Recently, I joined a fan-fiction challenge on another forum and had to write up a story based upon another fan's request. Now, I've written some fan-fiction in this sci-fi universe before, but I'll be honest. I've never written any actual *science fiction* there. I tend to write angst-ridden, dramatic pieces. This was a new one for me, but I rose to the challenge. I invented a universe complete with alien beings. And before I knew it, I was searching the Internet to learn about theta waves in the brain, consulting other people about diseases, and researching light waves.
Writing science fiction can expand your view of science in ways you wouldn't expect. If you're not a big science fiction fan, start with a familiar universe that's friendly to fan-fiction and write a small scene. There are a number of forums out there, dedicated to different sci-fi fandoms, where you can post your work. (My piece, Journey to the Theta Region, is posted at Gatchaman Fanfic Archive.)
The best part? When you explore your new world, you just might learn a thing or two about ours.