OrganicPad: a tool to investigate the development of representational competence in chemistry

Transcription

1 OrganicPad: a tool to investigate the development of representational competence in chemistry (and a framework for future graphical metacognitive activities) Melanie M Cooper et. al.

2 Lewis Structure the most common structural representation

3 Structure property relationships lie at the heart of chemistry C 2 H 6 O Intoxicating liquid Bp 78 C, Gas at room temp Bp 23 C,

4 OrganicPad Cooper, M. M. et al. Chem. Educ. Res. Pract. 2009, 10,

5 OrganicPad: multiple uses Classroom interactive feedback Tutorial mode Quiz mode Analysis features Student actions stored in a database Modeling of student responses Playback

6 Ongoing Investigations How do students draw Lewis structures (in the wild) Why do students think they are learning to draw structures What information can students determine from structures? What interventions are effective? Which representations do students choose to use how does the choice of representations change over time. Does the choice of representations affect outcomes (eg ability to predict products) Can students use information contained in structures to predict future events? (reaction products) Does the use of mechanisms affect student success?

7 Why do students have difficulty drawing Lewis strcutures?

8 Four decades of literature, > 20 papers in J. Chem. Educ. alone, on improved methods for teaching Lewis Structures Most feature some kind of rule system if the rules are followed, difficulties with student understanding should not arise. Packer, J. E.; Woodgate, S. D. J. Chem. Educ. 1991, 68,

9 Well lets just see shall we?

10 Organic Chemistry Students (N=70)

11 Comparing 1 carbon vs. 2 carbon Chemical Formula % Correct 1 carbon 76 2 carbon 34

12 Comparing CH 4 O vs. CH 3 OH Chemical Formula % Correct CH 4 O 55 CH 3 OH 88

13 CH 3 OH Markov Model 13

14 CH 3 OH Markov Model 14

15 CH 4 O Markov Model 18

16 CH 4 O Markov Model 18

17 Home Grown Strategies Trial and Error Connectivity Symmetry

18 Why aren t students following the rules?

19 Why do students think they learn to draw Lewis structures? Recall the ONLY reason would be to connect structure property relationships

20 From Students open interviews and open ended responses: What information can be obtained from Lewis structures? Lost in Lewis Structures Cooper, M. M.; Grove, N. P.; Underwood, S. M.; Klymkowsky, M. W. J Chem Educ, In press Information General Chemistry (%) N=32 Organic Chemistry (%) N= 134 Graduate Students (%) N=10 Structural information obtained from Lewis structures Chemical Information obtained from Lewis structures

21 From Students open interviews and open ended responses: What information can be obtained from Lewis structures? Lost in Lewis Structures Cooper, M. M.; Grove, N. P.; Underwood, S. M.; Klymkowsky, M. W. J Chem Educ, In press Information General Chemistry (%) N=32 Organic Chemistry (%) N= 134 Graduate Students (%) N=10 Structural information obtained from Lewis structures Chemical/Physical Properties obtained from Lewis structures

22 Meaningful learning The road from C 2 H 6 O Properties: (Liquid with high boiling point (H bonding), both acidic and basic properties, susceptible to nucleophilic attack when protonated, etc). Is difficult, complex, counter intuitive, and all too often meaningless to many students Lost in Lewis Structures Cooper, M. M.; Grove, N. P.; Underwood, S. M.; Klymkowsky, M. W. J Chem Educ, In press

23 We are currently developing and assessing more meaningful strategies to learn these skills

24 Investigations into how organic chemistry students use mechanisms

25

26 0.083 (4) (4) 1.00 (66) (48) Alkene (8) (18) Acid (5) C (4) 0.50 (9) 0.56 (5) Final 0.53 (35) (17) 0.24 (4) Water (12) (18) 45.5% (30 out of 66) do not engage in the activity 15% (10 out of 66) add curved arrows afterwards 7.6% probability of proceeding via a chemically appropriate pathway

27 Overall: p = 0.873

28 Transfer Task Use of mechanism does not appear to affect the correct prediction of products for known reactions What about prediction of novel reactions?

29 * *p=0.011

30 Future Directions: Web based

31 BeSocratic A free form graphical representation system designed to recognize and respond to student inputs and common mistakes.

32 BeSocratic Prompt 1: Please draw a representation of the distribution of energies of helium molecules at 200K (don t worry about putting units on the axes just draw what you think the curve would look like)

33 BeSocratic Prompt 2: Now please draw a new curve to show what happens to the kinetic energies of the gas molecules if the temperature were increased to 300K (or the molecular mass were to increase/decrease)

34 Acknowledgements NSF REESE NSF CCLI Sam Bryfczinzki Roy Pargas Sonia Underwood Nathan Grove Mike Klymkowsky

35 Examples of Home Grown Strategies Connectivity Well it has two carbons that are going to be attached to each other; it s gonna be a carbon chain. (Libby, General Chemistry Student) C 2 H 6 O

36 Examples of Home Grown Strategies Connectivity I always feel like the most common way would just be in one chain with all the main atoms in one row just write it all out? (Jack, Organic Chemistry Student) C 3 H 7 NO

37 Examples of Home Grown Strategies Symmetry symmetry always seems to lead to the right answer with chemistry it seems like it would be stable if it were more symmetrical (Jack, Organic Chemistry Student) Problems (Ben, General Chemistry Student)