STEM is a way to organize and deliver instruction; it is not a specific content area (Vasquez et al. 2013). Allowing students to use the engineering cycle, to fail and improve, to receive critiques and revise, are all tenets in STEM education. They are also part of the learning process for all humans. By definition, STEM teaching is good teaching that allows for revision, feedback, and reflection. As we think about interdisciplinary work, we can consider different levels of integration across disciplines: First, multidisciplinary lessons address a theme in each silo classroom. Second, interdisciplinary units cover a project that students take with them to two or more classrooms. Third, transdisciplinary learning happens when all the skills are required to do the learning, and there are no wall or time barriers (Vasquez et all 2013). STEM is already an integration of content and practice, and the act of learning is a holistic one (Hoffer 2016). The ability of STEM to draw from all aspects of learning makes the experience powerful and memorable while students use metacognitive skills to construct learning.
Project-Based learning is a transdisciplinary practice, where students pull from all subjects and processes to develop a solution to their problem. As Selmer et al. (2014) describe, they used PBL to encourage statistical literacy using math and science. The students used statistics to inform what they should plant in a classroom garden, how their sales were going at the farmers market, and then after their project to determine future directions. As Larmer, Mergendoller, & Boss (2015) point out, an essential project design element is a challenging problem or question: this question must be authentic and answered using many different skills and sources of information. Teachers still need support in developing interdisciplinary PBLs: Krajcik et al. (2008) show that developing learning performance tasks connects the content standard and the practice. This allows students to integrate content and practice and allows teachers to package the process skills and the content from state/national standards. Johns &Mentzner (2016) Point out that integrating science and engineering can expose students to the essence of scientific inquiry. They analyzed student engagement and process using a lunar plant growth chamber NASA lesson and incorporated the optional design elements. In the Companion to STEM project learning, Capraro et al. (2016) present 25 PBL lessons, and they all include standards in Science, Language arts, Technology, and Math. These standards are taught through lessons that cover technology, mixtures, nutrition, construction and design, water, and the environment. All these topics require integration of many skills to solve authentic problems, communicate results, collaborate, and succeed.