elicit students’

understandings of the energy changes that accompany atomic–molecular interactions in simple

systems. As contexts for the discussion, students were asked to consider interactions and energy

changes that might occur in simple atomic–molecular systems, for instance as two helium atoms

or two water molecules interact (full interview protocol in the Supporting Information). The

interview protocol was piloted with five advanced undergraduate and graduate students and was

refined for clarity prior to the full study.

Participants for the full study were recruited on a voluntary basis from the GC1 course

during the last month of the Fall 2012 semester. Interviews were conducted by a post-doctoral

researcher (first author) who was not involved in the instruction of any of the courses and

a graduate student who was a teaching assistant for the GC1 course. Participants were not

identified to the course instructor and no incentives were offered to interview participants. The

graduate student researcher was not present when interviewing students enrolled in her teaching

sections.

Our initial analysis of the survey data from GC1 and OC suggested that many students

struggled to use the idea of potential energy productively in atomic–molecular contexts. Thus we

opted to expand our participant pool to include students from advanced chemistry courses in order

to better represent the ways in which students’ ideas about atomic–molecular level energetics

might evolve as they develop expertise. Table 2 summarizes the number of participants and the

courses in which they were enrolled. Participants designated as “upper division” (UD) were

enrolled in advanced undergraduate chemistry courses other than organic chemistry (for example,

physical chemistry, inorganic chemistry, etc.).

Interviews lasted between 15 and 45minutes in length. Audio and written works generated

during the interviews were recorded using a Livescribe pen (http://www.livescribe.com/en-us/)

and copies of student written work were collected at the completion of each interview. The

research team transcribed the interviews verbatim.

Table 1

Participants for online written questionnaire

Course Number of Participants

General chemistry I, GC1 (Fall 2012) 142General chemistry II, GC2 (Spring 2013) 188Organic chemistry I, OC (Fall 2012) 102Total 333


6 BECKER AND COOPER

http://www.livescribe.com/en-us/

Data Analysis

Data were analyzed using an inductive approach informed by the constant comparative

method (Corbin & Strauss, 2008). We began our analysis by open coding student responses to the

online survey with the aim of identifying trends in student reasoning. A preliminary set of codes

was developed using the online survey dataset andwas refined upon analysis of the interview data.

Data fromboth the survey and interviewswere combined for the final iteration of analysis and both

datasetswere analyzed using the same set of codes.

In order to determine coding reliability for our analysis, two researchers independently

coded a portion of the online survey responses (�20% of responses for two different questions).

Inter-rater reliability was evaluated using the Cohen’s kappa statistic, which indicated a high level

of agreement between the two raters (Cohen’sKappa� 0.84with p< 0.001).

Findings

Across all groups of participants, we observed that many students struggled to appropriately

connect their understanding of potential energy at the atomic–molecular scale to their

understanding of atomic–molecular structure and electrostatic forces between atoms and

molecules. We observed three trends in students’ conceptualization of potential energy that we

believe contributed to student difficulties in reasoning about potential energy changes in atomic–

molecular systems. First, we observed that students frequently conceptualized potential energy as

the capability of atomic–molecular species to interact, react, or undergo change.While in a certain

sense, potential energy can be considered related to a capacity for motion or change, the idea that

potential energy represents an ability to form a bondwas of little use in explaining energy changes

that accompany interactions that did not obviously involve covalent bonding. Second, we

observed that some students considered potential energy to energy “stored” in interactions

between atoms andmolecules, though few could explain under what circumstances energy would

be stored by a system. Third, we observed that students commonly associated potential energy

with the stability of a system, though most often without a clear sense of whether stability was a

cause or effect of a change in energy.

While in some contexts interpretations of potential energy as capability, stored energy, and

stability are not necessarily incorrect, without a concomitant understanding of the role of

electrostatic force and relative position of particles in determining the potential energy of a system

these ideas often seemed to inhibit more productive attempts at reasoning about the energy

changes at the atomic–molecular scale.

Potential Energy as Capability

The most prevalent conceptualization of potential energy in chemical systems was the idea

that potential energy represents a literal “potential” or capability for motion or change. At the

Table 2

Interview participants

Course Number of Participants

General chemistry I (GC1) 8General chemistry II (GC2) 1Organic chemistry I (OC) 9Upper division (UD) 4Total interview participants 22



atomic–molecular level, participants used the idea of potential energy as capabilitywith a range of

interpretations, from the idea that potential energy represents an ability of an atom or molecule to

move, interact, or react. Most common was the idea that potential energy represents the ability of

an atom ormolecule tomove or change configuration. For instance, one general chemistry student

commented that he understood potential energy as the “ability of the atom or sub-atomic particle

to be moved/borrowed between atoms” (GC1, survey). Similarly, an organic chemistry student

commented that she viewed potential energy as “the potential to undergo a change in structure or

configuration.” (OC, survey).

