Archived The Interdisciplinary Nature of Teaching Chemistry and Physics

[ezfzx]

I've often wondered what would be on a test designed by students?
If the purpose of the test is to ascertain one's conceptual mastery, what do you think should be on it?

Who knows? I might even take one of your responses seriously ...

 

[jedishrfu]

It would be limited by what the students know or think they know.

Answers to questions might be wrong as a result and other students taking the test would learn even less.

 

[ezfzx]

I would assume any student-designed questions would be based on material freshly learned, unless they had some previous experience. And if we assumed everyone had been sitting in the same class, listing to the same lecture, reading the same material ... everyone would "get it". But I know that's not true. My own understanding of physics felt slower than my classmates. I was far more visual than most. I probably would not have done well on a test designed by my peers.

I suppose what I was going for was this:
What topics do the students feel are important enough to be tested over? Would you stress graphs? Vectors? Energy conservation? Kinematics? Problem solving? Lab techniques? Error propagation?

Was there some concept that you felt was very subtle, but you were happy with yourself for finding out?

 

[jedishrfu]

Many of my misconceptions occurred in Chemistry. One was molarity vs molality . I couldn't understand the use of molality until I taught it my nieces and discovered it was temperature and pressure independent ie molarity would change with temperature or pressure due to a changing volume but molality would not. It was a subtlety that I had missed even though I knew how to compute it.

http://en.m.wikipedia.org/wiki/Molality

Another one was in vectors and the cross product. I never understood why the dot product of two vectors was based on the cosine and the cross product was based on the sine until recently when I started thinking about projections of one vector on another and realized the connections and why the cross product is normal to the two vectors. That is the value of the cross product is that part which isn't projected on either but is normal to both.

 

[ezfzx]

Good points ... though, not directly physics. I mean, we use those ideas in physics, but borrow them from chem and math.

 

[jedishrfu]

Another misconception I ran into was the notion of entropy as described in Chemistry send completely at odds with the stat approach used in physics. Being a physics major, I chose the stat approach.

 

[ezfzx]

Well, that's interesting. It's been a while since I took Chem, but it seems like when I talk to the Chem folks next door, they appear have it all consistent. But it's not like we're chatting up entropy in every conversation.

The disconnect might come from the approaches of the two sciences. Physics is VERY top-down, model-focused and idealized. Chem has a small bottom-up component, more hands-on and tends to be more pragmatic. So, it seems reasonable to me that the two disciplines are just coming at it from two different directions. I suppose if each paid more attention to how the other taught it, there might be more needed overlap.

Perhaps I should sit in on a few chem lectures ...