Pendelgravimeter

A pendelgravimeter is a type of gravimeter that measures the acceleration due to gravity by observing the period of oscillation of a pendulum. The fundamental principle relies on the relationship between the period of a simple pendulum and the local acceleration due to gravity. For a simple pendulum of length L, the period T is given by the formula T = 2π√(L/g), where g is the acceleration due to gravity. By precisely measuring the period of a pendulum with a known length, the value of g can be determined.

Modern pendelgravimeters often employ a compound pendulum rather than a simple mathematical pendulum for practical reasons. These instruments are designed to be highly precise, with sophisticated mechanisms for suspending the pendulum and for measuring its period. Techniques such as optical interferometry are used to accurately track the pendulum's motion. The sensitivity of a pendelgravimeter allows it to detect very small variations in gravity, which are important for geological surveys, geophysical exploration, and studies of mass distribution within the Earth.

Environmental factors such as temperature and air pressure can significantly affect the period of oscillation, so pendelgravimeters are equipped with control systems to minimize these influences. They are typically housed in stable environments and undergo careful calibration. While less common than modern absolute gravimeters in some applications, pendelgravimeters have played a significant role in the historical development of gravity measurements and continue to be valuable in specific scientific and technical fields requiring precise relative gravity measurements.