Other participants interpreted potential energy as related to a system’s ability to react or

interact. For instance, a participant in the second semester general chemistry course described

potential energy as “the potential for molecules to interact” and illustrated her thinking with the

following example: “If two molecules are across the room from each other, they will have a low

potential energy. However, as they move towards each other the potential energy increases for

them to react” (GC2, survey). According to her interpretation of potential energy as related to the

likelihood of reacting, this student predicted that potential energy would increase as the two

molecules approach.While she indicated the atomswould react in someway, she did not elaborate

on how she believed the atoms would interact. Thus it is unclear as to whether or not she

understood potential energy to be related to electrical interactions between particles. Assuming

that the particles might interact in a favorable way, her prediction that potential energy would

increase as atoms approach towards a distance atwhich theywould “react”would be incorrect.

Example of Student Reasoning About Potential Energy as Capability From Interviews

Similarly, in the semi-structured interviews we observed that the idea of potential energy as

the ability to react or bond was seldom a useful tool for predicting and explaining energy changes

as atoms and molecules interact. To illustrate this trend consider Paul, an organic chemistry

studentwho expressed a belief that potential energy represents an atom’s ability to form a covalent

bond. When prompted to discuss his understanding of how two hydrogen atoms might interact,

Paul commented that he believed the two hydrogen atoms would approach and form a covalent

bond, which he described as the formation of a molecule by the sharing of electrons. When asked

to describe how that interaction might affect the energy of the system, Paul concluded (correctly)

that forming a bond would result in a decrease in the potential energy of the system. He explained

his reasoning as follows.

Paul:Well, they have greater potential energy when they’re further apart than when they’re

closer together because they have greater potential to make an atom when they’re closer

together, um a molecule. The farther apart they get the less likely they’re going to form a

molecule so that kinda affects the potential energy.

Paul’s prediction that potential energy would decrease as the atoms approach seemed based

on his understanding of the probability of forming a bond at different distances; he viewed atoms

that were closer to one another asmore likely to form a bond than those that were further apart. He

also seemed to associate lower potential energywith a greater likelihood of forming a bond.

A more complete account of bonding and its influence on the potential energy of the system

would also address the role of electrical forces between hydrogen atoms. The systemof interacting

hydrogen atoms can be considered to store potential energy based on the relative positions of the

atoms and the uneven charge distributions imparted by their fluctuating electron densities.

Potential energywouldminimized at the bond length because of the fact that attractive interactions

and repulsive forces between the species are balanced at the bond length distance.


8 BECKER AND COOPER

While Paul correctly predicted that potential energy would be lowered by the formation of a

covalent bond between two hydrogen atoms, his framing of potential energy as an ability to form a

bond became problematic as he considered other systems of atoms andmolecules. For instance, as

he reasoned about how two helium atomswould interact, he recalled that in contrast with a system

of hydrogen atoms, helium atomswould be unlikely to form a covalent bond.Based on his framing

of potential energy as the ability to form a covalent bond, he concluded that no change in either

potential or kinetic energywould occur as the heliumatoms interact.

Paul: They’re extremely unlikely to make any sort of attempt at making a bond so they’re

not going to need to change energy frompotential to kinetic.

In fact, helium atoms may interact via London dispersion interactions, electrical interactions

caused by momentary fluctuations in electron distribution around a neutral atom. Though weaker

than covalent bonds (in part because of the distance over which they act) these interactions result

in a similar change in the potential energy of the system: potential energy is minimized at the

distances at which the interaction is most stable. Later in his interview, Paul listed London

dispersion forces as a type of interaction that could be formed by helium atoms, suggesting

familiaritywith this type of interaction. However, when asked to elaborate on his understanding of

London dispersion forces, hewas unable to provide a description in terms of atomic structure and

its relationship to electrostatic interactions.

Paul’s incorrect conclusion that interactions between helium atoms would not change the

potential energy of the systemmay in part stem fromhis framing of potential energy as exclusively

related to covalent bonding. The tendency of students to view covalent and ionic bonding as

distinct from intermolecular interactions, despite the fact that all arise from similar types of

electrostatic interactions, has been noted as a persistent difficulty and one that may be encouraged

by traditional approaches to instruction (Kronik, Levy Nahum, Mamlok-Naaman, & Hofstein,

2008; Nahum et al., 2007; Taber, 2003). Our own experience suggests that while traditional

general chemistry texts may discuss potential energy changes in conjunction with formation of

covalent bonds, explicit discussions of atomic structure and their relationship to forces and

potential energy in the context of intermolecular interaction are far less common. Prior to his

interview, Paul may have never been explicitly asked to think about how potential energy would

change as two helium atoms interact. Thus it is not surprising that he struggled to reconcile his

understanding of energy changes that accompany covalent bonding with energy changes that

accompany intermolecular interactions.

Potential Energy as Stored Energy

The second most prevalent conceptualization of potential energy in chemical systems

was the idea that potential energy represents “stored” energy. According to an electrostatic

model of particle interaction, potential energy is “stored” by the system based on the relative

positions of interacting particles. To an expert, an interpretation of potential energy as stored

energy is meaningful only with a concurrent understanding of the factors that influence energy

storage in a particular context, namely the forces that determine the interaction between

species and their relative positions. Our participants’ interpretations of stored energy varied

considerably, ranging from relatively robust discussions which referenced the ways in which the

potential energy of a system depends on the charge distributions and the relative positions of

interacting particles to less sophisticated interpretations in which potential energywas viewed as

stored within an atom or bond but without a concurrent discussion of charge and position of

particles.



