Ping Pong waterer

I removed the other blog post about the rain barrel water distributor. Here is my new design:

Basically there is a rain bucket with a hose going to the bottom, and on the other end there is the top of a plastic soda bottle with a ping pong ball in it. Water will I hope drain from the rain barrel that's at a higher elevation but as the water gets higher in the container being filled the ping pong ball floats until it blocks off the water from filling it any more. Then as a pet or a plant drinks the water the ping pong ball sinks with the level of the water and open the flow from the barrel again.

*EDIT*
Works like a charm here is a picture. The orange thing in the neck of the bottle is the ping pong ball. The only thing different from the design above is there has to be a hole in the bottle just below where the ping pong ball seals it off so the air can get out of the bottle.

To see how this problem is normally solved look at this:
http://en.wikipedia.org/wiki/Float_valve
Mine's a lot simpler isn't it?