For play, for music, for oenophilia!

Remember when you were younger and you went to a nice restaurant and they served you water in a wineglass? And you learned that if you ran your finger around the rim, you could make the wineglass "sing" with vibrations- and at different pitches, depending on the amount of water into it?

This Instructable shows you how to turn a regular old wineglass into a musical instrument that anyone can play. You tune the glass to find out how much liquid it needs for a given note, then etch the glass with glass etching cream so that the notes are easy to find.
Put some fun back in your wine drinking habit!
Wait, wine is fun anyway.
Now it's more fun.

Step 1: Materials

Wineglass (I used a cheap set of four wineglasses I got at Bed, Bath and Beyond)
Tape
Etching cream
Tuner (you can use your iphone or laptop for this; there are many free services)
optional precision measurement tools
optional extra containers for water

Step 2: Tune Glass

Find a tuner- digital or physical. I googled it and used one that was a web app.
Find out what note your wineglass plays while empty, then successively add water to it, marking the notes you want as you get to them.

But wait! I used post-its and masking tape and scotch tape and NONE of them stayed on while I was tuning the glass. While I was playing, the outside of the glass got wet, and so all the sticky stuff fell off. If you're confident you can keep the tape on, go on ahead and skip the next step, too. If not, read on.

I thought I was going to have to do volumetric modeling and laser etch the thing, which was going to be a pain and terribly unhelpful for the almost-everyone without access to a laser cutter. But then I realized that volume was measurable!

Using a mL plastic syringe, I added precise amounts of water to the glass, jotting down the volumes needed to reach the next note:

D +30
E +16
F +38
G +51
A +88
B 178mL

Step 3: Tuning by Volume

Okay. So this is the clever part. I now knew exactly how much water I would need to add each time to reach the next note. So I got a bunch of little bowls and carefully measured out the additional water needed for each note.

And then, all I had to do was (in order) pour the bowls one by one into the glass- spilling no wetness on the outside!- and mark the new height of the water level with the same tape that didn't work before.

Step 4: Marking Negative Space

Now that you've marked your notes, you're going to be covering up the rest of the glass.
We're going to put etching fluid on that glass, so anything you don't want etched should be well covered.

The little gaps of negative space in the picture are where the notes are (the bottom of each negative bit).

Step 5: Etching

Etching cream is super easy to use. Apply it liberally with a paintbrush, wait 60 seconds, then wash it off. The tape comes off too.

Step 6: Final Product

Ta-da! Look, it's all nice and etched!
Sorry for the water distortions.

If you have stickers or stencils or creativity, you could do lots of cool things with this. You could etch everything except the notes. You could find a way to put the notes' names on the glass.

You can do anything!