Gravity shows the shape of Earth (I need your help!)
I need your help! A few posts ago , I tried to measure the shape of the Earth using my acceleration chips in my macbook. After a quick sensitivity analyses I found out that the precision of the chips was not sufficient to do this exercise. However, I really want to see if I can measure the curvature of the Earth by looking at its gravity field. So instead of high-tech measurements with my macbook, I want to see if a low-tech solution (a string pendulum) is more accurate. The basic physics behind a pendulum measurement. The relationship between the period (T) of the pendulum and its length (l) and the local gravity (g) is (yes, high school again): Well, this is not entirely correct, but for this experiment (keep the amplitude low!!!) it is good enough (take a look here to get a better relationship). So, to measure the local gravity (g) we need to know the length of the pendulum (half-measure!!!) and the period of the pendulum. So, what is my set-up? A p...