Author Technology and Engineering Teacher - Volume 79, Issue 7 - April 2020
PublisherITEEA, Reston, VA
ReleasedMarch 18, 2020
Technology and Engineering Teacher - Volume 79, Issue 7 - April 2020

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Students often mention that their ideas have changed because the model they drew on paper during Day One did not translate well to real life.


Next Generation Science Standards (NGSS) notes that all students can benefit from knowledge of engineering design practices: defining problems, developing solutions, and optimizing (NGSS, 2013). Design activities provide a useful vehicle for teaching engineering design practices because they reflect the systematic problem solving that characterizes the work of engineers (NRC, 2009). However, it is becoming increasingly important for students to go beyond engaging in design by reflecting upon the nature of engineering (NOE) and wrestling with questions such as, “What do engineers do?” and “What is engineering?” (Pleasants and Olson, 2018).


This article describes an activity in which middle school students are asked to create a product to help a fictional bank sort coins. This design activity can be used to meet NGSS middle school engineering standards three and four (MS-ETS1-3, MS-ETS1-4) that target optimization and the iterative nature of engineering (see NGSS Table 3 on page 24). Over the course of three 45-minute class periods, students identify the criteria and constraints of the problem, create a model, and then gather and analyze data to optimize their coin sorters. Teachers ask questions throughout this process to prompt students to reflect on their in-class experiences with the coin sorters and explore how those experiences might relate to what engineers really do. This explicit and reflective approach of planning representative activities and asking reflective questions demonstrably helps students deepen their understanding of the nature of science (Khishfe & Abd-El-Khalick, 2002), and we have found it applies equally to teaching NOE.


TETApr20VossFig1Day One: Constraints and Models

The teacher introduces the activity by telling students that they are part of a design team, and a bank has approached them to design a product to sort coins. The teacher then asks, “What questions do you have for the bank?” Students talk about this question in small (table) groups and then discuss their ideas as a class. Allowing students to talk in groups gives them time to generate more ideas of their own before the class discussion. During the class discussion, the teacher writes each of their questions on the board. Example student questions are listed in Table 1 below.


Once there is a list of 4-6 questions on the board, the teacher asks students, “How will the answers to these questions affect your work on the project?” and, “Why do you think engineers need to identify these types of questions before they start working on a project?” Students often discuss how knowing exactly what the bank wants in a coin sorter makes it easier for them to design something that will make the bank happy. They also talk about how materials and time influence (and often limit) what can be designed. The teacher then explains to students that engineers call these types of limits “constraints” and writes this new term on the board. To make sure that students understand this new term, the teacher asks, “What might happen if an engineer doesn’t understand the constraints of a project?” Students confirm their understanding by answering that engineers might not get something done in time, might make something the bank doesn’t want, or plan to make something for which they don’t actually have the materials. After this short NOE discussion, the teacher answers the student-generated questions on the board to the best of their ability (see Table 1 for example teacher answers).


TETApr20VossFig2Once students understand the expectations for the activity, they are asked to begin planning their designs in table groups of 2-3 students. The students are not given access to materials at this point. This is done to discourage students from using a hands-on, trial-and-error type approach that is not reflective of the work of engineers (NRC, 2009). While students discuss their plans, the teacher walks around the room and checks in with each table group.


If table groups are having a hard time generating ideas for their coin sorter, the teacher can show them a video (example: that demonstrates how fruit is sorted based on size. The teacher can then ask students to consider how they might use what they see in the video to help them with their coin task.


Most groups draw pictures to plan their coin sorters (Figures 1 and 2). While students are planning, the teacher stops the class and says, “I know you aren’t finished yet, but we notice a lot of groups are drawing pictures. Why is that helpful to you?” Or, if no groups are drawing pictures the teacher can ask, “Why might it be helpful for you to draw a picture?” Students generally recognize that the drawings help them communicate their ideas and visualize whether those ideas will work. The teacher then tells students that their drawings are a type of model (and write “model” on the whiteboard) and asks, “Why do you think real engineers use models?” Students speculate that real engineers use models for similar reasons and often recognize that it is easier for engineers to make changes to a model than to a final product.


Students may incorrectly assume that all drawings are models. To address this misconception, the teacher asks, “How is the model you drew different from other types of drawing you might do?” Students often say that they are drawing something they plan to create later. If students do not mention materials in their answers, the teacher asks, “How does your model show what materials you plan to use?” and “Why is it important for a model to reflect materials?” By the end of the discussion, students should understand that a model is made with the intention of communicating structure, materials, and how a design will function.