As an example of a more sophisticated interpretation of potential energy at the atomic–

molecular level, one organic chemistry student highlighted the role of position of interacting

objects, describing potential energy as “the stored energy a molecule has due to the position of its

substituents, bond lengths, bond angles etc.” (OC, survey). Another student emphasized the role

of forces between particles, noting that potential energy relates to “energy stored from repulsions

between atoms” (OC, survey). For the majority of students, the exact nature of forces acting at the

atomic–molecular scalewas largely implicit. Rather than discussing electrostatic forcesmediated

by electric fields, students discussed attractive or repulsive interactions. This is not surprising

given that this is nearly always how students are taught to reason about interactions at the atomic–

molecular level.

Relatively sophisticated interpretations of potential energy such as thesewere in theminority

and students held a range of alternative interpretations. For instance, some participants described

potential energy as related to the extent to which a particle is in motion. A general chemistry

student, for instance, commented that she believed that “an atom has stored energy before it is

moving” (GC1, survey). Another explained that he believed atoms had potential energy “when

atoms are sitting still, like the atoms of a solid” (GC1, survey). This idea may stem in part from

macroscopic observations related to kinetic and potential energy. For instance, a stationary object

such as a ball may be said to have potential energy based on its position relative to the earth. If

released from a position above the ground, the potential energy of the ball may be transformed to

kinetic energy, which is readily observed as motion. However, at the atomic–molecular level, the

idea that potential energy represents the energy of a stationary particle is troublesome as atoms

and molecules are in constant motion. This idea was most prevalent among general chemistry

students and considerably less prevalent in the organic chemistry responses (12.7% in GC1,

10.1% inGC2, 3% inOC).

Some students considered stored energy to be a property of an individual object such as an

atom or subatomic particle. For instance, a first-semester general chemistry student described

potential energy as “the amount of energy the atom can have, such as how much energy the

protons, electrons, and neutrons hold,” (GC1, survey). Students in second-semester general

chemistry more often attributed potential energy to bonds or interactions between molecules

(Figure 2). This observation may indicate a potentially positive shift towards localizing relevant

energy interactions between atoms and molecules (rather than at the nuclear level). However,

students who indicated that energy could be stored by bonds often did sowith the assumption that

energy was stored could be released if the bond were broken. As one student described their

understanding, “Potential energy at the molecular level would be the energy that is in bonds. This

energy is stored and can be released” (GC2, survey). In fact, the opposite is true and breaking both

covalent bonds and intermolecular interactions requires an input of energy (Boo, 1998; Teichert&

Stacy, 2002). This idea was also fairly prevalent in the semi-structured interviews. Of the 22

interview participants, 6 participants from organic chemistry and upper division courses indicated

a belief that energy could be stored by bonds and releasedwhen bondswere broken.

While there is truth to the idea that energy is “stored” by interactions of atoms andmolecules,

it is important to qualify that a system of atoms in a bond “store” less energy in their interaction

than the two un-bonded atoms and thus energy would be required to separate the atoms in a bond.

The colloquial use of the term “stored” seemed to impede some students from making this

interpretation.

Example of Student Reasoning About “Stored” Energy From Interviews

To illustrate the way in which students’ conceptualization of potential energy as “stored

energy” contributed to students’ reasoning about energy changes in atomic–molecular systems,


10 BECKER AND COOPER

consider Kenneth, an upper-division student enrolled in a physical chemistry course. While

Kenneth was able to correctly predict changes in potential and kinetic energy in simple atomic–

molecular systems, his interpretation of potential energy as stored energymade it difficult for him

to connect accounts of potential energy change across different atomic–molecular contexts.

In all three atomic–molecular systems (interaction of helium atoms, hydrogen atoms, and

water molecules) Kenneth demonstrated an ability to appropriately coordinate his understanding

of atomic–molecular structure, electrical forces and energy changes. For example, when asked to

describe his understanding of how two helium atoms would interact he described each helium

atom as having fluctuating electron density around a positively charged nucleus. He identified that

the atoms could interact viaLondon dispersion interactions and that interactions between particles

could be either attractive or repulsive depending on the distance between the atoms. When asked

to describe his understandingof how the energyof the systemmight change as the atoms approach,

Kenneth drewonhis understanding of the electromagnetic interaction between the particles.

Kenneth: Well, these [helium atoms] as they’re pretty far apart then, the potential energy

between them is pretty low because they’re very weakly interacting inert gas molecule-

s. . .the electrical energy between them, is probably not very strong, there’s not a strong

electric field, youknow, potential between the two if they’re far apart.

Interviewer:Ok. Sowhat if they startmoving closer together?

Kenneth: If they start moving closer together then, their electron clouds are going to start

interacting and repelling each other. If they get close enough then they are, the protons will

be attracted to the, um, electrons, but only, uh fleetingly attracted to each other since I don’t

think it’s very easy to formcovalent bonds between them.

