Achieve, Inc., with the assistance of the National Research Council (NRC) and the National Science Teachers Association, released K–12 engineering standards as part of the Next Generation Science Standards (NGSS Lead States, 2013). With the release of the NGSS, elementary science teachers are now required to integrate engineering into their teaching. The NGSS challenge teachers to guide elementary students’ inherent ability to design and build toward meaningful problem solving with the engineering design process (EDP; NGSS Lead States, 2013).

Taking Science to School (NRC, 2007) underlined that elementary students come to school with prior experience and understanding of science and engineering. Although lacking the core knowledge and skills, elementary students have the capacity to learn engineering with necessary scaffolding. Dewey underscored the importance of personal interest and prior conceptions in students’ career choices (Dewey, 1913). Meaningful and relevant topics ignite students’ natural interest (Cook, Bush, & Cox, 2015). Thus, a well-designed engineering curriculum may spark student interest in an engineering field.

Elementary students are natural designers and builders. They construct toys for playing and use novel apparatus and design structures in their games (Cunningham & Hester, 2007; NRC, 2012; NGSS Lead States, 2013). Their creativity inspires unique engineering designs with limited materials. The NGSS challenge teachers to guide this natural talent toward meaningful problem solving with the EDP. In elementary classrooms, the EDP can be introduced as: (a) defining the problem, (b) designing solutions, and (c) optimizing design solutions (NGSS Lead States, 2013). In upper elementary grades, teachers can introduce predetermined criteria and constraints for an engineering design solution as part of an engineering design challenge to make the engineering design experience more realistic (NGSS Lead States, 2013; NRC, 2012). Introducing the EDP in early elementary grades may spark all students’ interest in engineering careers. However, there are two obstacles preventing elementary students from developing an interest in engineering. First, the instructional time devoted to engineering in elementary school curriculum is limited. Engineering subjects have been neglected or minimized for the sake of standardized tests such as English language arts and math (Bull, Knezek, & Gibson, 2009; Deniz, Yesilyurt, & Kaya, 2017). Second, even if elementary teachers are given more time to teach engineering, they may not be inclined to teach it because they lack confidence and appropriate pedagogical content knowledge (Deniz, Yesilyurt, & Kaya, 2017; Kazempour, 2014; Quinn & Bell, 2013). Besides, elementary teachers may think that integrating engineering into their teaching requires extra effort that complicates their already busy schedules (Cunningham & Hester, 2007; NGSS Lead States, 2013).

Without proper professional development it can be hard for instructors to see how engineering is related to science and that other core subjects can be easily integrated into engineering (Deniz, Kaya, & Yesilyurt, 2018; Deniz, Yesilyurt, & Kaya, 2017; Berry et al., 2010). Stakeholders, educators, and policy makers need to provide training for elementary teachers to address obstacles in meeting the high demand for engineering instruction in elementary schools (Berry et al., 2010). In addition to lack of time and training, teachers also face the problem of limited resources available to assist them to integrate engineering into their existing curricula.

In-service teachers may have the challenge of weaving engineering into their instruction, but they have the advantage of teaching experience to guide that integration. Preservice elementary science teachers (PST) lack in-depth engineering knowledge and have limited confidence in teaching engineering (Deniz, Kaya, & Yesilyurt, 2018; Deniz, Yesilyurt, & Kaya, 2017). This deficiency may cause PST to be wary of engineering content and devote minimal time to engineering instruction or neglect teaching engineering altogether (Avery & Meyer, 2012).

Bandura (1997) defined self-efficacy beliefs as “belief in one’s capabilities to organize and execute the courses of action required to produce given attainment” (p. 3). Students’ self-efficacy beliefs about science can influence their perceptions of science and their achievement in science courses (Britner & Pajares, 2006). Having few opportunities to experience science and engineering at school can affect students’ STEM (science, technology, engineering, and mathematics) career choices. Elementary teachers’ low science and engineering teaching efficacy beliefs (Deniz, Kaya, & Yesilyurt, 2018; Deniz, Yesilyurt, & Kaya, 2017) can exacerbate the career choice problem. Elementary teachers with low science and engineering teaching efficacy beliefs can intentionally prioritize other subjects at the expense of science and engineering. Therefore, elementary teacher education programs need to modify their science teaching methods courses to provide pedagogical content knowledge about teaching engineering.

