In 1750, French scientist Bouguer used the “plumb line method” principle to measure the weight of the earth on the top of Chimborazo, Ecuador, in South America, but the small gravitational force between the mountain and the lead ball was affected by the mountain wind and various Therefore, the experiment was not successful.
In 1774, British scientist Neville Muskelling once again used the “plumb line method” to conduct experiments on a steep cliff in Perthshire. During the experiment, he tried to avoid the influence of mountain wind and vibration, but it still ended in failure.
In the journey of measuring the weight of the earth, although many scientists have returned without success, there are always devout “pilgrims” “going forward” on the road of science and truth.
In 1750, Cavendish, who had just turned 19 years old, asked John Michel of Cambridge University for advice and mastered a set of measurement methods: hanging a magnetic needle in the middle of a rope, and expressing the magnitude of the force by the degree of twist of the string, And through this method, the method of measuring tiny force is derived. He tied two small lead balls to both ends of a slender rod, and then hoisted it from the middle, and slowly approached the two large lead balls to the small one. Due to the action of gravity, the small lead ball would rotate slightly . By calculating the degree of twisting of the small lead ball, we can measure the magnitude of the gravitational force between the two balls, and then calculate the weight of the earth. However, despite numerous experiments, Cavendish was unsuccessful.
After repeated defeats and repeated defeats, Cavendish has made breakthroughs after repeated scrutiny and improvement. After many attempts with light and the like, he finally eliminated all distractions and created an instrument that could measure tiny forces, which he called a “torsion balance.”
Cavendish twist experiment
It took Cavendish nearly 50 years to finally measure the weight of the Earth in 1798—about 60 trillion gigatons. In 1810, the unmarried Cavendish died in London, England. He spent his life only for one value; his great achievements played a crucial role in astrometry; his “torsion balance” was recorded in history. , he is also known as “the first person to call the earth”!
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