After the discussion of models, students can continue their work, this time with access to materials including cardboard, tape, glue, paper, scissors, and a variety of coins. The teacher continues to monitor the class by walking around the room and checking in with each group. At the end of the class period, students are asked to make sure their names are on their coin sorters and to store them safely for Day Two.


Day Two: Iterations and Collaboration

Day Two begins with the teacher asking students, “How have your ideas changed since you first started working on your coin sorter?” Students often mention that their ideas have changed because the model they drew on paper during Day One did not translate well to real life. If students do not come up with this idea, the teacher can scaffold them by asking, “How is your coin sorter different from the picture you drew yesterday?” The teacher then asks students to state specific reasons that their initial models needed changes. Student answers often include: materials were difficult to work with, coin sorter was not able to sort coins, coin sorter fell apart, and components needed to be resized. After a thorough discussion of changes, the teacher helps students transfer their thinking to the work of engineers by asking, “What might cause real engineers to change their designs?” Students recognize that, very generally, engineers change their designs to make them better. The teacher explains to students that these changes result in different versions of a design that engineers call “iterations.” This new term is written on the board.


Next the teacher begins a discussion of the collaborative nature of engineering by asking the students, “How has working in a team helped you?” and “How might engineers benefit from working in teams?” Students commonly answer that they (and engineers) come up with a greater variety of ideas and can get more done when they work in teams. The teacher expands on this idea by asking students, “Why do students in this class have different ideas?” They often answer that students have different experiences and knowledge. To help students recognize the impact of cultural differences, the teacher asks, “How might culture influence engineers’ experiences and knowledge?” Students say that culture influences what they think is important. To extend students’ thinking, the teacher then asks them, “Why would it be important for engineers to work with people who do not have the same culture and experiences?” and follows up with, “How does this help them come up with better designs?” Students answer that different perspectives and background knowledge can help engineers come up with better products or solutions that work for more people. As the discussion wraps up, the new term “collaboration” is added to the list on the board.


Students are asked to complete their coin sorters by the end of the day and are given the rest of the period to work. Refer to Figures 3 and 4 for examples of student work. The teacher continues to monitor the class by walking around the room and checking in with each group.


TETApr20VossFig34Day Three: Optimization, Trade-Offs, and Design Process

Class begins with a quick carousel activity. The teacher directs students to leave their coin sorter on their home group table and then rotate in groups to the other tables. This encourages students to consider the coin sorters that their classmates created. The teacher then asks students to compare their coin sorter designs. Students often note that some of the coin sorters operate differently, are made with different combinations of materials, or vary in size. The teacher then asks them, “How could you determine which design is the best?” Students brainstorm as a class and generate a list of methods on the board (Table 2). Together, the class decides on a method to collect data; students generally choose to see which design sorts coins the fastest. To make sure that students have a clear idea of how to collect this data, the teacher asks them, “How can we make sure each group is timing in the same way?” As a class, students decide when to begin and end timing (e.g., start timing when fingers let go of coin, stop timing when you hear the last coin drop) and what timing device to use (e.g., cell phone, stopwatch, clock). The teacher also asks, “Why might it be important for each group to use the same number of coins?” Students reply that they can’t compare times with other groups if they are each using a different number of coins. When the teacher is satisfied with a clear procedure, students are directed to work in groups to time their coin sorters and then record their results on the board for all to see. 


When all student groups have recorded their times on the board, the teacher asks the class, “Based on these results, which coin sorter is the best?” Students of course answer that the coin sorter with the fastest time is the best. The teacher then asks, “Even though this coin sorter had the fastest time, why might it not be the very best coin sorter?” Hopefully, students think back to the list of methods (Table 2), recognizing that multiple criterion are used to evaluate a design. The teacher then directs students to decide on a method to collect data on a different characteristic of the coin sorter (e.g., accuracy) and again has them test and record their results on the board. Students should test and collect data on 2-4 characteristics. 


When students have finished collecting data, the teacher asks them, “How could the data we collected help you make your coin sorter better?” Students generally answer that they could see where their coin sorter wasn’t very good based on the data and then work on making that part better. The teacher helps students connect this analysis task to the work of real engineers by asking, “How do you think real engineers use data to continually improve their designs?” Students respond that engineers use the data to identify what they need to improve. The teacher explains to students that engineers call this idea “optimization” and writes this new term on the board list.