When askedwhatwould happen if the helium atomswere to continuemoving closer together,

he noted that the interactionwould become repulsive.

Kenneth: I think you would more have a repulsive electron interaction if they got really

close to each other. Potential energywould increase as they got closer together if therewas a

high repulsive force.

Figure 2. Percent of student responses that indicated that potential energy could be stored in nuclei or stored in bonds.GC1N¼ 142,GC2N¼ 188,GCN¼ 102.



In this context, Kenneth associated repulsive interactionswith increasing the potential energy

of the system. Though he did not specifically discuss energyminimization in the context of helium

atoms, he later predicted (correctly) that forming a hydrogen bond between two water molecules

would minimize the potential energy of the system. He also discussed how as potential energy of

the systemdecreased, kinetic energywould increase, resulting in increasedmotion of the particles.

Thus, he correctly identified bond formation in the context of hydrogen bonding between water

molecules as exothermic. However, when Kenneth discussed his understanding of potential

energy at the atomic–molecular level more generally, he expressed a belief that energy can be

stored in covalent bonds.

Kenneth:Potential energy at that level [the atomic–molecular level]would be the energy of

a covalent bond for instance. The energy of that bond can be released under certain

conditions to dowork on the environment around them.There’s energy stored in that bond.

When prompted by the interviewer to elaborate on his understanding of energy in this context,

Kenneth tried to explain how energymight be stored in a bond by appealing towhat he knew about

how covalent bonds behave. He described a model in which two covalently bonded atoms vibrate

relative to one another. Referring to potential energy as “positional energy,” he described how the

potential energy of the system would increase as the atoms moved away from their neutral bond

length.

Kenneth: If it is stretched from its neutral bond length, it has potential energy because it’s

being stored and it can be released. It can heat the environment or be used to cause other

chemical changes, so it’s potential in thatway.

While Kenneth’s description of energy change in this system accounted for small fluctuations

of energy that occur as atoms within a bond vibrate relative to one another, it did not address the

question at hand, which was how energy would change if a covalent bond were broken. Kenneth

did not seem to recognize that his model failed to account for the process of bond breaking or that

his interpretation of potential energy as energy stored by a covalent bond (and thus able to be

released when the bond was broken) seemed to contradict his earlier conclusion that overcoming

intermolecular interactions would require, rather than release, energy. Kenneth did not bring up

the idea of “stored energy” in the context of helium atoms or water molecules and perhaps

associated stored energy onlywith covalent bonds.

As Teichert and Stacy have noted (2002), the idea that bond breaking releases energy is a

persistent difficulty. We believe this idea may stem in part, from students’ misinterpretation of

potential energy as “stored” energy, which as we have noted is a common curricular definition of

potential energy. For the idea of potential energy to be meaningful, it is critical that students

develop an understanding of the relationship between potential energy and electrostatic

interactions between particles. Prior to his interview, Kenneth had probably never been explicitly

asked to think about what it means to say that energy is “stored” by a bond or how potential energy

changes that occur as atoms andmolecules interact relate to energy changes upon bond formation.

Thus it is not surprising that Kenneth was unable to reconcile his understanding of how and why

bonding interactions formwith his intuitive idea that covalent bonds “store” energy.

Potential Energy as Related to Stability

The third theme that emerged from our analysis was that students commonly attributed an

increase or decrease in potential energy to the stability of the system. Students who identified the



trend that lower potential corresponds to a more stable state (and conversely, higher potential

energy corresponds to an unstable state) most often did so with little elaboration of their

understanding of the factors which contributed to the stability of the system, such as electrical

forces. For example, one organic chemistry student described her understanding of potential

energy as follows: “potential energy at the atomic/molecular level is related to stability. In the

Newman conformations, the lower the potential energy the more stable the molecule is.”

(OC, survey). Similarly, another student described potential energy at the atomic–molecular level

as “the energy of a system when it is unstable. When two atoms are close together, they have high

potential energy and thus will force apart” (GC2, survey). Though the second student seemed to

conflate the ideas of energy and stability, both responses suggest an association between lower

potential energy and higher stability of a system.

In the semi-structured interviews a number of participants used the idea of stability in

attempts to explain energy changes in atomic–molecular systems, though often without explicit

discussion of themechanisms bywhich systems become stable. That is, students rarely identified

that systems are said to be “stable” when forces acting within the system become equilibrated

such that a small change in the systemwould result in a force that returns the system to the stable

state in which the forces are balanced and potential energy is minimized. We view this

observation as potentially problematic since most students used the idea of stability to

reason about energy changes in ways that while seeming superficially correct were not

necessarily well anchored to their understanding of atomic–molecular structure and forces at the

molecular scale.

To illustrate this trend, consider Calvin and Frank, both organic chemistry students

who used the idea of stability to reason about interactions between atoms or molecules.

When asked to describe how he thought two water molecules might interact, Calvin commented

on the electronegativity differences between hydrogen and oxygen atoms and how the

electronegativity difference contributed to the polarity of the molecules. He drew two arrange-

ments of water molecules (Figure 3) to illustrate some ways that he believed water molecules

might interact.

