This lesson is a continuation of A Place in the Shade. During that lesson, students designed structures to shade an ice cube to slow its melting. This lesson give the students the opportunity to make revisions. To begin the lesson, I remind the students of what we did in the first lesson. Working with the NGSS Design and Engineering Practices, it is important for students to have the opportunity to revisit the models they created and have the opportunity to make revisions.
The other day, we made structures to shade an ice cube so it would not melt as quickly. Today, we are going to trying to improve those structures. A good engineer looks at what went wrong and tries to make adjustments so the structure functions better. I want you to get your structure and get back together with your group. Get out a piece of paper and sketch out what improvements you are going to make to your structure. You may want to completely redo your structure or you may just want to make improvements or enhancements to your structure. So let's move into our groups and get started.
The above materials are placed in a supply station. The students can freely access the materials in this station to create their structure.
I say to the students, Now, take a look at your structure, what improvements do you want to make? How could you improve your structure? Draw out your plans on a piece of paper.
The students begin working on their plans. This is not easy for the students, but it is important that this step is included in the process. I want my students exposed to the NGSS Engineering and Design process. As they mature and have more exposure to this process, they will improve their planning skills. I am very hands-off at this point in time. I may ask clarifying questions but I want them to plan this without my help. See video.
When the students have completed their plans, I have them present them to me and explain their improvements. It is then time to move into our "create" step in the process.
During this step, the students create improved structures or refine their existing ones. I remind them to use their plan to help guide their construction. I assist the students by tearing off pieces of tape and holding pieces together while the students connect them. I needed to send a firm ending time, as the students continued to make revisions on their structures. In some cases, the revisions most likely reduced the effectiveness of the structure. As the students are working, I ask them questions to have them express the rationale behind the features of their structure. See video.
We then move into the trial section of the lesson.
To test our structures, we go outside and find a sunny location. The students place their structures in various places in the sun. I check to make sure that none of the structures are in the shade. I then place an ice cube in a zipper bag in each structure. The control ice cube is placed in the sun without any kind of protection. I notice a big difference in the structures from those the students created in the previous. There was substantial improvements in the structures. Click to view the structures created in this lesson: Structure 1 Structure 2 Structure 3 You can compare these structures to ones made in the first lesson: Previous Lesson Structure 1 Previous Lesson Structure 2 Previous Lesson Structure 3
We then wait for the control cube to melt (The students play on the playground while we are waiting). When the control cube is completely melted, the test is done. We check the cubes in the structures to see if their is any of the ice cube left. We then rank the structures for effectiveness based on the size of the ice cube. After we have done this, we move inside for discussion.
We bring the structures back inside and discuss their success.
After the discussion, we move into the lesson closing.
Because I want to encourage my students to continue to engage in engineering activities, I ask them to do an "assessment" of our engineering and design lessons. I have them get with a partner and discuss the following questions:
I invite a few students to share their responses with the whole class.