Gravitational Constant Measured by Means of a Beam Balance

Abstract

We present a new method to measure the gravitational constant $G$. A beam balance compares the weight of two 1-kg test masses and measures the gravitational force of two field masses with a statistical uncertainty of $10\mathrm{ng}$. Two vessels in a refined arrangement are used as field masses. They have been filled with water as a test. $G$ has been determined with an uncertainty of $240\mathrm{ppm}$. The next step is to fill the vessels with mercury. Because of the larger signal and further refinement of our experiment, we hope to reach the design uncertainty of $10\mathrm{ppm}$.