Wednesday, September 17, 2008

An analogy is sort of like a....

I'm a big fans of analogies in teaching. I think they can be useful at simplifying complex concepts. They help by putting the general ideas of a concept into more familiar forms. This is gives the student something to grasp and contemplate. The ultimate goal is that the simplified version incubates and eventually provides a foundation for the understanding of the complex concept.

The danger is that the student never gets past the analogy, and the full understanding never develops. So, analogies must be used carefully and judiciously.

With that said, I like to use analogies using kindergarteners (figuratively, not literally).

For example (my apologies to any non-chemists; this is going to get nerdy), I use kindergarteners to explain the stability provided by resonance.

The following carbanion is very unstable and highly reactive because the charge is localized on one carbon.
Whereas, this next molecule, while still quite reactive, is more stable and less reactive because the negative charge is delocalized through the pi system.

The first structure is analogous to being locked in a small room with 20 hyper adn overly energetic kindergarteners. That would be a high stress and uncomfortable situation for everyone involved. What the kindergarteners need is room to run. The second structure is analogous to being in a gymnasium with the same 20 kindergarteners. When the kindergarteners have room to run around, things are a lot less stressful. In other words, kindergarteners are nonbonded electrons.

10 comments:

Ψ*Ψ said...

That's a good one! I may steal it when I TA. :)

the other anonymous said...

Currently I use a similar analogy for size effects in basicity [conjugate or otherwise] by discussing MTV Cribs. However, this analogy is not going to last much longer as the students get younger. I am not willing to make analogies to many of the current MTV shows as I really like my job...so I may adopt the kindergarden approach. Thanks!

Gerhard said...

that's a great analogy... and it brings tears (almost) of nostalgia to my eyes remembering the Organic days. I am taking Biochem 1 right now and it is not going well (i kind of hate it). My professor makes fun of Organic and i dont know how long i will be able to hold myself before i snap at him in class.

Chemgeek said...

"My professor makes fun of Organic.."

I cannot understand that. Biochem IS organic chemistry. Except, of course in the hands of a biologist.

My totally biased opinion is such that Biochemistry is best appreciated and understood when the Organic Chemistry is stressed and loved.

Chemists should teach Biochemistry.
Biologists should teach Biology.
That's my opinion.

Gerhard said...

chemgeek you are absolutely right...

My professor did his BS in Biology and PhD in Biochemistry... so, to me he is a biologist that has an office in the chemistry department at my school.

I have to memorize the 20 amino acids by Monday for my first test. I hate memorizing.

milkshake said...

here is a reliable method how you prepare for the test, by learning in your sleep - Sleep with your teacher!

Lisa-tastrophies said...

I love it. I wish I had had you as a chem prof instead of Dr. Worbled-all-his-words. Not only do I now understand resonance, but kindergarden kids as well!! Now if you can only explain seventh graders and their attraction to throwing things, the opposite sex, Soulja Boy...

the other anonymous said...

gerhard,

I had Biochem taught by a "chemist" and still had to memorize the 20 amino acids. This is no different than memorizing the common organic functional groups [which my students had to do by the second day of class]. There are some things [vocabulary]that must be known to be able to converse in the apporpriate language.

A biochemist in a chem department is a chemist.

A good friend of mine teaches at another small-ish college in a bio department, but her BS is in chem...she is a biologist, but when she taught here in our chem department she was as chemist!

Chemgeek said...

How can anyone be attracted to the tripe that is Soulja Boy. I cannot explain that one. Maybe it's the crack cocaine.

Lisa-tastrophies said...

Chemgeek:
I know, it's totally wrong, but the kids LOVE it. I want to warn them that it's their version of New Kids on the Block, but hey... we had to learn it the hard way, I guess they will too.