Movie explosions and special effects fascinate us on screens big and small. So what are we technically seeing on screen? These scenes are often deeply rooted in physics, careful science, and computer-generated algorithms.
There are two ways explosions release energy — by deflagration and detonation. The explosions that practical effects maker Steve Wolf usually creates are deflagrations, which produce pressure waves that are subsonic and are easier to control. The pressure waves of detonation explosions travel faster than the speed of sound, and are over so quickly that they are not ideal for action-packed movie scenes. Instead, Steve relies on fire reactions to create colorful, slower scenes that we have come to think of as explosions.
Filmmakers can also use computer-generated animations to produce cinematic explosions. Though these animations have been typically slow and costly to produce, Dr. Theodore Kim developed a new approach to make the process much more efficient. In his paper called Wavelet Turbulence, a new algorithm could produce detailed, realistic explosions in a shorter amount of time. It became a tool that was so popular for filmmakers that it was featured in numerous films, eventually earning Dr. Kim an Academy Award in 2013.