Summarize:

Pick something you think is a passion, and talk to a friend about it. When you’re done talking, ask them if you seemed intense or casual about it. If you talk for a long time and they say you were intense about it, that’s a sign it’s a passion.  When you are talking about your passion, you will probably speak louder, faster, and more. You’ll get worked up talking about it. You’ll sound excited and won’t want to stop talking. If they say you didn’t seem to know very much, or you kept a pretty even tone, it’s a hobby. You’ll feel much more excitement talking about a passion than you will talking about a hobby. Choose something you do every week, or every few days, and stop doing it. If you think about it daily, miss it, and don’t feel like doing anything else, you’ve found something that’s a passion. If it doesn’t bother you to stop doing it, it’s likely to be a hobby.  If you typically play ultimate frisbee every Wednesday, skip it this week. If you fill the time with something else and barely think about it, it’s a hobby. Take a break from editing the film footage you are always shooting. If after two days you can’t think straight because you want to be at the computer, you know it’s a passion. Get an opinion besides your own from a set of standardized questions. Be honest about your feelings on the activity. You’ll be able to learn how much it means to you from a set of questions and not just your own thoughts.  A quiz like this can’t tell you without a doubt whether something is a passion or a hobby. However, it forces you to be more objective about the activity than you are on your own. The websites of Clarity on Fire, Goodnet, and Paid to Exist offer different types of quizzes that help you gain a better idea of what hobbies could be passions.
Tell someone about the potential passion, and ask for their reaction. Take a break from the activity for a week. Use a quiz as an objective guide.