A Journey of Student Understanding in General Chemistry Alexander Grushow Associate Professor (and Chair) Chemistry, Biochemistry & Physics Or understanding how students learn chemistry

General Chemistry CHE 120 is a pre-requisite for second semester general chemistry (and organic chemistry) Taken by almost all science majors About half are freshman Most will not be Chemistry or Biochemistry majors

Dread of a Chemistry Class Lots of information Lots of problems to do Lots of formulas to remember Lots of information to assimilate Mechanism to assess achievement is to see if students can do a problem based on any of the above

Periodic Trends How does atomic size change as you go L-R in a row? How does atomic size change as you go down a column?

A Change in Teaching Strategy (1998) Began using inquiry-based techniques in the classroom. Students use data and a specially developed line of questioning to develop conceptual understanding. Students (should) learn how to apply concepts to develop new knowledge and answer questions.

How do I assess this? –Not drill & kill –Not basic recall –Not even general solution answers to “typical” problems Need a different assessment mechanism Surface Learning vs. Deeper Understanding

Discussions of teaching strategies Forum for understanding student learning behaviors Methods for classroom evaluation Assessment of student understanding BRIDGE provided:

Layered and connected assessments Assertion - Reason questions Na + is a smaller ion than Br –. BECAUSE The first ionization energy for a Na atom will be larger than that of a Br atom. a) True, false **** b) False, true c) False, false d) True, true e) True, true and correct explanation

Layered and connected assessments Assertion - Reason questions Na + is a smaller ion than Br –. BECAUSE The first ionization energy for a Na atom will be smaller than that of a Br atom. a) True, false b) False, true c) False, false d) True, true **** e) True, true and correct explanation (version 2)

Layered and connected assessments Assertion - Reason questions Na + is a smaller ion than Br –. BECAUSE The valence electrons in Br occupy a shell that is further from the nucleus than the valence electrons in Na. a) True, false b) False, true c) False, false d) True, true e) True, true and correct explanation**** (version 3)

Layered and connected assessments Assertion - Reason questions In a closed gaseous system at constant volume, an increase in temperature leads to an increase in pressure. BECAUSE At higher temperatures gas molecules hit the container wall more often. a) True, false b) False, true c) False, false d) True, true e) True, true and correct explanation (another example)

Deeper explanations Completely answer two of the following four – in the spaces given. a) The sugar sucrose (C 12 H 22 O 11 ) readily dissolves in water, yet it is not an ionic molecule. Explain how this happens. b) Why do you feel cold when you step out of the shower or the swimming pool before you dry yourself off? c) Why does water boil at a lower temperature in the Rocky Mountains? d) Cooking grease does not dissolve in water. How does soap serve to make grease soluble in water?

Lessons Don’t swing the pendulum too far in one direction. Some students can only do recall problems, however this is also an important skill. It takes longer to develop or score an assessment for deeper learning.

Questions? Alex Grushow: