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Mach Bands
In 1865, Ernst Mach discovered an optical illusion in sensory psychology. When one color of different shades touches, they make a line or band of a darker color to distinguish between the color blocks. This is the optical illusion of a Mach Band and works by triggering an edge-detection function in the optical tract. This has been found very important and useful in radiology between bone density in dentistry and many other fields. -
Equilibrium
In 1873 Ernst Mach discovered how the human body senses balance and head position by measuring brain activity when fluid in the semicircular canals of the ear flowed each way. He and another scientist (Breuer) are credited for discovering this non-acoustic function of the ears. Mach tested his theory using a swivel chair to see how the structure in the ear actually functions, and previous functional information on semi-circular canal structure was discovered by Goltz in 1870. -
Wave Measurements
From 1974-1893 Mach developed new optical techniques to observe sound and light waves along with their propagated spread. He did not discover the waves themselves, but methods in which we can visually observe them. His techniques were used to observe the waves of the sound barrier and led to his discovery and creation of the Mach number. He used a schlierenmethode to photograph the invisible waves to see how the waves themselves function and affect. -
The Mach Number
In 1887, Ernst Mach discovered the Mach number, which is named after him. The Mach number is the ratio of an object's velocity and the speed of sound. Mach was the first person to systematically study super-sonic motion and came up with a nondimensional measurement of speed. When an object hits Mach 1, they are at the speed of sound and was discovered by Mach and Peter Salcher who took a photo of the shock wave when the sound barrier was broken, effectively inventing the Mach Number.