The 2014 study, "Conceptualizing Astronomical Scale: Virtual Simulations on Handheld Tablet Computers Reverse Misconceptions," examined the effects of using the true-to-scale (TTS) display mode versus the orrery display mode in the iPad's Solar Walk software application on students' knowledge of the Earth's place in the solar system. The Solar Walk application is intended to help students understand the order of planets and their orbits. The TTS display mode shows planets in accurate scale, while the orrery display mode exaggerates the sizes of planets relative to their orbits. The orrery display mode is similar to traditional drawings in textbooks, where the solar system is not presented to scale. Study authors assessed the effectiveness of the TTS display mode versus the orrery display mode by randomly assigning students to use the TTS display mode or the orrery display mode on the first day of implementation. On the second day of implementation, the conditions were reversed. The study compared student performance on a 10-minute multiple-choice science test administered immediately after students completed the Solar Walk activities each day. The study is a well-executed randomized controlled trial that meets WWC standards for the comparison of students who used the TTS display mode to students who used the orrery display mode after the first day of implementation. While WWC calculations indicate no statistically significant effects of TTS on student outcomes, the magnitude of the average effect was large enough to be characterized as a substantively important positive effect. The comparison of students after the second day of implementation does not meet WWC evidence standards because all students had used both display modes. The following are appended: (1) Study details; and (2) Outcome measures for the science achievement domain. [The following study is the focus of this "Single Study Review": Schneps, M. H., Ruel, J., Sonnert, G., Dussault, M., Griffin, M., & Sadler, P. M. (2014). "Conceptualizing astronomical scale: Virtual simulations on handheld tablet computers reverse misconceptions." "Computers & Education," 70, 269-280. For "What Works Clearinghouse Quick Review: "Conceptualizing Astronomical Scale: Virtual Simulations on Handheld Tablet Computers Reverse Misconceptions," see ED544753.