Elementary teachers generally feel confident in teaching language arts and math (Deniz, Kaya, & Yesilyurt, 2018; Deniz, Yesilyurt, & Kaya, 2017); however, they have a weak knowledge of science, let alone engineering (Yasar et al., 2006). For that reason, successfully designed elementary science teaching methods courses are needed to improve PST content knowledge (Bull, Knezek, & Gibson, 2009) and efficacy beliefs before they enter the classroom. Bandura (1977) identified two constructs for self-efficacy beliefs: (a) outcome expectancy and (b) personal teaching efficacy. In terms of teaching beliefs, outcome expectancy is related to a teacher’s beliefs about results of his or her teaching. Personal teaching efficacy is about a teacher’s confidence in his or her capability to teach the particular concept. To measure teachers’ self-efficacy beliefs, Enochs and Riggs (1990) developed the Science Teaching Efficacy Belief Instrument (STEBI; Bleicher, 2004; Boone, Townsend & Staver, 2011). STEBI was designed to measure two categories of self-efficacy: (a) personal science teaching efficacy (PSTE) and (b) science teaching outcome expectancy (STOE). Because studies have shown a positive correlation between self-efficacy and teachers’ pedagogical knowledge and experience (McLaughlin, 2015), we aimed at increasing PST self-efficacy beliefs by introducing engineering with 3D modeling and printing in our elementary science teaching methods course.

In this study, we describe a novel way to introduce EDP to PST by integrating 3D printing experience within an engineering design challenge. We hypothesized that integrating EDP in a science teaching methods course would improve PST engineering teaching efficacy beliefs. The purpose of this article is twofold: (a) to provide a detailed overview of 3D printing instruction and (b) to determine to what extent PST engineering teaching efficacy beliefs change after participating in an engineering design challenge including 3D printing.

We measured 20 PST engineering teaching efficacy beliefs at the beginning and at the end of an elementary science teaching methods course offered in a southwestern higher education institute. All PST are required to take introduction to physics, chemistry, and biology courses prior to taking the science teaching methods course, but engineering instruction has never been introduced before. Eighteen of the PST were female and two PST were male. Fifteen of the PST were Caucasian, five were of Hispanic origin, and all were senior grade practicum PST.

We embedded 3D printing in the EDP in our elementary science teaching methods course. We engaged PST in 3D design and printing to introduce EDP to PST: define the problem, develop solutions, and optimize design solutions.

1. Defining the problem involved understanding the criteria and constraints of the engineering challenge (described in the Intervention section), but also the features of the 3D printer and TinkerCAD. When the PST understood the given challenge, they could begin developing solutions.
2. The 3D printer used in an engineering context starts by designing a prototype. Possible solutions were developed in teams, discussed as a class, and modeled with the software. To promote scale and modeling, TinkerCAD 3D modeling software was used because Computer Aided Drafting (CAD) software is common in most engineering disciplines.
3. Once the design was completed, the PST tested, revised, modified, and improved their 3D models.

This approach allowed us to integrate the NGSS elementary EDP with 3D printing so that we could demonstrate how to teach engineering at the elementary level. Specific details of the implementation follow.

