There are Valentine cards, ecards, and gifts for every taste imaginable! If you don't find a card or image that perfectly expresses your sentiments, you can easily make your own. And if you lack the imagination, skills, or time to create one, someone else probably has just what you're looking for. The scientific community is no exception -and they take advantage of every opportunity to make a pun when they can. Here are some valentines from different scientific disciplines. Keep in mind that for almost every image here, you can find follow the links and find more clever science valentines.
1. General Science
Aaron Lurch put his imagination to work to create a valentine for his wife Mindy. The result was a display worthy of any 7th grade science fair project, complete with a graph of his results. At his site, you can click to enlarge this picture enough to read it -it's quite clever!
David Friedman at Ironic Sans made several scientist valentines. This one features, of course, Charles Darwin and his theory of natural selection. Others depict Sir Isaac Newton, Carl Sagan, Marie Curie, and Albert Einstein.
3. Behavioral Psychology
Alex at Neatorama set out to represent the scientists who had not been enshrined in valentines in Friedman's collection. Besides Pavlov, you'll find Stephen Hawking, Amedeo Modigliani, Archimedes, and Nikola Tesla expressing their romantic sides.
Not to be outdone, Jack of Science made up a collection of valentines that used scientific puns, like this one that illustrates capsaicin. At least I'm pretty sure that's what this is.
5. Computer Science
Garrison Dean created science fiction valentines for io9 last year, including this creepy sentiment from HAL9000.
Maybe you can help me out on this one. There's no explanation of what this image really represents (besides love), and the original has been deleted. I think it may have something to do with DNA sequencing.
Update: Natalie helped me out (thanks!):
It's the result of electrophoresis, where molecular biologists inject DNA samples into a gel and then use electric current to run them across the gel, since DNA is negatively charged. The banding patterns created, like in the image above, are then compared for similarities. For any forensics junkies, this is how they actually do DNA fingerprinting.
Sheila at Cheeky Magpie made a variety of valentines in the shape of an anatomically correct heart. She also posted the basic pattern that you can print out and use yourself. Hey, it's a heart! It could be worse!
Gotta love fractals, which are cool in any form. Randall Munroe of xkcd stuck infinite hearts into this Sierpinski valentine. In 2010, he posted a bittersweet valentine invoking the scientific method.
Dr. Phil Plait, who regularly addresses the issue of pareidolia in outer space and elsewhere, created a valentine with the "face on Mars" that we've all seen.
Stephanie Burrows makes real cardstock valentines for sale at Etsy. A set of 16 feature 8 different scientists saying something you'd expect them to for the holiday.
11. Marine Biology
Science, love, and the horrors of the deep made cute, as happens a lot on the internet. That's P.Z. Myers' cephalopod valentine, because even cuttlefish like to cuddle!
Microbes proliferate in Petri dishes and agar plates, sometimes in colonies that form interesting patterns. However, this one was modified especially for Valentines Day to express the proper sentiment.
Scientists and science geeks have options besides valentine cards and images. You can pass along some science poetry from this roundup at The Scientific Activist. Or share some valentine experiments, courtesy of Steve Spangler. Spangler has more suggestions this year for injecting a little science into your Valentines Day activities, no matter whether you are a scientist or not.