This, my first instructable, will show you how get addicting audio visualizations using ordinary tap water.
Caution: when completed, this can be highly addicting.
Caution: this could potentially harm your speakers. It has not harmed mine for any long period of time, but it could happen.
Have fun!

Step 1: Remove the Speaker Cover.

If your speaker is already naked, great. If not, you will have to remove the cover. Some speakers have a cover that just needs to be pulled, some you have to unscrew the whole housing to remove whatever's in front of it.

Step 2: Find the Right Speaker.

You want to use a speaker with a little dome in the middle, not one with a funny little flattish thing. The domed ones have a waterproof design without the waterproofed material, the others have spaces through which water can travel.

Step 3: Waterproof the Cone and Dome

The first time I ever did this, I skipped this part. I do not believe that it is a necessary step, but it is probably a very good idea. Without waterproofing, water could damage the speaker cone. I have had water through a bad speaker and into the electrical bits, but it was all better after it dried out.
So, find your favorite waterproofing material (I used polyurethane) and apply it to the speaker cone and dome but NOT to the rubber around the edge of the speaker which allows the cone to move. At least not to the whole thing, it's not a crime if you get a little on there.

Step 4: The Magic!

Pour a little bit of water into the speaker cone. It can cover the dome or not. Play music through the speaker. You will probably have to turn it up a bit, but then you will see pattern form on the surface of the water.
There are three basic patterns:
The first and simplest is rings, and it looks like a standing ripple. It will change dimensions depending on the music.
The second happens with more complex music and especially bass. It appears as a bunch of high but small radius circles that will move around and interact with each other to create a constantly moving interference pattern.
The third happens when you turn the music up quite loud. The water will jump (I've had it go two and a half feet) and continue to do so in a lovely shower of drops in the loudness which will get anything within a foot or two damp.
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