Related Experiment Video
Updated: Mar 23, 2026

Demonstrating the Uses of the Novel Gravitational Force Spectrometer to Stretch and Measure Fibrous Proteins
Published on: March 19, 2011
Research on supporting mounts of spheres in measurement of gravitational constant G
Qing Li1, Jian-Ping Liu1, Chao Xue2
1MOE Key Laboratory of Fundamental Physical Quantities Measurements, School of Physics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, People's Republic of China.
Abstract:
The ongoing precision measurement of the gravitational constant G at our group is performed by using two different kinds of methods: time-of-swing method (ToS) and angular acceleration feedback method. In the two methods, the stainless steel spheres are employed as source masses, and the position stability of the spheres is an important parameter, which make suitable mounts for supporting the spheres needed extremely. In this paper, an upgraded three-point mount is introduced and tested in detail. Experimental results show that, for the sphere supported by the three-point mount used in the ToS method, the repeatability, the temperature influence, and the vibration influence are all less than 0.1 μm (about 2 ppm for the value of G). For the sphere supported by the three-point mount used in the AAF method, similar results are obtained, the largest change of the sphere's position is about 0.6 μm, introduced by a temperature change of 1 °C, which also results in an uncertainty of 2 ppm for the value of G.
Related Concept Videos
Gravity between Spherical Bodies
This assumption can be proved easily by showing that the expression for gravitational potential energy between a hollow sphere of mass (M) and a point mass (m) is the same as it would be for a pair of extended...
Gravitation Between Spherically Symmetric Masses
Variation in Acceleration due to Gravity near the Earth's Surface
The difference between the true and apparent weights is proportional to the square of the Earth's...
Measuring Acceleration Due to Gravity
A simple pendulum can be described as a point mass and a string. Meanwhile, a physical pendulum is any object whose oscillations are similar to a simple pendulum, but cannot be modeled as a point mass on a string because its mass is distributed over a larger area. The behavior of a physical pendulum can be modeled using the principles of...
Newton's Law of Gravitation
Acceleration due to Gravity on Other Planets
Astronomical observations are thus used to measure the acceleration due to gravity on other planets. This can be determined by observing the effect of a planet's gravity on objects close to it. The crucial factor that helps in this...

