Experimental studies have demonstrated that even highly educated people do not understand stock-and-flow dynamics. Such misperceptions are currently having potentially disastrous effects in the area of climate change policy, where very few non-technical experts yet grasp that stabilizing carbon in the atmosphere will take a massive (50-80%) reduction in emissions in the coming decades. In order to correct such misunderstandings and to support a more grounded public discourse on the speed and scale of response needed to the threat of climate change, a diverse team has constructed an interactive, online simulator for the general public that includes an animated bathtub, so that the learner may experiment with different policy approaches to stabilize atmospheric carbon dioxide. Although extremely simple, the aim of fostering broad, intuitive public understanding has been neglected by more complex climate change models. This presentation will briefly demo the "Sim" and explore the learning theory that undergirds it and the planed series of "freeware" climate simulators.