A silly little puzzle..
Answer this now..
I have a weighing scale and there is an empty plastic bottle on the scale. A certain reading is shown in the scale. Now, a fly enters the mouth of the bottle. Note, it does not go to the bottom of the bottle. It's just flying inside the bottle. Is there a change in the weighing scale? Why?
P.S: [This qn is asked in a puzzle competition in our college. I have guessed the answer, but I dont know it for sure.]