When asked to describe how he thought potential energy of the two systems in Figure 3might

compare, Calvin asserted that the system shown in Figure 3b would have lower potential energy

than the system shown inFigure 3a.He explained his reasoning as follows:

Calvin:This one [arrangement in Figure 3a]wants to separate because positives are lined up

with positives, negatives lined up with negatives, and charges don’t like that way. And this

one [arrangement in Figure 3b] is more stable because positives are lined up with negatives

and create a chain, and that opposite attraction creates more stability than the same

attraction.

Calvin reasoned that the arrangement ofmolecules in Figure 3bwould bemore stable than the

arrangement in Figure 3a based on the fact that the interaction between the molecules would be

attractive (rather than repulsive as in the arrangement in 3a).While the particular arrangement for

hydrogen bonding in Figure 3bwould be extremely unlikely, Calvinwas correct in his assumption

that attractive interactions would lower the system’s potential energy. However, a more complete

response might also include the idea that it is the balance between attractive and repulsive forces

that occur in hydrogen bonding interaction that causes the system to be stable.

When asked to further elaborate his understanding of the idea of stability, Calvin commented

that “more stable means lower potential energy” and explained his understanding of the

relationship between stability and potential energy change as follows.



Calvin:When you have unstable systems, there’s potential energy because they want to go

to a stable system. And so they’re going to dowhatever they can to turn the potential energy

into like amolecularly [sic] kinetic energy to get to their stable system.

While earlier in his interview Calvin seemed to associate attractive and repulsive forces with

the idea of stability, he did not revisit the idea of forces in his second attempt at explaining why

potential energy would change. Instead, he appealed to a teleological explanation of energy

transformation in which he attributed change in potential energy of the system to the water

molecule’s desire to reach a certain state (Talanquer, 2007). While an expert would consider the

minimization of the potential energy of the system to be a consequence of the change in the

system, Calvin seems to suggest that stability would be the cause of the change rather than an

effect. Thus, Calvin’s explanation missing is the causal relationship between change in potential

energy and the forces present in the system.

Frank, another organic chemistry student, used the idea of stability in order to explain the

energy changes that would accompany interactions between hydrogen atoms. He described

breaking a covalent bond between hydrogen atoms as a process that would require an input of

energy and related that energy input to the relatives stabilities of species before and after

interaction.

Frank: We’ll say a, hydrogen molecule, H2, to pull those two molecules [sic] apart, it’s

gonna require energy because they’re less stable apart than they are together. And they’re

going to havemore energy for the twoof them than the onemolecule [sic] had alone.

When asked to elaborate his understanding of the term stability in this context, Frank noted,

Frank: When I think of stable, I think of low potential energy. I think of something not

waiting to do anything, something without the means, the conditions to do anything

productive forme.

Figure 3. Calvin’s depictionofwatermolecules arranged to be less stable (a) and less stable (b).



Like Calvin, Frank seemed to associate stable systems with low potential energy (and

conversely unstable systems with higher potential energy). In explaining why a system would be

stable he returned to an interpretation of potential energy as the ability to cause change or motion

in a system, which he had discussed earlier in his interview. Perhaps because the presence of

charged particles was not as readily apparent as in the context of interacting hydrogen atoms as

compared to interacting water molecules, Frank did not relate the idea of stability to attractive or

repulsive interactions.

While Frank’s explanation sounds quite appropriate, it is questionablewhether his attribution

of potential energy changes is associated with a deeper conceptual understanding of the

relationship between force, energy, and stability. Instead, the trend “more stable, less potential

energy” seemed to function as a heuristic for Frank. While heuristics such as these may be useful

in that they provide a way simplifying an otherwise more complex reasoning tasks (Maeyer &

Talanquer, 2013) it is well established that students may fail to attend to the conditions under

which a given heuristic may be appropriate and thus may be more likely to apply heuristics in

contexts in which they are not valid (Cooper, Corley, & Sonia, 2013; Maeyer & Talanquer, 2013;

Taber, 2009). While the idea of potential energy change as determined by a system’s “desire” to

become stable can be useful in easily recognized contexts (such as the familiar case of hydrogen

atoms forming a diatomicmolecule), in novel contexts it may be less obviouswhich speciesmight

be consideredmore stable.

Prevalence of Themes Across Student Groups

As shown in Figure 4, all groups of students frequently conceptualized potential energy

as stored energy or capability. While the idea of potential energy as related to stability was

less prevalent in the survey data (<10% for all groups), stabilitywas used by 12 out of 22 interview

participants when reasoning about interactions of atoms. Across both survey and interview

data, we observed that a greater proportion of students in organic chemistry courses used

the idea of stability compared to general chemistry students, almost certainly because the idea

of stability is frequently used in organic chemistry courses. Figure 4 also highlights that

very few students identified relationships between potential energy, electrical forces, and

position of interacting particles in their reasoning about potential energy (<2% of students in all

groups).

As we have discussed, each of the three conceptions of potential energy described here

(storage, capability and stability) has somemerit. However, without the associated ideas of forces

and position of interacting objects it becomes very difficult for students to form a coherent and

useful model of potential energy that can help them make sense of atomic and molecular

interactions across a variety of contexts.

