Answer:
Until I am measured I am not known, Yet how you miss me when I have flown.
It is a path of cow juice spread across the sky but cannot be seen by the naked eye
Always old, sometimes new. Never sad, sometimes blue. Never empty, sometimes full. Never pushes, always pulls.
My teeth are sharp, my back is straight, to cut things up it is my fate.
What can touch someone once and last them a life time?
If lightning strikes an orchestra who is the one most likely to get hit?
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?