Images of an explosion can be used to study some of its physical properties. In this talk I will review the key aspects of the fluid dynamics of an explosion and how the solution of hydrodynamic equations confirm a classic dimensional-analysis method originally developed to study the first nuclear detonation. The main result is then applied to the images of the Trinity test to estimate the yield of the first nuclear test. An equivalent analysis is performed using images from social-media videos of the Beirut explosion of August 2020 to determine the energy of the explosion. The result will be compared to others using different methods.
Indiana University, USA.