Good Riddles

Question: What is as big as you are and yet does not weigh anything?

Question: My name is Ruger. I live in a farm. There are four other dogs in the farm with me. Their names are Snowy, Flash, Speed, and Brownie. Who is the fifth dog?

Question: Without me, nothing exists. What am I?

Question: Leap Year is every 4 years. True or False ?

Question: A man walks into a completely dark room. There is a box on a table at the other end of the room and immediately the man knows one of the contents of the box. He cannot smell, see, or hear it.

How does he immediately know what is inside?