In Summary – Khan Academy for Organic Chemistry
In six previous posts I went through all 73 videos by Khan Academy for organic chemistry. In this final post I wrap up what I’ve learned from watching them, from the perspective of someone who teaches introductory college-level organic chemistry.
Six previous posts:?[1?2?3?4?5?6]
Contents
1. What’s Great About Khan Academy?
First of all, KA gets one really big thing right: teaching a subject as a series of 10 minute videos that gradually walk through a subject. There is a huge desire for this type of instruction and the value of discovering a popular working model for delivering educational videos cannot be understated.
His style is also very approachable and non-threatening. He doesn’t make you feel stupid. This alone is a huge part of the appeal. The tools he uses are very simple and accessible to everyone. He’s also an excellent illustrator.
Thirdly, I think it’s commendable that Sal Khan just decided to start making videos on a lot of topics without asking anyone’s permission. In some circles, his videos have been unpopular with academics. Here is a particularly lazy criticism of KA. Memo to instructors who complain about KA: you have the tools to make better videos: why aren’t you doing it?
What Does Khan Academy Cover?
I count 73 videos for organic chemistry.
These can be broken down into the following categories:
Nomenclature [27]: Alkanes, alkenes, R/S nomenclature, E/Z nomenclature, alcohols, ethers, epoxides, benzene derivatives, amines, aldehydes, ketones, carboxylic acids, anhydrides, esters, amides, acyl chlorides
Structure and bonding [5] hybrid orbitals, pi bonds, alcohol properties [hydrogen bonding], resonance, Huckel’s rule
Conformations [3] Newman projections [2 videos], chair/boat shapes for cyclohexane
Stereochemistry [4] Intro to chirality, chiral examples (2 videos), enantiomers/diastereomers/constitutional isomers
Reactivity: [8] mechanisms, Markovnikov’s rule, steric hindrance, sn2 stereochemistry, solvent effects, nucleophile strength, nucleophilicity vs. basicity, carboxylic acid derivative reactivity
Reactions: [24] HBr with alkenes, H3O(+) with alkenes, polymerization of alkenes w/ acid, SN2, SN1, E2, E1, free radical alkane chlorination, epoxide ring opening, bromination of aromatics, Friedel Crafts acylation, keto-enol tautomerism, acid-base of carboxylic acids, Fischer esterification, acid chloride formation with SOCl2, amide formation from amine and acyl chloride, aldol reaction.
Addenda [2]
What does a typical introductory organic chemistry course cover that is NOT included in Khan Academy?
If I had to name my top 10 omissions, they would be this:
no discussion of organic acids and base; i.e acidity, basicity, conjugate acid, conjugate base, pKa, how to determine if an acid base reaction is favorableevaluation of resonance forms; what makes one resonance form more stable than another? Not discussed.no discussion of the stereochemistry of the E2 reactiononly 3 alkene addition reactions covered [out of >15] ; no examples with stereochemistry. Missing examples like bromination, hydroboration, epoxidation, etc.no discussion of alkynes or their reactionsno discussion of carbocation rearrangementsno discussion of oxidation/reductiononly one video devoted to the concept of aromaticity, not enough to understand it; only 2 reactions of aromatic derivativesonly 3 videos on reactions of aldehydes, ketones, and carboxylic acid derivativesno discussion of the Diels-Alder or related reactions; no discussion of molecular orbitalsOf the material covered by the KA videos, what’s done the best?
The videos on nomenclature are useful for those who have never encountered these functional groups before. They provide accurate methods for naming these molecules. There was only one major mistake and this was corrected. A few minor mistakes (see notes on individual videos).
The videos on structure and bonding, including hybrid orbitals were done well.
The drawings of Newman projections were done well and have nice descriptions of how to convert a line diagram into a Newman projection.
What are the biggest weaknesses? What could be done better?
The videos on reactions tend to be shallow. There is a lot of imprecise language (e.g. “guy” instead of, say “nucleophile”). Chemical reactivity is? largely explained in an ad hoc fashion rather than in a way that ties back to fundamental concepts of physics. ?There’s an opportunity to explain a lot of organic chemistry by understanding the key factors that stabilize negative and positive charges; that isn’t done here. Arrow pushing is not done correctly. Stereochemistry? is arguably the major theme of first-semester organic chemistry, but its involvement in reactions is almost completely ignored.
What the videos really lack is a consistent description of chemical reactivity rooted in a small number of fundamental physical principles.
How Useful is Khan Academy For A Typical College Student Learning Organic Chemistry?
As they stand right now, KA videos are in no way a standalone alternative to a college-level course in introductory organic chemistry. If you watch all 73 videos, you will in no way have “learned” organic chemistry.
They are a useful supplement for nomenclature, structure and bonding, and some aspects of conformations.
For someone who finds their university lecturer intimidating, the videos on reactions and reactivity can be a light introduction to some of the topics covered in an introductory course.
Towards Version 2.0
Two questions for the future:
1) What is the minimum number of 10-15 minute videos required to teach the core concepts of Org 1 and Org 2 in a manner that would, say, prepare students for a standardized exam like the ACS?
2) What is the optimal order of those videos? Can we test outcomes to see if there is an optimal way in which these topics can be presented?
I look forward to further improvement of the organic chemistry video content at KA.
Tagged as: khan academy, video
Early morning in Jerusalem, 2010