The SUN approach to biological energy transfer education is fundamentally different from past practices that trace chemical and energy inputs and outputs. The SUN approach uses a hydrogen fuel cell to convince learners that electrons can move from one substance to another based on differential attraction. With a hydrogen fuel cell, learners can see a propeller turning when only hydrogen and oxygen gases are present. The movement of electrons from the hydrogen fuel to the oxygen acceptor is supported with an animation of the invisible electron transfer and resultant products made. Living things run on microscopic fuel cells called mitochondria where the electron donor is food and the ultimate acceptor is oxygen. The SUN Project scaffolds understanding of this process with physical and digital manipulatives. Students configure nested trays with movable components so as to enact the salient processes that transfer matter and energy in the mitochondrion. Energy is harvested not in the turning of propellers, but in the eventual rotation of a nanomachine that produces a chemical essential for life called ATP. SUN scaffolds include a mechanically manipulated replica with supporting animations. Food making in chloroplasts depends upon light to initiate electron movement. The materials show that many of the intervening processes mimic those in the mitochondrion. The purpose of this cluster, randomized controlled trial (RCT) was to determine the long-term efficacy of the SUN Project intervention on student understanding regarding why and how CR and PS occur. Students participated in regular biology classes within schools randomly assigned to either the treatment (T) or control (C) condition. At the same time the achievement of a small group of AP biology students who did not use the SUN materials provided another meaningful context for interpreting outcomes. The research questions (RQ) of this project asked during the first year were: (1) Does the SUN Project significantly impact long-term student learning; (2) Does the SUN Project significantly impact student confidence in their understanding; (3) What variables moderate student outcomes; (4) How much do SUN vs. Control students value their instructional materials; and (5) How do the outcomes of treatment students compare to that of a small group of AP biology students who are not using the SUN materials? Tables and figures are appended.