The authors of this article explain how two Veconlab class "experiments" can be used to clarify common points of confusion about the cost curves (sunk, marginal, and average). In each case, the experiment can be motivated, framed, or explained with environmental policy applications that are provided in the suggestions-for-discussion section. The connections to climate change are used to enhance student interest. Providing relative earnings information during the experiment is an effective way to let students discover their own misconceptions.