1. You do science
2. You like it
3. You drink orange juice out of old acid beakers
4. Your car has a bumper sticker that says 'I'm a scientist'
5. You see a sewer rat and arrogantly proclaim 'I could grow an ear on that'
6. You've never owned a trans am
7. Your favorite character on breaking bad is the main guy, the sciency one
8. You KNOW how they get the bones out of the boneless chicken wings
9. You light your cigars with a bunsen burner
10. You've had sex wearing nothing but a white lab coat
11. People call you up and say 'I've got a science question for you'
12. You know the answers to their questions
13. You're fond of starting sentences with 'if my calculations are correct'
14. People introduce you with 'this is my friend, he's a scientist'
There you go - if it turns out you are a scientist then congratulations -
if not it's ok, you could still be one one day, I recommend starting
with number 12. Knowledge is power!