This is a simple test rig (mostly 3d printed) based on a design by John Walker (http://www.fourmilab.ch/gravitation/foobar/ Gravity is a weak attraction between two objects (beyond that, things get pretty speculative). This "gravity bar" is a rod with lead weights on the ends. It is suspended from a ladder using 6 pound test fishing line. A "daggerboard" on the bottom of the rod sits in water to dampen rotation.

On August 12 I added a longer bar (longer bar, extenders and sphere holder)