Discussion and Conclusions

As highlighted by the recent Framework for Science Education (National Research

Council, 2012), energy has the potential to serve as a crosscutting concept that can be used

to predict and explain a wide range of phenomena. By understanding relationships between

energy ideas, students may be better able to use energy ideas as a tool for solving problems

and explaining phenomena (Fortus & Krajcik, 2012). In undergraduate chemistry contexts,

the ultimate goal would be to have students use the ideas of electrical interactions and potential

energy changes at the atomic scale to explain macroscopic observations such as a temperature

increase as a reaction occurs or properties such as melting point or boiling point for different

substances.



However, our findings illustrate that there may be significant challenges associated with

students’ reasoning about the atomic–molecular level that may make it difficult for students to

make these connections on their own. Instead of relying on an understanding of forces and their

connection to energy changes,we found that studentsmore often relied on intuitive interpretations

of potential energy such as the idea that potential energy represents an ability to form a bond,

to interact, or to move. Such intuitive interpretations were rarely productive tools for reasoning

about energy changes across different atomic–molecular systems. Students also reasoned about

potential energy as “stored energy” in atomic–molecular systems but often without the

qualification that potential energy is stored by a system of interacting particles based on their

relative position and charges. Especially problematic was the idea that potential energy can be

“stored” within a bond and thus released when the bond is broken. We also observed that while

many students related potential energy to the stability of the system, most did so without a

recognition that stability of a system is an effect that arises from forces and interactions between

atoms andmolecules.

Amore explicit discussion of potential and kinetic energy as models of energy at the atomic–

molecular scale may help students better connect energy ideas across scales and disciplinary

contexts. Framing potential energy as “stored” in interactions between atoms and molecules may

be especially productive since this idea can be applied to systems at both atomic–molecular and

macroscopic scales (National Research Council, 2012). However, as we have demonstrated, the

idea of “stored” energy can be problematic. If students are to productively extend the idea of

potential energy across contexts, discussions of potential energy as “stored” energy must be

accompanied by explicit instruction about how and under what conditions energy is stored. That

is, studentsmust be helped to understand that energy is stored in interactions between twoparticles

because of electrostatic forces and that a system of objects interacting in a bond ‘stores’ less

energy than separated atoms.

Figure 4. Percentage of student responses using ideas of potential energy as stored energy, capability, and stability inresponse to online survey prompt: “At the atomicmolecular level, what do you think potential energy is?”, GC1 N¼ 142,GC2N¼ 188,GCN¼ 102.



Given the great explanatory power of electrostatic interactions in chemistry (from periodic

trends, to bonding and intermolecular forces, to the energy changes that accompany chemical

processes), it is quite surprising that there is seldom an explicit discussion of the nature of forces at

the atomic–molecular scale in undergraduate chemistry courses. We believe that it may too often

be assumed that students already have appropriate prior understandings about the relationships

between forces and potential energy and thus these relationships may not be explicitly discussed,

leaving students without a coherent framework with which to make sense of these ideas. Given

that students’ prior knowledge related to potential energy may be fragmented or incomplete

(diSessa, Gillespie, &Esterly, 2004), it is critical that chemistry instructors both attend to students

prior knowledge about energy ideas and provide appropriate support for helping students make

connections between force and energy ideas. For instance, activities that engage students in

constructing models and explanations for energy changes in atomic–molecular systems may be

particularly appropriate for both eliciting prior knowledge and providing opportunities for

students tomake connections between force and energy ideas.

One promising route towards helping students develop a more coherent understanding of

energy ideas within chemistry contexts may be the use of a learning progression approach to

aligning curriculum, assessment, and prior research on students’ understanding of energy ideas.

Learning progressions represent empirically validated descriptions of pathways along which

students understanding may progress (Duschl, Maeng, & Sezen, 2011). While there is currently

no empirically validated learning progression for teaching various aspects of the energy concepts

at the undergraduate level, a considerable amount of foundational work towards the development

learning progressions for energy at the K-12 level has been accomplished (Jin &Anderson, 2012;

Lacy, Tobin, Wiser, & Crissman, 2014; Neumann, Viering, Boone, & Fischer, 2013; Nordine,

Krajcik, & Fortus, 2011). Furthermore, there is evidence from K-12 contexts that a learning

progression approach to teaching energy ideas may improve students understanding of energy-

related phenomena (Nordine et al., 2011).

Our ongoing work in this direction focuses on the development and assessment of an

evidence-based learning progression for energy in the context of an undergraduate general

chemistry course called Chemistry, Life, the Universe, and Everything (Cooper & Klymkowsky,

2012). By beginning with a discussion of energy at the atomic–molecular level and by making

explicit connections to students’ prior understanding of energy ideas, the aim is to provide amore

robust foundation for understanding discussions of macroscopic energy ideas in chemistry

contexts (Cooper et al., 2014). In order to refine learning progression approaches such as this,

morework is needed that explores how students coordinate across electrostatic, macroscopic, and

quantummechanical perspectives on energy in chemistry contexts.

