羽毛球點解會o係空中轉

I think it will turn is because of the player hit the ball and the ball is light. and... the ball's bottom is the most heavy so when the ball drop , the bottom is
meet the player

the rotation is due to the geometry arrangement of "feathers", just like the rotating 竹青蜓

因羽毛球的底部有個較重的東西,
而羽毛較輕.

要講埋伯努利原理