Chemistry, Life, the Universe and EverythingMelanie Cooper

Department of Chemistry, Clemson University

Michael KlymkowskyBioliteracy Project

Molecular, Cellular & Developmental BiologyUniversity of Colorado, Boulder

CLUE: A New General Chemistry Curriculum

Why?

Nationally > 50% students in general chemistry are in bio-oriented majors.

Many take chemistry (only) because medical professions require it.

Who are the students in our chemistry courses?

Biology-related majors enrolled in Organic Chemistry, Clemson, Fall 2008

And most of

these are Pre-med

And most of

these are Pre-med

Angier, N. (2007). The canon: A whirligig tour of the beautiful basics of science. New York: Houghton Mifflin.

Let’s face it: chemistry has a bit of an image problem

“Chemistry is the subject that at least 6 out of every 6.0225 Americans insist they “flunked in high school”.

The boilerplate evil scientist of Hollywood is often some type of chemist….. People rant against all the “chemicals” in the environment ……”

“Chemists may be thought by adult survivors of high school to have the sex appeal of a cold sore”

“There seemed to be a mystifying universal conspiracy among textbook authors to make certain the material they dealt with never strayed to the realm of the mildly interesting and was always a long distance phone call away from the frankly interesting”

All mine (science texts) were written by men (it was always men) who held the interesting notion that everything became clear when expressed as a formula and the amusingly deluded belief that the children of America would appreciate having chapters end with a series of questions they could mull over in their own time. So I grew up convinced that science was supremely dull…… “

Bryson, B. (2003). A short history of nearly everything. NY, NY.

Is there a conspiracy involved?

“The chemist’s world is the world around us, a pampered stratum of relatively mild temperatures, and manageable atmospheric pressure, and liquid water in abundance”

“From the 115 elements you can build a near infinity of molecules, of any type you need, to get all the structural and functional diversity you can ask for. There are at least 100,000 different molecules in the human body. Some 900 volatile aroma components have been found in wine. Chemistry is molecules. We are molecules. Chemistry is a truly anthropic science.

Roald Hoffman quoted in “The Canon”

And yet…

General Chemistry Courses Emphasize

Perhaps the grim death march through units, measurement, and stoichiometry is not as productive or engaging as we might hope?

Sadler, J.R.S.T 2005 42, 987, Science 2007, 317, 457

• Stoichiometry, Stoichiometry, Stoichiometry • The structure of atoms• Bonding• Inorganic Reactions (precipitations)• Equilibrium, Equilibrium, Equilibrium

Why are we squandering our opportunities to engage students

with our subject?

Research (and experience) suggests that students get “turned off” during general

chemistry (especially the second semester)

Research (and experience) suggests that students get “turned off” during general

chemistry (especially the second semester)

Grove, N.P.; Bretz, S.L. J. Chem. Educ., 2007, 84(9), 1524-1529

Two questions:

What should students be learning?

Are they learning it?

Biological systems involve

• Relatively few elements / bond types• Relatively few reaction types• Constrained reaction conditions• Coupled, non-equilibrium systems• Intermolecular interactions (surface properties)• Hydrophobic effects (self-assembly/folding)

Many biology faculty do not apparently think so, since they “re-teach” basic chemistry in a

week or two.

Are they learning what we teach?

Growing body of education research suggests that they do not (at least not confidently enough to use it)

Why? Don’t students already know this material?

Havighurst, R. J. (1929). Reform in the chemistry curriculum. J.Chem.Educ., 6, 1126.

National Research Council. (2003). Bio 2010: Transforming undergraduate education for future research biologists. The National Academies Press

Nameroff, T. J., & Busch, D. H. (2004). Exploring the molecular vision. J.Chem.Educ., 81, 177.

Calls for reform are not new

Core principles of student learning• Identify and

address pre-/misconceptions

• Knowledge of how science is done

• Metacognition

• Context

National Research Council. How people learn: Brain, mind, experience, and school (2001). Bransford J., D., Brown A., L. and Cocking R., L. (Eds.), . Washington DC: National Academies Press

Current Gen Chem (and lets face it most chemistry) texts• Not based on research on learning• Difficult to read/bloated and full of “asides”• No narrative theme (reason to read)• No efficacy data (in fact evidence that they

don’t produce meaningful learning)• Attempt to teach process skills by using the

wrong medium

A research-based, integrated curriculum - based on emergence and evolution of life

Engaging Text

Research-based Learning Objects

Assessments

Goals

Research Base: existing and proposed research on student learning:

• Conceptual development

• Problematic Pre-/Misconceptions

• Development of problem solving expertise

• Assessment

Conceptual Change

What chemistry concepts are important in biology? (and do chemistry students understand them?)

Can we address both these and core chemistry concepts?

What order should concepts/skills be introduced?

What is fundamental/foundational and what “can wait”?

Research-validated applets – allow students to explore bond formation and breaking and the accompanying energy changes.

