The best science lines work because the listener has to know a little to get them. Use them on people who actually like the subject: a lab partner, a fellow student, the friend who corrects everyone's units. Said to someone who hated chemistry at school, even a good one just sounds like homework.
Keep the science accurate. A pun built on a real concept earns a laugh, and a playful correction is half the fun; one built on a mistake earns only the correction.
Study groups, labs, museum late nights, pub quizzes and anywhere two people are already pretending to understand the same lecture. The shared subject does most of the work, so the line only needs to be clever enough to show you were paying attention.
If it falls flat, explain it. Unlike most pick up lines, a science line that needs explaining still starts a conversation, and someone who asks you how entropy works is already talking to you. For the rest of the nerd canon, from Star Wars to Dungeons & Dragons, see the nerdy and geeky collection.
