Awhile back I finally tried something I've seen a lot online, but thought it wouldn't work for me. I figured I needed better lighting, but after some success with catching drops in mid air (see this post), I felt more confident about catching the splashes.
It ended up being really fun and slightly addictive. I want to do it again sometime once I track down some new backdrops.
Here's basically what I did: I filled up a clear glass bowl of water and stacked it on top of a smaller bowl placed upside down in the sink. This was just to give me the height I needed for a good camera angle--you can find other methods, of course.
Then I used my macro lens, tripod and external flash. I pointed the flash up at the ceiling for reflective light. Then I turned the faucet on a slow drip. Here's what my setup looked like:
I wanted to add some color to help the drops and splashes show. That's where I had fun experimenting with different scrapbook papers I had on hand.
I started with something fairly pale but the more vivid colors seemed to work better in showing detail (I had to pump up the color in the above photo).
The most effective paper was one with a very glittery/shiny texture. It helped bring out more dimension in the drops with my flash reflecting off the foily surface. I have it pictured here, though it's hard to make out the sparkles:
But this first method of having that same paper under and behind the bowl was a little too much craziness in the resulting images. The glittery appearance detracted from the droplets. I found having this glittery paper under the bowl gave a nice color from below, and then putting something else non-glittery as a backdrop meant the drops could have two colors intertwining.
It's okay if you see something different in these (if anything besides just water). Those were my first impressions and they have stuck with me each time I re-look at the pictures, but let me know if you disagree. :)