Moles, Formative Assessment and Moving Forward....

"What are we doing to help kids achieve?"

     Formative assessment can be a double edged sword. It can be and often is extremely helpful. Some quick short three or four well worded questions at the beginning of a unit provides information about student abilities. A teacher can skip teaching information that kids already know or the teacher can discover concepts that he or she assumed students know but do not. Formative assessment about "Moles" can provide data that is hard to deal with. Can the students handle scientific notation? How well are students at basic math skills? Are students able to use dimensional analysis? Can students reason proportionaly? Here is the really hard part...what do you do if for every question asked you get a class that is all over the map? At what point do you tell a student that he or she has some basic math skills that need to be addressed and this is chemistry class?

     The struggle can be overwhelming. It is too easy to get caught up with "paralysis by analysis". Everything can be so overwhelming that one gets stuck doing nothing or following the path of least resistance.  So, if mistakes are going to be made, why not at least try to stick with what research says works and hope for the best?

     First, research says to start with a hands on activity. We attempted to do a "beans" lab. Students found relative masses of beans and found that if they had a "pot" of beans based on relative masses of beans it was always about the same number of beans. They attempted to do simple calculations. Then we tried to compare the "pot" to "moles".

     It was a struggle. A student said that if there was a mole of marbles that it would cover the Earth nine miles high in marbles. He was being completely honest when he said he just could not conceive of such a large number and thought that it was incredible that we had a jar of sulfur that was a mole of sulfur. It is honestly difficult to reason with concepts that are so large that they are hard to imagine.

     Second, I understand that this might be a statement some have strong feelings about, but if a student shows the work, labels the numbers and explains how he or she got the answer, does it really matter what method is used? Is there really only one right way that should be accepted? Why not show several methods to the students, provide the pros and cons of each and let them use the one that works for them?

     Here is another practice that I am not sure about and am having second it O.K. to say, "We are going to do some worksheets with these problems (after experiments and demonstrations). Pretend I am stupid and show me how to solve the problems."

     Regardless...I have students with a wide variety of mathematical and reasoning skills. So the question is, where do I go from here now that we are headed into stoichiometry? Well, I have a possible place to start. I am going to tell students that we are going to cook smores. The "balanced" equation for a smore is two pieces of chocolate, one marshmallow and two small graham crackers yields one smore. I challenge my students to tell me exactly how much money I need to spend on supplies so each student gets one smore. If they do, then we will cook smores. Teenagers find that food and bunsen burners are powerful motivators.

    Last but not least...students still need to balance equations and do stoichiometry. Stephanie Kimberlin of Project TIMU developed a wonderful activity called "Balancing the Particulate Way" specifically designed to help students develop stoichiometry skills when they struggle with math. In other words....gotta keep on trying...the students are worth it.

     Do you have a mole or stoichiometry activity that works well with students?  Please comment or post it...we would love to hear from you.