The new (not even slightly controversial) AP Chemistry Curriculum

Changes to AP Chemistry is a big deal, even if you aren’t a teacher or student. Many future chemists get their first taste of chemistry in an AP class or an introductory class influenced by AP Chemistry.  Many high school teachers attend AP Chemistry workshops even if they don’t teach AP.  And many AP Chemistry students will find themselves in college chemistry courses (Organic for those who pass, General for those who do not).  The AP students I get in General Chemistry always set the curve in my class.

So when the College Board (which runs AP) re-writes the curriculum, it’s a big deal for the entire chemistry community.

The new curriculum is a response to a 2002 report from the National Academies called Learning and Understanding: Improving Advanced Study of Mathematics and Science in U.S. High School.  You can read it for yourself (it’s free if you sign up for an account, but it is 300 pages..), but the gist is: AP science (1) covers too much content while skimming the practice of science and (2) spends too much time on rote methods for problem solving, what I call “calculator monkey” work.  College Board took the critique seriously and began writing a curriculum that was more oriented toward science practices and less toward calculator monkey sorts of chemistry problems.

The new curriculum (you can read the whole 109 pages here) is rooted in the chemical education literature, namely, it stresses inquiry-based approaches to teaching and stresses that students should be able to shift back and forth between different representations of a problem (particulate, mathematical and macroscopic/lab observations).  I will explore this aspect more deeply in a future post.

So what’s different about this new curriculum?  The first difference is in style.  The course is built around 6 “Big Ideas” and 7 “Science Practices”.  For example:

Big Idea 2: Chemical and physical properties of materials can be explained by the structure and the arrangement of atoms, ions, or molecules and the forces between them.

And

Science Practice 1: The student can use representations and models to communicate scientific phenomena and solve scientific problems.

Each of the Big Ideas and Science practices are subdivided into more specific statements, but I’ll gloss over the details for now.  The idea is that Big Ideas and Science Practices riff off each other to produce a set of learning objectives – things that a student in AP Chemistry should be able to do.  Take an example:

Learning Objective 4.6 The student is able to use representations of the energy profile for an elementary reaction (from the reactants, through the transition state, to the products) to make qualitative predictions regarding the relative temperature dependence of the reaction rate. [See Science Practice 1.4, 6.4]

Welcome to curriculum-speak.  In average chemist terms, that means a student should be able to use a graph like the following to explain why a reaction is fast or slow.

The fact that Reaction 1 has a greater difference in energy between the reactants and the transition state (i.e., activation energy) means that it will be slower than Reaction 2.

Incidentally, Science Practices 1.4 and 6.4 are:

Science Practice 1.4 The student can use representations and models to analyze situations or solve problems qualitatively and quantitatively.

Science Practice 6.4 The student can make claims and predictions about natural phenomena based on scientific theories and models.

So the student should be able to go back and forth between using the graph (which is the model) and a macroscopic observations (the speed of the reaction).  Thus, on the AP test a student might be asked to first analyze a set of kinetics data, then draw an energy diagram that matches the data.  Or the student could be given an energy diagram and asked to correctly associate the graph with concentration versus time data.

Probably the biggest difference is the emphasis on concepts rather than mathematics.  The rationale, coming the National Academies report, is that students often memorize mathematical routines without understanding the underlying concept.  My favorite example of this is that questions regarding the Nernst equation will no longer be included on the AP exam.  Instead, students will be asked to use LeChatlier’s principle to reason about whether the potential of an electrochemical cell will increase or decrease based on the concentration of reactants and products (Learning Objective 3.12).

Personally I think this is a great change.  My undergraduate mentor Vicki Colvin always made the point that we would forget the math but remember the concepts.  And she was write.  I can’t solve the Schrödinger equation from memory anymore, but I really understand wave-particle duality (well, as much as anyone understands it).  However, many people are pretty upset about this.  I’ve been in more than one presentation where people started yelling.  The feeling (which is reasonable) is that we are dumbing down AP Chemistry.  I think that is not fair.  Take for example Learning Objective 6.17.

LO 6.17 The student can, given an arbitrary mixture of weak and strong acids and bases (including polyprotic systems), determine which species will react strongly with one another (i.e., with K >1) and what species will be present in large concentrations at equilibrium.

No where do the Learning objectives say that students should be able to calculate the pH at an arbitrary point on a titration curve.  But frankly, the above is just as hard (notice the word “arbitrary”!), requires more understanding than memorization, and is more useful to a student going on to Organic Chemistry anyway!

The new curriculum is going to take a while to digest, and a few years of difficult adjustment, as in painful-to-watch-butterfly-struggling-out-of-a-chrysalis kind of difficult adjustment.  It is my goal to write a series of posts on this blog that help explain the curriculum in more depth, both for AP teachers and chemists in general.  It is my hope that these posts help alleviate just a bit of that adjustment.

Thoughts and Comments?  Either comment below or find me on Twitter @SGPrilliman.

Disclosure:  I am an AP Chemistry consultant and a reviewer of AP Audit syllabi.