Explain the Cavendish experiment? |

The Cavendish Experiment was an experiment conducted between the years 1797-1798 by Henry Cavendish. The Cavendish experiment actually was based on and utilized equipment developed by John Michell who died in 1793 before being able to complete the work. Following Michell's death, Cavendish was given an experimental device developed by Michell to determine the mass gravity of earth, which he then used to develop his own replica. Through use of this device Cavendish was able...

The Cavendish Experiment was an experiment conducted between the years 1797-1798 by Henry Cavendish. The Cavendish experiment actually was based on and utilized equipment developed by John Michell who died in 1793 before being able to complete the work. Following Michell's death, Cavendish was given an experimental device developed by Michell to determine the mass gravity of earth, which he then used to develop his own replica. Through use of this device Cavendish was able to determine the mass density of the earth. Later, scientists were then able to determine the gravitational constant from Cavendish's results.

Cavendish was able to determine the mass density of earth through use of his reconstruction of Michell’s apparatus. He did this by making a large torsion balance apparatus. The apparatus contained a six-foot wooden rod. On each end of the rod were two identical lead balls. Located about nine inches from these smaller lead balls, on a separate suspension system were two 12 inch, 348 pound, lead balls (Figure). Because the larger balls had a faint gravitational attraction to the smaller ones, they would cause the apparatus to rotate, spinning the wire holding the apparatus up. Once the twisting rod reached an angle where it balanced the gravitational force between the small and large balls the system went into equilibrium and stop moving.  

Cavendish was able to use the final angle of the rod, along with the torsion coefficient of the wire, which he calculated himself, to determine the gravitational force between the two balls. Knowing earth's gravitational force on the smaller balls by measuring their weight, he was able to create a ratio between the gravitational force of earth on the smaller balls and the force between the small balls and larger balls. Using this ratio and Newton's law of gravitation, he was then able to determine the mass density of the earth. Hope this helps!