Answer:
What you do to determine the length of something
What object has keys that open no locks, space but no room, and you can enter but not go in?
I'm the son of water but when I return to water I die. Who am I?
You can carry it everywhere you go, and it does not get heavy. What is it?
Break it and it gets better, immediately set and harder to break again.
When is it bad luck to see a black cat?