Standards Addressed: The lessons in this unit meet NGSS standard MS-ETS1 - Engineering Design because they require students to consider a real world problem and then design a solution for the problem.
Students are asked to find a way to safely help frogs cross a road which requires them to take into account "relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions." Students present their projects to the class and "evaluate competing design solutions." At the end of the project we discuss the positive attributes of all of the projects to determine an optimal design. The focus standard for this lesson is NGSS MS-ETS1-2. as students develop a means through which to "evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem".
This set of lessons also meets:
NGSS MS-LS2 - Ecosystems: Interactions, Energy, and Dynamics as we review interdependent relationships in ecosystems and "evaluate competing design solutions for maintaining biodiversity and ecosystem services."
Reading a scientific article during the lesson helps to meet CCSS.ELA-Literacy.RST.6-8.4 and CCSS.ELA-Literacy.RST.6-8.10 as students examine scientific terms in context.
Students are asked to present and discuss their ideas with the class, helping to meet CCSS.ELA-Literacy.SL.8.1.
The written portion of the assignment meets CCSS.ELA-Literacy.W.8.4.
I begin the lesson by asking the students to share the various ideas they came up with in the previous lesson. At this point in the discussion I am a facilitator and I do not pass judgement on the ideas. I thank each of the students for sharing their ideas and I ask for clarification only if necessary. The students' ideas range dramatically and they are very interested in hearing their classmates' ideas. I want the students to feel comfortable sharing their ideas with one another and this opportunity helps them share information in a respectful environment.
I remind the students that while brainstorming helps engineers develop numerous ideas, engineers have to find ways to narrow down those ideas. I remind them that engineers also have to think critically and carefully about their designs. I use the example that if an engineer decided his/her first idea was pretty good and all of his/her friends thought it sounded okay without asking any questions, odds are the item that was built may not stand for long and could possibly injure people in the process. I tell the students that while their initial ideas are good, I believe that we can evaluate those ideas by asking questions and exploring new options to develop an even better design. Sometimes the process of critically evaluating our ideas and work can be painful. I tell the students that I will be asking them tough questions while they are building. I also remind them not to take the questions personally, but to keep in mind that we are seeking an optimal solution. This is a statement that I reiterate throughout the building process. This is imperative to the climate of the classroom for the rest of the year. I want the students to feel comfortable asking one another questions and being asked questions without becoming defensive about the topic.
I then lead the students in the development of a rubric that they can use as an evaluation tool for their projects. In order to develop the rubric, I direct their attention to the project guidelines and I read them aloud. I first ask the students if they prefer to operate with three or five levels of performance. The students selected five levels because they felt like it gave them an opportunity to more narrowly focus their performance levels. I then asked them if they thought it would be possible to achieve a five, the highest on their scale. As a class, they determined that fives would be perfects and though they might come close, their projects may still have room for improvement. The students created this rubric for their project. Rather than fill each section with certain performance descriptors, they decided they would like to leave the sections blank so they could record their thoughts regarding each area. I do not have the students formally use the rubric until the next class period. I do leave the rubric on the LCD screen for the students to reference as they continue to build.
I then have the students meet with their partner to build the models of their projects. I spend time with each group asking them critical questions about their projects. Again, I am careful to remind the students that my questions are intended to spur their thinking, not to make them feel inadequate. I ask the students to describe the materials their project will be made of. For instance, some students decide to make a bridge for the frogs, so I ask them what the bridge will be made of. Many times, the students had been so wrapped up in the excitement of building their models that they forgot to consider what each item represented in the real world. Several students mentioned that their bridge for the frogs would be made of concrete. I ask them to recall what the news article said regarding frogs and concrete. They will then recall that the frogs stay off of the roadways when the concrete gets hot, which could be problematic if they want the frogs to use their bridge.
To end class, I facilitate a discussion regarding the students' thoughts about me asking them questions about their projects. I begin by asking them about how they felt about the process. After acknowledging that the process was a little intimidating, I ask the students why it is necessary to ask questions about a design. To follow up, I ask if a project is ever perfect and to explain their answer. Generally the students agree that perfection is difficult to come by. I then ask them how we know if something is "good enough" and when it can be improved. This puzzles the students a bit, so I ask them to think about the actions we took in class regarding this very issue. The students will recall that we generated a rubric for assessing our ideas and agree that a similar process might be used to find, while not perfect, the best possible solution. I tell the students they will be using the rubrics to examine a classmate's project in the next class.