The Law of Gravity Explained

The law of gravity says that if you drop two objects at the same altitude, they will both reach the ground at the exact same time. But in a vacuum chamber on earth this is not true. The feather has a very small mass and it's got a large surface area so its journey towards the ground is slowed down by air around us. People still need to wear spectacles despite advances in technology. Doctor nishc: I sometimes think there is a spectacle company mafia behind all this dependence on wearing glasses.