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Doppler Effect
Mach was successful in producing the Doppler Effect in a lab experiment, as well as "demonstrating the correctness of Doppler's formula for the dependence of the sound-wave frequency on the movement of the source (Reichenbach, 1983)." This was the first time the Doppler Effect was able to be proven, since many others did not accept his explanation and discovery. -
Mach's Bands
Mach published an article discussing optical illusions, stating "the cause of this effect is due to contrast perception," which is over-processing at boundaries, and under-processing any consistencies. Before Mach, optical illusions were just seen as errors in judgement. He argued against this, saying that "perception works through perceiving the relations between stimuli (Pojman, 2019)." -
On Some Principal Questions of Physics
This essay argued that "matter is an abstraction of the same kind as the soul (Staley, 2013)." It went on to explain how he thought people experience an inner side of nature as well as an outer side, and providing advice that we need to measure ourselves in comparison to the standards of the outer world, and vice versa. He also went on to compare "an extension of gravity to all matter with Fechner's generalization of a soul inherent in all matter." -
Eisenbahn Phänomene (Railway Phenomena)
While on a train rounding a curve, Mach observed "trees and buildings along the side of the track angle outwards." He began studying how humans sense changes in rotation--leading to his discovery of how changing pressure of fluids in the inner ear canals was the cause of that sensation (Staley, 2013). This also allowed for the "distinction between angular acceleration and angular velocity." -
Swivel Chair Created
Mach built a chair that could be rotated on axes, and blocked visual cues to test how the subject sensed how they were rotating. He also discovered that if the subject "continued to rotate at a constant speed, the sensation gradually waned until they believed themselves stationary (Staley, 2013)." As the chair slowed rotating, the subject also believed to be rotating in the opposite direction. This chair is deemed the ancestor to modern astronaut training devices. -
The Science of Mechanics--Mach's Principle
This book challenged Newton's theory of absolute space, responding to the rotating bucket experiment conducted by Newton. Mach argued that "Newton’s experiment merely shows that the relative rotation of the water with respect to the sides of the vessel produces no noticeable centrifugal forces and that such forces are instead produced by its relative rotation with respect to Earth and the other celestial bodies (Staley, 2013). This also was a contribution in Einstein's theory of relativity. -
Analysis of the Sensations
Originating from the Gestalt Theory, Mach stated that "all knowledge is derived from the sensation; thus phenomena under scientific investigation can be understood only in terms of experiences, or 'sensations,' present in the observation of the phenomena (Britannica, 2022)." Mach also explained that sensations are the "interaction of experience with a pre-formed cognitive structure (Pojman, 2019)." This explains how we can hear a melody, and know what it is, regardless of how it's played. -
The Mach Number
Created the Mach number, as well as the principles of supersonics, or "the ratio of the velocity of an object to the velocity of sound (Britannica, 2022)." https://www.youtube.com/watch?v=VlaGxYjnoPY (KhanAcademy, 2010)