Answer:
What can be measured but not seen?
They try to beat me, they try in vain. And when I win, I end the pain.
The weapon of choice to create the biggest shock.
What can be swallowed, But can also swallow you?
It's equally comfortable in an orchestra and a geometry textbook. What is it?
Long and slinky like a trout, never sings till it's guts come out.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?