Tattoos usually mark someone who is passionate, whether it’s about life, a loved one or even hobbies. And although they’re not the first group we think of when we hear the term passion, scientists are arguable some of the most passionate people in the world with relentless dedication to their work. So naturally, feeling that strongly about science leads to some serious scientific ink. Check out the coolest science tattoos over at the Loom’s Science Tattoo Emporium where science nerds (we say that with love) show off tattoos of DNA strands, rare species of plants and animals, mathematical equations and even a few portraits of famous scientists.

Our favorite scientific tat? The one that urges you to “think periodically.”