At the end of 2022, there were 2439 coal-fired power plants operating around the world, and over 7000 active coal mines (Global Energy Monitor, 2022). Coal burning was the largest source of greenhouse gases that impact climate change, and coal mining caused extensive environmental damage (US Energy and Information Administration, 2022). Decisions about the use of coal in energy production are made by world leaders, but everyday citizens vote for and appoint those leaders. Do everyday citizens understand the most basic science about coal? Do the teachers who are supposed to educate them in their youth? Energy literacy is so important; it leads to informed decisions about energy use at home, wise consumer choices, and to national and international energy policies (DeWaters & Powers, 2011). In this study, 56 pre-service elementary teachers were asked if they understood how coal was used to produce electricity. They were then taught using a constructivist teaching methodology including manipulatives, diagrams, videos, and group discussions (Schnittka, 2017). After the lesson, they were asked again, “How does coal keep the lights on?” Pre-test scores were very low, but gains were strong from pre to post-test. In a delayed post-test, the participants who retained the concepts the best over time had discussed it with a friend or relative. For long-term retention and the ability to potentially apply a concept to everyday life, teachers must realize that learning gains can be ethereal, and that they need to build in tools to aid in long-term retention of concepts. More importantly, teachers need to understand the science and engineering behind the technologies that impact our world so severely, so that they can pass on lessons to youth and advocate for a sustainable future.