Given the ongoing nature of reforms at the K-12 level, we consider a learning progression

approach to have the potential to not only help improve students’ understanding of energy topics

in chemistry contexts, but also to provide learning experiences at the undergraduate level which

will be more aligned with ongoing K-12 reforms (National Research Council, 2012). In addition,

if this approach is transferred to other college level disciplines, specifically physics and biological

sciences, it may help students make connections that are otherwise absent. Our goal is not only to

improve students’ understanding of energy in chemical systems, but also to provide a continuing

framework that students can use across the disciplines.

This workwas supported in part byNSFDUE awards 0816692 and 1122472. Any opinions,

findings, and conclusions or recommendations expressed in this material are those of the

authors and donot necessarily reflect theviews of theNational Science Foundation.



Notes1A description of the beSocratic assessment system can be found at http://besocratic.

chemistry.msu.edu/

References

Achieve, (2013). Next generation science standards. Retrieved July 02, 2013, from http://www.

nextgenscience.org/next-generation-science-standards.

Bain, K., Moon, A., Mack, M. R., & Towns, M. H. (2014). A review of research on the teaching and

learning of thermodynamics at the university level. Chemistry Education Research and Practice. Advance

online publication. doi: 10.1039/c4rp00011k

Barker, V., & Millar, R. (2000). Students’ reasoning about basic chemical thermodynamics and

chemical bonding: What changes occur during a context-based post-16 chemistry course? International

Journal of ScienceEducation, 22, 1171–1200. doi: 10.1080/09500690050166742

Boo,H.K. (1998). Students’ understandings of chemical bonds and the energetics of chemical reactions.

Journal of Research in Science Teaching, 35, 569–581. doi: 10.1002/(SICI)1098-2736(199805)35:5<569:

AID-TEA6>3.0.CO;2-N

Bruice, P.Y. (2010).Organic chemistry. (6th ed.).Upper SaddleRiver,NJ: PrenticeHall.

Bryfczynski, S. P. (2012). BeSocratic: An intelligent tutoring system for the recognition JT, evaluation,

and analysis of free-form student input.ClemsonUniversity. Retrieved fromUMINo. 3550201.

Byrfczynski, S., Pargas, R. P., Cooper, M. M., Klymkowsky, M., Hester, J., & Grove, N. P. (2012).

BeSocratic: Graphically assessing student knowledge. In BeSocratic: Graphically assessing student

knowledge. (pp. 2–7). BerlinGermany.

Cooper, M., Corley, L. M., & Sonia, S. M. (2013). An investigation of college chemistry students’

understanding of structure–property relationships. Journal of Research in Science Teaching, 50, 699–721.

doi: 10.1002/tea.21093

Cooper,M.,&Klymkowsky,M.W. (2012).Chemistry, life, the universe&everything. (pp. 1–241).

Cooper, M., & Klymkowsky, M. W. (2013). The trouble with chemical energy: Why understanding

bond energies requires an interdisciplinary systems approach. CBE Life Sciences Education, 12, 306–312.

doi: 10.1187/cbe.12-10-0170

Cooper, M., Klymkowsky, M.W., & Becker, N. M. (2014). Energy in chemical systems: An integrated

approach. In R. F. Chen A. Eisenkraft D. Fortus& J. Krajcik (Eds.), Teaching and learning of energy in K-12

education.NewYork,NY:Springer.

Corbin, J., & Strauss, A. (2008). Basics of qualitative research: Techniques and procedures for

deveoping grounded theory. (3rd ed.). ThousandOaks,CA:SagePublications.

DiSessa, A., Gillespie, N., & Esterly, J. (2004). Coherence versus fragmentation in the development of

the concept of force.Cognitive Science, 28, 843–900. doi: 10.1016/j.cogsci.2004.05.003

Duschl, R., Maeng, S., & Sezen, A. (2011). Learning progressions and teaching sequences: A review

and analysis. In Studies in science education. (Vol. 47. pp. 123–182). doi: 10.1080/03057267.2011.604476

Ebenezer, J. V.,&Fraser, D.M. (2001). First year chemical engineering students’ conceptions of energy

in solution procesess: Phenomenographic categories for common knowledge construction. Science

Education, 5, 509–535. doi: 10.1002/sce.1021

Fortus, D.,&Krajcik, J. (2012). Curricular coherence and learning progressions. InB. J. FraserK. Tobin

& C. J. McRobbie (Eds.), Second international handbook of science education. (pp. 783–798). Dordrecht:

SpringerNetherlands.

Galley, W. C. (2004). Exothermic bond breaking: A persistent misconception. Journal of Chemical

Education, 81, 523–525. doi: 10.1021/ed081p523

Goedhart, M., & Kaper, W. (2003). From chemical energetics to chemical thermodynamics. In J. K.