Research into student thinking and language / Concept Inventories elicit pre-/misconceptions

ConcepTests, conceptual assessments – check for understanding (not pre-post)

How to identify and address misconceptions?

Preliminary work

Hydrophobic effect – driver for protein/nucleic acid folding, Molecular interactions, and

micelle/bilayer formation

Bond Energy (source of chemical energy)

Chemical Energy

• How do students develop understanding about chemical energy/entropy/enthalpy, equilibrium, non-equilibrium, coupled reactions?

• Central role of bond energy – bond making and breaking

• Many misconceptions are didaskalogenic (instruction-induced), since students have no experience with bonds/reactions/etc.

http://bioliteracy.net (get an account) https://solarsystem.colorado.edu/conceptInventories/

Ed’s Tools – gather student language, begin to map student thinking

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Describe what happens in terms of energy changes during bond formation and breaking.

Describe the energy changes involved in the following chemical reactions:

(a) CCl3F(g) C(g) + 3Cl(g) + F(g)

(b) Na(s) + ½ Cl2(g) NaCl(s)

Sample open-ended questions

Sample Concept Inventory Question

Which of the following statements describes the energy changes during bond formation and breaking?  a) The energy released from bond breaking and formation is remarkable.

b) During bond formation, energy is applied into the reactant molecules so that their electrons will move around in order to form product molecules.

c) During bond formation energy is released while during bond breaking energy is consumed.

d) The reactant molecules absorb energy from their constituent atoms to form product bonds.

e) Energy is released when bonds in the reactants are broken and energy is required to build bonds.

Misconceptions % Students

Pre-instruction Post-Instruction

Bond breaking/ making 69 50

Charge and electrons 44 7

Confusing/ contradictory

25 43

General Chemistry Students (%) with Misconceptions about bond energy and its role in

chemical reaction

% Students by type with bond energy misconceptions

Chemistry level (#) %

General Chemistry (77) 50

Inorganic (13) 54

Organic (172) 65

Analytical (35) 51

Physical (16) 56

Graduate Students (21) 68

Bond-energy Concept Inventory Results

Chemistry Post-docs

What happens to the potential energy when two hydrogen atoms come together

After interaction with the “bonding applet”

Entropy driven

Micelle formation

Protein folding

Oil and water

Hydrophobic Effects

“Oil is not soluble in water, this is the main reason why water and oil do not mix. When

mixing the oil and water, the oil will not disperse throughout the water.”

Ed’s Tools question: Why Don’t Oil and Water Mix?

Oil and water

Reason % Pre-instruction

% Post instruction

% graduate students

Density 33 24 40

Words without explanation (intermolecular forces, hydrophobic, “like dissolves like”)

76 71 60

Oil and water repel 38 18 20

Intermolecular forces cant be overcome/energy (Δ H)

10 12 20

# of students who give correct explanation (Invoke G or Entropy) = 0

Why don’t oil and water mix?

A. Like dissolves likeB. Oil and water have different densities which

causes them to separate.C. There are no attractive forces between oil

molecules and water molecules, and therefore the hydrogen bonds between water molecules would require too much energy to break.

D. The entropy of the system is higher in the unmixed state, because non-polar molecules cause water molecules to cluster around them.

E. Oil molecules repel water molecules

Chemistry Post-docs

Development of structure-property relationships: using range of interactive tutorials

Macroscopic

Symbolic

Structural

Particulate

C&LL Products

• Text• Interactive applets,tutorials, simulations• Concept inventories for “foundational ideas”• Formative and summative (ACS) assessments

Todd Gatlin

Sonia Underwood

Alma Gonzales

NSF

Santiago Sandi-Urena

Nathaniel Grove

Acknowledgments

• Alma Gonzales• Sonia Underwood• Nathaniel Grove

Problem solving “plan” from a general chemistry text

• Equilibrium and non-equilibrium thermodynamics,• Entropy-driven reactions• Weak acid-base reactions• Redox reactions• Electrochemical gradient dynamics• Catalysis and enzyme kinetics• Protein folding• Dynamics of molecular interactions

Many (most?) Introductory Level Biology Courses Include:

Which of the following statements describes the energy changes involved in this chemical reaction F ICl – C – Cl (g) → C(g) + 3Cl(g) + F(g)

I Cl

a) The potential energy stored up in the reactant is released when it is converted into atomic gases.b) The energy originally in CClF3 splits into three parts and is dispersed into the three elements.c) The energy of the reaction does not really change since all the products remain gases and the number of atoms after the separation is the same as when they were together.d) As the reactant is converted into products, energy is absorbed to break bonds in the reactant.e) The decomposition is caused by heating up such as in boiling which would break the bonds holding the reactant together.

C&LL Proposed Materials

• Based on research on learning• Engaging Text – theme emergence and

evolution of life • Efficacy data will be provided• Attempt to teach process skills will be

developed via interactive materials