NOT THAT POWERFUL
Gravity is the weakest of the forces. A bar magnet will electromagnetically pull a paper clip upward, overcoming the gravitational force of the entire Earth. Physicists have calculated that gravity is 1040 times weaker than electromagnetism. While gravity’s effects can clearly be seen on the scale of things like planets, stars and galaxies, the force of gravity between everyday objects is extremely difficult to measure. In 1798, British physicist Henry Cavendish conducted one of the world’s first high-precision experiments to try to determine the value of G, the gravitational constant.
Cavendish built what’s known as a torsion balance, attaching two small lead balls to the ends of a beam suspended horizontally by a thin wire. Near each of the small balls, he placed a large, spherical lead weight. The small lead balls were gravitationally attracted to the heavy lead weights, causing the wire to twist just a tiny bit and allowing him to calculate G.