The tools and techniques of science and engineering overlap in many ways, but there are some fundamental differences in how engineers use them versus how scientists do. One main distinction is purpose. In general, the goal of engineering is to solve problems, while the goal of science is to explain natural phenomena. The two practices that highlight this contrast are “Asking Questions (science) and Defining Problems (engineering)” and “Constructing Explanations (science) and Designing Solutions (engineering).” Other practices are used similarly by scientists and engineers, simply with a different purpose in mind.