Eötvös experiment
The Eötvös experiment is an experiment carried out by Loránd Eötvös and colleagues on gravity ( gravitation ), in which it was checked whether bodies made of different materials fall in different directions. It was not possible to measure different directions of fall for different objects.
The experiment
In the context of Newton's theory of gravity , the experiment is evaluated as a precise examination of the relationship between heavy mass and inertial mass in the relevant measurement objects. This assessment is based on the idea that bodies with a different ratio of inert and heavy mass could react differently to the earth's gravitational field . According to Newton's theory, the weight of a body on the earth's surface is determined by two fundamentally different forces - the gravitational force on the one hand and an inertial force resulting from the earth's own rotation , the centrifugal force , on the other.
At the place where the experiment was carried out, both forces do not point in the same direction. Therefore, different bodies that react differently to the two force components of gravity could fall in slightly different directions. It is also conceivable that they fall at different speeds. This possibility was not investigated in the Eötvös experiment; this was already done by Galileo Galilei and Isaac Newton and then by many other experimenters.
A long torsion pendulum is used for the experiment :
- Two bodies at the lower end of the pendulum experience a deflection in the direction of the earth's equator due to the centrifugal force acting on the earth's rotation ; the deflection force is proportional to the inertial mass .
- The force of gravity counteracts the deflection; this is proportional to the heavy mass .
- The measured deflection agrees with the calculated one if identical values are used in the calculations for inertial mass and heavy mass .
Since the examined bodies remain at rest in the laboratory system, no dynamic variables were measured, only the deflection angles. It could be shown with a precision of 1:10 8 that the ratio of heavy and inert mass is the same for all examined bodies. This accuracy could later be improved by more than three orders of magnitude.
Loránd Eötvös first carried out this experiment in 1889 and published its results in 1890. Together with Pekár and Fekete, he refined the measurements between 1906 and 1909.
The precision methods used here are today u. A. used in applied geophysics and reservoir research (see gravimetry ).
The equivalence of inert and heavy mass, which was initially determined purely empirically, has become of fundamental importance by pointing to a close relationship between gravitation and inertial forces: Albert Einstein made this as the equivalence principle the basis of his general theory of relativity .
A modern version of the Eötvös experiment is the molybdenum disk experiment (Eöt wash experiment).
See also
literature
Dieter Meschede: Gerthsen Physics . Springer DE, November 4, 2010, ISBN 978-3-642-12893-6 , p. 47f (accessed on January 28, 2013).
Individual evidence
- ^ Klaus Dransfeld , Paul Kienle , Georg Michael Kalvius : Mechanics and Warmth . Oldenbourg Verlag, 2005, ISBN 978-3-486-57810-2 , pp. 94f (accessed on January 28, 2013).
- ↑ Roland Baron Eötvös: About the attraction of the earth to various substances. In: Mathematical and scientific reports from Hungary. Eighth volume, 1889–1890. Berlin, Budapest 1891, pp. 65–68, 1890. ( digitized version of the publication )