Teach my [Stoichiometry] Lesson

A few weeks ago I wrote about a new approach I tried to teaching stoichiometry, the fundamental math of chemistry. At almost the same time, I wrote a post in response to a blogging initiative launched by the MathTwitterBlogoSphere (#MTBoS). This post is a follow-up to both of those things. This week the #MTBoS asks us to post about a lesson we taught this week. What went well? What didn't? 

The Lesson

This week I taught a lesson that is part of a progression of stoichiometry lessons. In the past, I might have stood at the board and prodded my students with questions to help them lead me to the answer using a problem solving strategy that we have practiced all year. In the past couple of years, I made a presentation available to all students and they could use it (or not) to assist them as they worked through the problems while I circulated to help and answer questions. I wanted to try something slightly more differentiated and targeted this year, partly because my experiment in the stoichiometry lessons of a few weeks ago left some students really struggling.

I looked at scores from two quizzes and put my students into three groups. The smallest group was 5 or 6 students from each class whose quiz scores revealed deficits in this content. These students received small group instruction with me during my lesson. The students who did fine on the two quizzes completed the math problems with the presentation. All these students solved the same 6 problems, but some did them with my modeling and elaborations and others checked their work against a digital version of the notes. I predicted that the students who aced both quizzes were ready for more of a challenge and didn't need either my instruction or the technology assistance. I wrote a difficult problem and told them to try to solve it. Once I had the small group working on something, I could still circulate and answer questions in the two other groups. After the extension group finished solving the problem, I made the chemicals from the problem available so that they could carry out the reaction from their problem. They created a balloon full of hydrogen gas that they ignited!

Anecdotal Benefits

I saw benefits to this version of my lesson while teaching it. The group working on the extension had excellent conversations in all classes where they worked together to solve this problem, asking and answering great questions. They all arrived at the answer with minimal assistance from me; eavesdropping on their awesome conversation was spectacular! When I told them that they would carry out the experiment and light the balloon, they loved the idea of that. Still, I wasn't prepared for how much they would enjoy doing it. One student who has said very little to me all year, looked at me and said, "This is the greatest thing I have ever done."

The experiment opened up an opportunity for more great conversation. They had calculated the size of the hydrogen balloon, but the balloon did not inflate nearly as big as their [correct] calculations predicted. Why is that? They had very interesting ideas about this and it was fun to share them.

As sexy as an exploding hydrogen balloon is, my favorite benefit came in the small group setting. One student who has had a very difficult year almost always sits with students who are outpacing her in class. In the small group setting, the person next to her did not understand how to set up a problem, so she showed him. Without differentiating like this, she would not have had the chance to demonstrate her knowledge and he would not have been able to thank her for doing so, but both of those things happened during the class. How nice it must have been to go from being the person who asks for help to being the person who provides it!

The Data Don't Lie

The lesson was really fun to teach, but if it were just fun without content gains, it wouldn't have been worth it. At the end of the week the students took a quiz over the concept. I was anxious to see the scores to see if this approach had helped or (please, no!) hurt. The average score on the quiz was a 13 out of 15, right around my typical average for a quiz and just a shade higher than last year's average. Fourteen students in three classes had received small group instruction. Eleven of those students improved when comparing this quiz score to the previous two that were used to group the students. Four of those students had failed at least one of the previous quizzes and passed this one, some by earning As or Bs this time.

The Takeaway

In my classroom, I struggle to differentiate in a way that is not too hard to manage and doesn't make anyone feel badly for whatever version of the lesson they complete. I also try to keep things open-ended and challenging, but I think I do model more often than I need to, especially for students who are ready to go it along. This lesson was a step in the right direction in both of those areas, so I am going to look for ways to expand this in coming units.