Explanations of the spontaneous assembly of molecules into mesoscopic (nanometric) or micron-sized structures that are important in biological cells (i.e. membranes, polymers, and colloids), require an understanding of cooperative behavior in interacting, multi-particle systems. We present a conceptual and quantitative framework for teaching these phenomena to introductory-level students, which was tested in a pilot interdisciplinary course given to advanced (AP level) high school students in Israel. We first discuss the competition of configurational entropy (that leads to randomness) and interparticle interactions (that leads to structure formation) in terms of a lattice model in the context of binary mixtures. The lattice model, which allows for simple calculation of both entropy and interactions also provides a concrete visualization of the particles comprising the system; it is used in the statistical thermodynamics via free energy minimization. Our approach is then used to model the mesoscale structure and macroscopic phase separation of fluid mixtures and the resulting interfaces, polymer solutions, and the self-assembly of lipids1. Parts of the curriculum can be incorporated into restructured introductory physics courses for life sciences, allowing students to understand how the competition between interactions and entropy is resolved in the formation of mesoscopic structures. The course is also beneficial for physics and chemistry students since it provides them with insight and quantitative examples of strongly interacting, many-particle systems; this is in contrast to the one-particle systems that are typically the focus of introductory physics courses. The syllabus can also form part of an integrated, quantitative science course which can be presented at the introductory level since it does not require advanced mechanics, electromagnetism or quantum mechanics.1 E. Langbeheim, S. Livne, S. A. Safran, E. Yerushalmi, Introductory physics going soft.American Journal of Physics, 80, pp. 51-60, 2012.