Term III Science: Lesson Background & Analysis
I planned a lesson on the water treatment process—focusing on water filtration and the design of water filters—to a small group of approximately six fourth grade students.
My goal in teaching this lesson was to supplement/compliment what the students were learning in class by allowing them to engage in a deeper exploration of the human relationship to the water cycle. I sought to emphasize this connection through the inclusion of an engineering design component.
I initially struggled to plan my lesson, because there is a highly structured science program in the classroom. The students had been studying the water cycle since September, and conducted frequent investigations involving stream tables. While I aspired to plan something more hands-on and application based, I was also wary of straying too far from the curriculum. I ultimately selected water filtration as an appropriate alternative. The connection to the water cycle is explicit, and also ties into a field trip that the students took to the Fairmount Water Works earlier this fall. During the trip, the students learned that the Water Works had closed because it was exclusively a pumping station and did not have the capacity to filter/treat or purify water.
However, when it came time to plan my lesson I was torn once again. As I researched filtration, its place in the water treatment process, and how to demonstrate it, it began to seem like too much to tackle in forty-five minutes; I did not want to overcomplicate or oversimplify the lesson. I decided to take my lead from an introductory genetics lesson that was demonstrated in science methods class. The professor explained that it is appropriate for teachers to be explicit with students that an explanation is simplified, and intended to expose the underlying concepts. I plan to follow this approach by stating explicitly that our demonstration will be simplified, that we will be focusing closely on one step in the water treatment process, and emphasizing that we will not be disinfecting the water.
My final struggle was deciding whether to structure the lesson as a demonstration or to challenge the students to design their own water filters. I ultimately chose to combine these options by conducting a demonstration with the group to explain the design/testing processes as an introduction to a student design challenge.
Context & Beliefs
Initial Impressions
I feel that the greatest strength of the lesson was that the students seemed excited to do science. From the moment that we entered the library, the students were ready to explore and begin an activity. They made strong personal connects to water use and referenced their trip to the Fairmont Water Works during the introductory portion of the lesson. Following the design portion of the lesson, all of the students seemed eager to repeat the activity. While we did not have time to do so, five of the six students kept their instruction sheets so that they could repeat the experiment at home. The students seemed engaged and focused while discussing their observations and analyses, and shared some very nuanced insights. Throughout the lesson, the students appeared to be engaged and to be having fun. Importantly, they also appeared to be learning.
Observations of Student Learning
Reviewing the students’ written work and listening to the recording of the postlab discussion, greatly enhanced my understanding of the students’ experience by:
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allowing me to see the lesson from multiple perspectives;
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enabling me to focus on details that I had missed in the moment.
My analysis (as detailed below) led me to believe that:
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the lesson presented an appropriate challenge;
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the material/content was solid;
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the students were engaged in real science;
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the students learned, and enjoyed themselves in the process.
Written Work:
Reviewing the students written work revealed:
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a high level of attention to detail;
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while work varied between students, but very astute observations overall;
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the students identified aspects of the activity that had not occurred to me as I planned/taught the lesson
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e.g.: predictions/observations relating to how the filter materials were altered after use;
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deep analysis;
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well-formed predictions and observations [see image below]
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Prediction: filtering “might make it clearer”
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Analysis: similar because clearer, different because the filtered water was clearer and filtered more quickly than she had expected
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 Student predicted how the filter would be effected. |
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All but one of the students wrote that s/he would change at least one of his/her three materials when constructing a second filtration system. The sixth was satisfied that her filter had been effective. Her filtration system and filtered water are pictured to the left and below, respectively.
Water Filter Design Challenge Written Work
Recording of Postlab Discussion:
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Great discussion
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Students expressed their observations eloquently
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They made comparisons between filters
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Identified a connection between which materials a group had selected and the order in which they were layered in the filter
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As the students explained to me during the discussion:
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two of the three groups used/chose the same materials, but arranged them differently in their respective filters
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members of both groups observed and mentioned that the order in which they had chosen to layer the materials had affected their results.
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I had not made this connection independently; I was too focused on teaching. To say the least, I was impressed by the students' insight, and the clarity with which they were able to express their observations and analysis.
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Additionally, while I had only instructed the students to make predictions and observations relating to the water, the majority also focused on how the filtration materials would be/were effected.
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As we concluded the discussion, the students asked to remove the used filter layers from the funnels in order to examine them more closely.
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I gladly upended one of the filters onto a paper plate. [pictured right]
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Water Filter Design Challenge Post Lab Discussion
I have been in the classroom since September, and attended as many of the class's science lessons as possible. While the students often participate in hands-on activities and labs, this was the most science-rich, in depth discussion that I have heard. And that was equally--if not more--to the students credit as it was to my own.