I fully intend to teach this lesson to additional students in the future, with very few changes.  While I would address certain procedures (such as keeping hands out of filters) more directly, I would change neither the content nor the structure of the lesson.  Based on my observations, I believe that the science and the scaffolds within the lesson are both solid and effective.

 

The changes that I would make are management based and logistical.  The clearest lesson that I learned in teaching the lesson is that expectations are critical to maintaining focus and attention.  While I would still prepare the filtration materials in advance, I would keep them out of sight until needed.  I would also spread out the workspaces to provide ample room for lab groups to work independently.  At a minimum, this would provide more space for the students to work.  Ideally, it would also reduce the reluctance of certain students to work together and make it easier for all of the students to focus.  While limited space prevented me from providing for many of these conditions in my current placement, I do not expect that the same will be true in the future.

 

Given the opportunity to teach a subsequent lesson, I would plan for the students to design and construct a second filtration system in order to test and evaluate its effectiveness.

 

I would challenge the students to draw on the observations they had made and the data they had collected while designing and testing their initial filters to design a more effective model.  The lesson would reflect the actual design process by requiring that the students connect experiences and learn from past successes and difficulties.

 

The lesson would emphasize the need to think critically, and to make reasoned choices in order to achieve a better result.  The real possibility that some second generation filters may be less effective than those the students created initially would provide the opportunity to question/analyze initial assumptions.  This is a factor in actual engineering design, where the potential for failure necessitates trial and error.  While this struggle may be frustrating, I also believe that the pay off—in terms of genuine learning—is worth the struggle.  I believe that extending the lesson in this way would help to cement student understanding of the human relationship to the water cycle, as exemplified through the role of engineers and engineering design in the water treatment process.

 

Additionally, I must admit simply wanting the students to be able to repeat the experiment.  They seemed eager and excited to try more designs.  And that is a desire that I support wholeheartedly.