Answer:
What can be heard and caught but never seen?
It cannot be seen, it weighs nothing, but when put into a barrel, it makes it lighter.
I know a word of letters three. Add two, and fewer there will be!
What travels from house to house and is sometimes narrow and sometimes wide but always stays outside?
Tool of thief, toy of queen. Always used to be unseen. Sign of joy, sign of sorrow. Giving all likeness borrowed.
As round as an apple. As deep as a cup. All the king's horses can't pull it up.
Difficult
Animal
Easy
Food
Funny
Kids
Logic
What am I?