Gilbert O. de JongR. Justi D. Treagust& J.H. vanDriel (Eds.), Chemical education: Towards research-based

practice. (Vol. 17. pp. 339–362).Dordrecht, TheNetherlands:KluwerAcademic Publishers.



http://besocratic.chemistry.msu.edu/

http://besocratic.chemistry.msu.edu/

http://www.nextgenscience.org/next-generation-science-standards

http://www.nextgenscience.org/next-generation-science-standards

Hadfield, L., & Wieman, C. (2010). Student interpretations of equations related to the First Law of

Thermodynamics. Journal ofChemical Education, 87, 750–755. doi: 10.1021/ed1001625

Jewett, J.W. (2008). Energy and the confused student II: Systems. The Physics Teacher, 46, 81–86. doi:

10.1119/1.2834527

Jin, H., & Anderson, C. W. (2012). A learning progression for energy in socio-ecological systems.

Journal ofResearch in ScienceTeaching, 49, 1149–1180.

Kronik, L., Levy Nahum, T., Mamlok-Naaman, R., & Hofstein, A. (2008). A new “Bottom-Up”

framework for teaching chemical bonding. Journal of Chemical Education, 85, 1680. doi: 10.1021/

ed085p1680

Lacy, S., Tobin, R., Wiser, M., & Crissman, S. (2014). Looking through the energy lens: A proposed

learning progression for energy in grades. 3–5. In B. Chen A. Eisenkraft D. Fortus J. Krajcik K. Neumann J.

Nordine&A. Scheff (Eds.), Teaching and learning of energy inK-12 education.NewYork: Springer.

Lindsey, B. A, Heron. P. R. L., & Shaffer, P. S. (2012). Student understanding of energy: Difficulties

related to systems. American Journal of Physics, 80, 154–163. Retrieved from http://link.aip.org/link/

AJPIAS/v80/i2/p154/s1&Agg¼doi

Loverude, M. E. (2005). Student understanding of gravitational potential energy and the motion of

bodies in a gravitational field.AIPConferenceProceedings, 790, 77–80. doi: 10.1063/1.2084705

Maeyer, J., & Talanquer, V. (2013). Making predictions about chemical reactivity: Assumptions and

heuristics. Journal ofResearch in ScienceTeaching, 50, 748–767. doi: 10.1002/tea.21092

Nahum, T., Mamloka Naaman, R., Hofstein, A., & Krajcik, J. (2007). Developing a new teaching

approach for the chemical bonding concept aligned with current scientific and pedagogical knowledge.

ScienceEducation, 91, 579–603. doi: 10.1002/sce.20201

National Research Council. (2012). A framework for K-12 science education: Practices, crosscutting

concepts, and core ideas. Q. Helen S. Heidi &K. Thomas (Eds.), Washington, DC: The National Academies

Press.

Neumann, K., Viering, T., Boone, W. J., & Fischer, H. E. (2013). Towards a learning progression of

energy. Journal ofResearch inScienceTeaching, 50(2), 162–188. doi: 10.1002/tea.21061

Nilsson, T., &Niedderer, H. (2014). Undergraduate students’ conceptions of enthalpy, enthalpy change

and related concepts. ChemistryEducationResearch andPractice.Advance online publication. doi: 10.1039/

C2RP20135F

Nordine, J., Krajcik, J. S., & Fortus, D. (2011). Transforming energy instruction in middle school to

support integrated understanding and future learning. Science Education, 95, 670–699. doi: 10.1002/

sce.20423

Novak, J. D. (2002). Meaningful learning: The essential factor for conceptual change in limited or

inappropriate propositional hierarchies leading to empowerment of learners. Science Education, 86, 548–

571. doi: 10.1002/sce.10032

Sreenivasulu, B., & Subramaniam, R. (2012). University students’ understanding of chemical

thermodynamics. International Journal of Science Education, 35, 601–635. doi: 10.1080/09500693.

2012.683460

Storey,R. (1992). Textbook errors&misconceptions in biology:Cell energetics. TheAmericanBiology

Teacher, 54, 161–166. doi: 10.2307/4449321

Taber, K. S. (2003). Understanding ionisation energy: Physical, chemical and alternative conceptions.

ChemistryEducationResearch andPractice, 4, 149. doi: 10.1039/b3rp90010j

Taber, K. S. (2009). College students’ conceptions of chemical stability: The widespread adoption of a

heuristic rule out of context and beyond its range of application. International Journal of Science Education,

31, 1333–1358. doi: 10.1080/09500690801975594

Talanquer, V. (2007). Explanations and teleology in chemistry education. International Journal of

ScienceEducation, 29, 853–870. doi: 10.1080/09500690601087632

Teichert, M. A., & Stacy, A. M. (2002). Promoting understanding of chemical bonding and spontaneity

through student explanation and integration of ideas. Journal of Research in Science Teaching, 39, 464–496.

doi: 10.1002/tea.10033



http://link.aip.org/link/AJPIAS/v80/i2/p154/s1&x0026;Agg&x003D;doi



Tro, N. J. (2012). Chemistry in focus: A molecular view of our world. (5th ed.). Pacific Grove,

California:Brooks-Cole Publishing.

Vygotsky, L. (1978). Mind in society: The development of higher psychological processes. M. Cole V.

John-Steiner S. Scribner&E. Souberman (Eds.), (14th ed.). CambridgeMA:HarvardUniversity Press.

Supporting Information

Additional supporting information may be found in the online version of this article at the

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College chemistry students' understanding of potential energy in the context of atomic-molecular interactions