Apples fall because they're ready to fall, and they're heavy. The glass fell because it was heavy, and it was on the edge of something and got shaken or pushed off. No further explanation needed in the minds of 99% of people. Feathers fall slowly because they're so light the air blows them around first. Things fall towards the ground because the ground is the stopping point for everything. Imagine if things fell towards the sky or the nearest tree. The world just wouldn't work. Therefore, they fall to the ground.