Our intervention was included in one section of an undergraduate-level science teaching methods course designed for PST. The course met for 2.45 hours each week during the 15-week 2017 spring semester. The purpose of the course was to prepare PST to teach elementary science effectively in their future classrooms by providing them with the necessary knowledge and skills. To accomplish this, the course included topics such as using science notebooks, nature of science, eliciting students’ conceptions about science topics, concept mapping, the NGSS, teaching science through inquiry, 5E learning cycle lesson planning, integrating science with other subjects, technology applications in elementary science teaching, assessment, and engineering design process. The unit was created collaboratively by the authors that consist of an engineer, a STEM teacher, an engineering education researcher, and a science education faculty. The instructor was a former professional engineer, who has a K–16 STEM+CS teaching experience and engineering education research background. The instructor’s background in engineering and education supported the formation of the 3D printing EDP unit through project-based learning.

This 3D printing engineering design project addressed the close relationship between engineering and technology. PST experienced the EDP by engaging in 3D design and printing with TinkerCAD. We devoted 2 weeks to 3D design and printing. The 3D printing instruction involved learning specialized designing techniques (e.g., spatial visualization), group discussions, and engineering notebook reflections. PST mainly worked in groups of two during the course, including the 3D design challenge.

The intervention started with a 20-minute introduction to the history and evolution of 3D printing, working mechanism of 3D printers, and displaying examples of 3D printed objects. Then a scenario was introduced in which PST were asked to design a keychain for a person who frequently lost his/her keys. The person wanted a keychain that was small enough to fit in a person’s pocket with a distinctive shape.

We provided PST with criteria and constraints (ease of use, design viability, physical appearance, size, originality, and creativity) that they needed to consider while designing their keychains. The PST worked in groups to 3D design and print a keychain by following NGSS EDP. This scenario provided our PST genuine experiences in the designing and optimizing solutions phases of the EDP. In the designing solutions phase, PST were planning, sketching models, and communicating. Optimizing included improving the designs by comparing them with other graphical models in TinkerCAD. The PST completed additional testing and revising of the model to meet the criteria and constraints. When PST completed the first draft of their sketches, they showed their designs to the team members and received feedback about how to improve the design according to the scoring rubric (see Appendix). PST evaluated their keychain designs by evaluating their scoring rubric and decided on the final prototype on the basis of the received scores. They improved their designs and shared the 3D model with the instructor. Because the last two phases were on the computer, they could be completed iteratively and easily shared with other groups. When the instructor confirmed the design, they downloaded the file in .STL format, sent it to the Makerbot desktop software, and their design was printed. The instructor let the PST remove their designs from the building plate as a firsthand experience. He also shared the resources and best practices about how to effectively use and troubleshoot 3D printers. He consistently reminded PST that failure is part of the EDP and manufacturing. Iterative design is the key to successful 3D designed products.

Even though PST had no prior experience with this novel technology, they were able to design keychains and print them. We observed the following challenges with designing 3D objects in TinkerCAD environment and the actual 3D printing during our intervention:

• initial training required to use TinkerCAD and practice required to be proficient,
• difficulty in navigating the camera angles in TinkerCAD,
• challenges in working with touchpad in TinkerCAD medium,
• navigation challenges in 3D spatial environment,
• Snapping and aligning issues with the shapes,
• starting the design with basic shapes limits the creativity while providing simplicity,
• slow printing time,
• and difficult to remove small printed objects from the build plate.

PST were also given time to explore Thingiverse Education, an online platform where teachers share lesson plans that integrate 3D printing in a broad range of subjects, where best practices are shared, and where troubleshooting strategies are provided. We also informed PST about customization of existing designs and how to remix them with the Thingiverse Customizer. With the Customizer, 3D printing enthusiasts can manipulate and modify the designs according to their needs.

Furthermore, the instructor, who has been successful in applying for a variety of grants (e.g., Donorschoose, Honda Foundation, and IEEE Foundation) took time to inform the PST about the approximate cost of 3D printers and grant opportunities available to make 3D printing a realistic possibility for the teachers. He provided information on cost-effective, teacher-friendly educational 3D printers available on the market that range between $300 to $1,000.

