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Professorship Affords Time To Study Shockwaves
Appointed Professor of Physics at the Charles University in Prague. He continued his studies and developed a method called a shadowgraph to take pictures of shockwaves. When high speed projectiles travel through a medium (like air), they cause the medium to heat up. The temperature difference causes light to bend. A bright flash aimed at flowing air as a projectile flows through it can capture the shock waves through the light bending through them. -
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Additional studies
During his tenure, he wrote over 100 papers. His work also included how the inner ear was related to balance, how inertia was an intrinsic part of matter and how the eye interprets visual stimulus. He initially was a disbeliever of atoms but eventually came around as experimental data grew confirming them. -
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Process Refinement
During the next decade or so, Mach further developed photographic techniques. What began as shadowgraphs evolved into schlieren photography, which is still used today. His studies helped him realize a relationship between the speed of an object and the speed of sound through the same medium. This relationship was later called the Mach number, named in his honor. The Mach number is determined by dividing the object's speed by the speed of sound. -
Presentation of supersonic ballistic shock wave
Mach presented his paper "Photographische Fixierung der durch Projektile in der Luft eingeleiten Vorgange" to the Academy of Sciences in Vienna. It included a photograph of the shockwave of a fired bullet as it moved through the air. He presented along with the photographer and colleague Peter Salcher. -
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Final years
Mach officially retired in 1901. A video showing modern applications of his schlieren photography can be found at: https://www.youtube.com/watch?v=BPwdlEgLn5Q
Bibliography
Mach, Ernst. The Principles of Physical Optics. New York, Dover, 1953. CDS.CERN, http://cds.cern.ch/record/107890?ln=en.
Mach, Ernst. The Science of Mechanics. Cambridge University Press, 2014. Cambridge.org, https://www.cambridge.org/core/books/science-of-mechanics/D8A72D6443150FDB4820DCA339836EB2.
