In this session, we will discuss the central tenants of the 'Flat Earth Theory' and the elements thereof which, to a naive observer, appear to be consistent with observations. We will then discuss how additional observations can be used to debunk this theory, and how to avoid falling prey to simple, attractive, and yet wrong theories like the 'Flat Earth'. The goal of the session is to build scientific reasoning in students, and give them the tools to critically consider scientific theories. The session will be not be a lecture but will be highly interactive, focusing on allowing students to think about and counter several 'Flat Earth' talking points on their own.