We used Makerbot Replicator + 3D printer with TinkerCAD modeling software during this project. This 3D printer can print objects around the size of a shoebox. The 3D printer melts the filament to the required temperature and feeds it through a nozzle by its smart extruder (Martinez & Stager, 2013). We used Poly Lactic Acid (PLA) filament that has been recommended to educators because of its safety; PLA filament does not need ventilation and leaves a nice smell, like waffles, as it is made of organic plants, especially corn starch (Goodrich, 2013; Makerbot, 2015). The head of the printer moves in the × and Y directions horizontally, and the print bed moves up and down in the Z direction vertically; this allows it to cover the 3D space (Makerbot, 2015; Mersand, 2015). 3D printing is an additive manufacturing process, starting from scratch and then depositing thermoplastic filament layer by layer until the product is finished (Szulżyk-Cieplak, Duda, & Sidor, 2014). The movement of the motors are controlled by the onboard processor of the 3D printer. That built-in processor communicates with the desktop 3D software to guide the process. This software slices the 3D modeled design and converts it into the language of the printer that can communicate with the computer (Junk, & Matt, 2015; Makerbot, 2015; Satyanarayana, & Prakash, 2015).

Using the correct software is one of the important steps in sparking interest in 3D printing in elementary engineering education. TinkerCAD, a free, elementary friendly, online drafting site by Autodesk can be easily integrated into the elementary engineering curriculum (Buhler, Gonzalez, Bennett, & Winick, 2015; Makerbot, 2015). It offeres easy-to-model sketches by dragging 3D shapes into the work plane, which looks like grid paper. Students can start with a shape like a triangle or square. They can combine and group different shapes. They can modify the shapes by pushing and pulling, and they can create holes using their mouse. Later they can change the size and position of the object (Makerbot, 2015). One of the strong features of TinkerCAD is its cloud-based platform, which does not require software download and installation. TinkerCAD can be integrated with a student management system called Project Ignite that allows teachers to assign lessons and keep track of their students’ progress in the TinkerCAD platform. Project Ignite provides the tools to support teachers to teach 3D design effectively by providing opportunities such as creating tutorials and lesson plans.

In TinkerCAD, when users are finished with modeling, they can download their design as a Stereolithography file format (.STL), upload the file into the Makerbot Desktop app, resize and relocate it if necessary, and finally press the print button. Makerbot Desktop is a specialized slicing software that makes the file ready for 3D printing. It is a free application by Makerbot industries. The interface of Makerbot Desktop is similar to the build plate of the printer so users can visualize the size and the appearance of the model. Makerbot Desktop’s customization tools allow users to modify the resolution of the model, adjust the filament quantity of the object without sacrificing surface quality, and see the printing process duration. When the 3D printing is finished, users can remove the object from the removable build plate, peel the supporting materials with plastic spatula, and polish and smooth the surface with sandpaper (Makerbot, 2015).

We analyzed the pre- and posttest scores of 20 of the total 22 PST with the Engineering Teaching Efficacy Beliefs Instrument (ETEBI). Because of incomplete responses, two students were omitted from the data analysis. We modified the Science Teaching Efficacy Beliefs Instrument Version B (STEBI-B; Enoch and Riggs, 1990) to measure PST engineering teaching efficacy beliefs by replacing “science” with “engineering.” The ETEBI consisted of 23 items, each to be rated by the participant on a 1 (strongly disagree) to 5 (strongly agree) Likert scale, and it also consisted of reverse-coded questions to assess validity. ETEBI probed these two subscales: (a) Personal Engineering Teaching Efficacy (PETE), which can be explained as confidence in teachers’ potential to instruct engineering content to the students, and (b) Engineering Teaching Outcome Expectancy (ETOE), which measures teachers’ perspective that effective engineering teaching positively influences student learning.

We evaluated the factor structure of the adapted STEBI instrument in another study (Yesilyurt, Deniz, & Kaya, 2019). Our exploratory factor analysis yielded two factors (PETE and ETOE). These two factors are analogous to original STEBI factors (PSTE and STOE). We reached sufficiently high reliability for both subscales. We found that the alpha coefficient of internal consistency of the PETE subscale was .92, and the ETOE subscale coefficient was .88.

