Explore the impacts of nanoscale energetics on geochemistry, the environment, and materials science in this 44-minute keynote presentation from the 2015 MRS Spring Meeting's Symposium X series. Delve into calorimetric techniques that reveal how surface energy differences among various phases lead to significant changes in thermodynamic stability. Discover how these changes affect geochemical and biogeochemical processes, heavy metal transport in the environment, catalysis, and energy application materials optimization. Examine case studies on iron and manganese oxides, lithium battery cathode materials, and cluster compounds ranging from aluminum to uranium. Learn about surface entropy, oxidation state effects, and interfacial energies. Gain insights into current issues, major challenges, and future directions in this field of research.