Engineering Earthquake Structures: Day 4
Lesson 6 of 7
Objective: Students will be able to analyze textual evidence in order to design a structure that can survive seismic waves. Students will also be able to describe the difference between an analog and digital signal.
Over the course of 4 – 5 days, students design earthquake resistant structures based on their research of seismic design principles. Along the way, students utilize scientific text strategies, engage in scientific discourse based on evidence, experience the engineering design process and are introduced to the advantages of digital vs. analog signals. Components of this lesson connect to the following NGSS and Common Core Standards:
MS-ETS1-1 Define the criteria and constraints of a design problem with sufficient precision to ensure a successful solution, taking into account relevant scientific principles and potential impacts on people and the natural environment that may limit possible solutions.
MS-ETS1-2. Evaluate competing design solutions using a systematic process to determine how well they meet the criteria and constraints of the problem.
MS-ETS1-3. Analyze data from tests to determine similarities and differences among several design solutions to identify the best characteristics of each that can be combined into a new solution to better meet the criteria for success.
MS-ETS1-4. Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process
MS-PS-4-2 Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.
MS-PS-4-3 Integrate qualitative and technical information to support the claim that digitized signals are a more reliable way to encode and transmit information than analog signals.
On day one, students analyze text so that they can obtain and evaluate information (SP8) and engage in evidence based discussions (SP7).
Day two, students use a design matrix to determine which design solutions meet the criteria (ETS1-2) and begin testing their designs on the shake table.
On day 3, students begin to shake their initial prototypes and collect qualitative and quantitative data to create new design solutions. In addition, they work on generating questions and engage in scientific discourse as they explore connections to wave properties as the listen to the "song" or "sound a comet makes" that was collected by the Rosetta probe that landed on Comet 67P/Churyumov-Gerasimenko!
On day four, as students test their earthquake resistant structures they improve their designs based on the results (ETS.1). Moreover, students compare their results with other groups and designs to incorporate all successful components into a “super design” (ETS1-3). In addition, students are introduced to the difference between an analog and digital signal.
Day five of this lesson asks students to look at real world constraints and impacts. After developing their classroom prototype, students consider real world implications to society and the environment. They recognize that technologies have limitations and that while prototypes meet our societal needs and wants, they also have short and long term consequences. During this lesson, students further their understanding of analog and digital signals as the teacher takes the students through a visual model/analogy with a children's swimming pool!
Ask students, “What are you going to learn today?”. Students should respond by stating something connected to the NGSS Essential Question (I keep this posted on my front board.). Thus, students might say, “We need to answer the question, what are the characteristic properties of waves and how can they be used in the world?” .
In a previous day of this project, students self-assessed their level of mastery pertaining to how scientists and engineers use waves in the real world. On this day, ask students to rank themselves again, either on their fingers or verbally. Discuss as a class how this number has changed from earlier in the week. Ask the students to share if that number had increased or stayed the same. Hopefully, they share that it has increased. Follow up by asking them to share some knowledge or understanding that they have gained during this engineering design challenge that demonstrates an understanding of how engineers might use their knowledge of waves to solve problems in the real world.
Provide students with the short article about radio waves from WGBH / Public Broadcasting System. Ask students to “talk to the text” as they read the article and work through the “Ladder of Discourse”. As a class, have students share some connections they made at every level of the ladder. The Ladder of Discourse includes four levels of connections that students make when reading. Students talk to the text as they underling, highlight, question, and write in the margins about their thinking when they are reading. These levels include "Tweets" (surface, text to self connections), "Huh?" (questions about content or vocabulary), "Found it!" (using context clues to find answers, or making connections to science content they have already learned), and "Discourse" (making connections beyond the text or identifying testable questions related to the text). (This was only a brief summary of the "Ladder of Discourse". For more information on the Ladder of Discourse, see this introductory lesson and this earthquake lesson.)
Make sure that during the discussion that students connect to the wave properties that are important in the difference between AM and FM radio. It is important for students to pull from the text that AM waves have adjusted amplitudes while FM waves have adjusted frequencies. Students find it fascinating to see that wave properties are not just words to memorize; they are actually properties that we use in our technologies in everyday life!
Then, explain that waves are used to send signals that communicate information. A radio is one example of this. Further explain that not all signals and messages are the same. Some signals are analog and some signals are digital. Ask students to share what they think of when they think of analog signals and digital signals. Explain to the students that we will be investigating what this means over the next couple of days. Show students some picture examples of analog vs. digital devices.
One quick place to find a few pictures of objects using analog and digital signals is at Sparkfun created by Juan Pena.
Another picture I use comparing analog and digital television can be found at PBS.
Finally, to introduce the difference between these two types of signals, play this video.
On this fourth day of the challenge, students should be working towards creating their second or third prototypes. Before beginning, have each group meet with a different group to share their qualitative and quantitative data as well as strategies that they have found work the best (If you followed the lesson plan for Day 3, make sure that they meet with a different group than they met with during the "Closure" of that lesson). The NGSS emphasizes that engineers use data collected to make improvements in their designs. Emphasize to the students that it is not “cheating” to share ideas; instead, scientists and engineers analyze and use all data to make improvements and form new conclusions. Lastly, remind the students that before they can build a new prototype, they must show the client (you) the qualitative and quantitative data they have collected on their previous prototype and describe the improvements and reasoning behind the changes they are going to make in their next design. (This step is important! Students will rush and build without planning without this step. They need to be held accountable for using data to make improvements to address the standard MS-ETS1-3.)
Students should begin creating successful structures on this day!!
Below are some examples of student work. Notice that students drew detailed sketches with labels highlighting their design principles. Also, in the research chart, students wrote the principle, the website they got the resource from, and information about how that seismic design principle would be utilized in their design. In some instances, students use draw pictures to demonstrate their "Structure Design Choice".
The second page of the student document includes the student's completed design matrix. Notice that the student wrote the seismic design principles that her group found most important and that she ranked every member in her group's design. In the bottom data table, the student drew a quick sketch of each design, recorded the time the structure lasted on the shake table, and then provided qualitative observations during the shake. For example, the student explained that in the first design, the joints were not strong enough and in the second design the sand bag was not secure so the design became unstable. Another notable aspect of this student's data table is that each new design makes a change based on the qualitative observations from the row above. For example, in the first row the student notes that the joints weren't strong enough. Then, the next design shows more marshmallow support at the joints. In the second row, the student notes that the sand bag was loose in their qualitative observations. Then, the third design included a platform to secure the sand bag. This is a great demonstration of using data to improve design.
After clean up, have the class as a whole share their best design solutions and principles that they have found successful. Remind them that the next class period will be the last day to build and test.