To address our purpose, we analyzed the data in SPSS 25.0 Mac version. We investigated the influence of engineering instruction with 3D printing by analyzing two paired samples t-tests scores for pre- and posttest results. We provided the subscales results for PETE and ETOE (see Table 1). The two-tailed t-test results for PETE is p <.05 (t =—2.955, M =—2.80), whereas the two-tailed t-test results for ETOE is p <.174 (t =—1.414, M =—1.6). We also provided the means for each question in preassessment and postassessment and summarized our results in Table 2.

PST PETE scores increased significantly between preassessment (M = 49.85, SD = 5.23) and postassessment (M = 52.65, SD = 5.13), t =—2.955, p < .001. The PETE question, “I know the steps necessary to teach engineering design concepts effectively,” improved most compared with other questions from pre- to postassessment. On the other hand, whereas ETOE scores showed improvement, no significant difference was found between preassessment (M = 33.20, SD = 5.52) and postassessment (M = 34.80, SD = 4.53), t =—1.414, p < .174. Our data findings suggest that PST exposure to engineering instruction in a meaningful context as part of elementary science teaching methods course showed a significant increase in PST engineering teaching efficacy beliefs overall.

PST also reflected in engineering notebooks that 3D printing helped them to understand the EDP. However, we did not use the engineering notebooks as an evidence to assess the change in PST understanding of EDP knowledge. They found it an engaging activity that improved their understanding of engineering and technology. PST also reported that 3D sketching with TinkerCAD and 3D printing the design was an effective way to introduce the EDP for elementary students.

The aim of this study was to improve PST pedagogical content knowledge and show strategies for integrating 3D printing technology in NGSS-aligned engineering education. In this research, the 3D printing experience provided PST with the opportunity to improve their practices (knowledge and skills) in applying the EDP. ETEBI pre- and postassessments demonstrated that 3D printing with the EDP improved PST engineering teaching efficacy beliefs. Furthermore, PST reflected that introduction to engineering with 3D printers positively influenced their confidence to integrate engineering into their instructional practices. Our data suggest that a well-developed engineering instruction has a potential to help PST understanding of engineering content as well as improving PST engineering teaching self-efficacy beliefs. As a result, we think that when teachers have confidence in their engineering teaching efficacy beliefs they will easily engage elementary students in engineering design challenges and work toward increasing student achievement.

These positive outcomes encourage further research with higher sample sizes in engineering education, because our findings are similar to earlier studies focused on improving elementary teachers’ engineering self-efficacy beliefs, including a professional development component (e.g., Deniz, Yesilyurt, & Kaya, 2017). We found that inservice elementary teachers improved their PETE beliefs after a weeklong professional development program organized around a real-life engineering design challenge with an explicit focus on teaching the engineering design process. It looks like both inservice and preservice teachers need to specifically teach the engineering design in their own classrooms before they feel more confident about their ETOE beliefs. We plan to investigate the impact of teaching engineering design on ETOE beliefs of preservice and inservice elementary teachers. We think that engineering teacher educators can benefit from this study in designing science teaching methods courses for preservice teachers and professional development programs for in-service teachers in an NGSS era where engineering is an integral part of modern science education.

Acknowledgments

This 2-week-long (6 hours) Integrated Engineering With 3D Printing elementary science teaching methods unit was possible with the assistance of the Office of the Provost’s Start-up Scholarship of Teaching and Learning mini grant. 

Hasan Deniz (hasan.deniz@unlv.edu, hdeniz@gmail.com) is an associate professor, Erdogan Kaya is a PhD candidate and graduate assistant, and Ezgi Yesilyurt is a graduate assistant, all in the Department of Teaching and Learning at University of Nevada, Las Vegas. Anna Newley is a teacher at the Sonoran Science Academy in Phoenix, Arizona.