The teacher then asks students, “How did you decide what changes were most important to make to your coin sorter?” Some students answer that it was more important to them to have a faster coin sorter, and others felt it was okay to have a coin sorter that was a little slower if it was easier to operate. The teacher asks students, “How do engineers decide what changes to make?” Students talk about how engineers judge designs by how well they meet the constraints and how well they work, but they also use their opinions. At some point students note that sometimes engineers must consider the good and the bad of their choices. The teacher tells students that these are called “trade-offs” and explains that engineers use data and their personal values to decide what is best (Norman, 1998).


The activity ends with a discussion of the NOE idea that a single design process may misrepresent the work of engineers (Kruse, et al., 2017; Pleasant & Olson, 2018). The teacher begins by asking students, “What things did you do to create your coin sorter?” Students typically describe their process using the following steps: create a model, build a coin sorter, collect data, make changes. To help students see that this process actually varied from group to group, the teacher says, “To what extent do you have to do these things in the same order?” Students begin to realize that they do not have to use the same step-by-step process to create a coin sorter. For example, some students made changes to their model after building their coin sorter because they were trying to communicate new ideas to members of their group. The teacher ends the class period by asking students, “Why is there no single design process that all engineers follow?” Students answer by explaining that engineers take different actions based on how and when their ideas change, or when they see things not working.



The teacher may assess students’ views of the NOE throughout the three-day activity by using any of the questions in Table 3. In this article the questions are used as discussion prompts, but they can also be used as exit slips, journal reflections, or quick-writes. For example, the teacher might ask students to complete an exit slip after Day One using the following question: “Why do you think real engineers use models?” Correct student responses may include that drawings/models help them communicate their ideas and visualize whether those ideas will work or not, as well as that it is easier for engineers to make changes to a model than to a final product. An incomplete response would be that the model is just a drawing of the design.


To assess NGSS standard MS-ETS1-4 in addition to NOE views, the teacher can have each group make a three-column chart at the conclusion of Day Three that lists (1) the changes they made to their designs (on Day Three), (2) why they made each change, and (3) how it affected their design (in both good and bad ways). See Table 4 for example student responses. Student explanations should specifically mention data collected. In addition, the teacher may ask students to reflect on the following NOE question: “How do engineers decide what changes to make to their designs?” Correct responses include the following: it makes it a better fit for the bank, or data from the model was used to improve the design.


We use a standards-based system in our classrooms. That is, rather than assigning points to students’ responses, we identify whether a student has met the standard. Rather than collecting points, students use the examples above to create a body of evidence that shows they have come to understand the NOE. Our job is to determine if the body of evidence meets the standard using a dichotomous (yes/no) approach.




As students come to understand the NOE, they will see that:

Creativity is inherent in the engineering design process. Optimism reflects a world view in which possibilities and opportunities can be found in every challenge and an understanding that every technology can be improved. Engineering is a “team sport;” collaboration leverages the perspectives, knowledge, and capabilities of team members to address a design challenge.” (NRC, 2009, p.152).

We hope a greater diversity of students will consider careers in engineering as they come to understand engineering and design to be creative, social processes that solve meaningful problems.



Kruse, J., Edgerly, H., Easter, J., & Wilcox, J. (2017). Myths about the nature of technology and engineering: Using the philosophy of technology and engineering to expose misconceptions. The Science Teacher, 84(5), 39.

Khishfe, R. & Abd-El-Khalick, F. (2002). Influence of explicit and reflective versus implicit inquiry-oriented instruction on sixth graders’ views of nature of science. Journal of Research in Science Teaching, 39(7), 551-578. 

National Academy of Engineering & National Research Council (2009). Engineering in K-12 education. National Academies Press.

NGSS Lead States (2013). Next generation science standards: For states, by states, (Appendix I). National Academies Press.

NGSS Lead States (2013). Next generation science standards: For states, by states, (Appendix F). National Academies Press.

Norman, E. (1998). The nature of technology for design. International Journal of Technology & Design Education, 8(1), 67-87.

Pleasants, J. & Olson, J. K. What is engineering? Elaborating the nature of engineering for K‐12 education. Science Education.


Sarah Voss is a graduate student in Science Education at Drake University in Des Moines, IA. She can be reached at

Hannah Klinker is a graduate student in the School of Education at Drake University in Des Moines, IA. She can be reached at

Jerrid Kruse is an associate professor of Science Education at Drake University in Des Moines, IA and can be contacted at


This is a refereed article.