Instructables
Picture of make a water tilt switch
in this little instructable i will show you how simple it is to make a tilt water switch using a few commong household items. do this at your own risk! i wouldnt recommend using this switch for anything high voltage or outlet (AC) powered. i made it for fun and have no intentions applying it anywhere else (yet). be careful! now lets get started, first gather the things needed which are;
small plastic container (pop bottle, small spice container, etc.)
wire
breadboard+leds and battery (adjust voltage accordingly)
water 

Step 1: Making the switch

fill up the container less than half way and insert two stripped wires at the mouth of the container, keep them seperated, then tighten up the cap of the container and ensure that absolutely no water leaks (very important) shake it up and down and study the container to see if any water has leaked. 
if you cant get your wires in through the mouth of the container then make two small slits (keep the slits seperated by making one, then making the other on the opposite side), run the stripped wires through the slits and secure them using electrical tape, after that cover the slit with hot glue or epoxy to ensure nothing will leak.
i cant stress this enough but ensure there are no leaks! now put this aside and lets look at the simple schematic i made.

Step 2: Simple schematic

Picture of simple schematic
so here is the unofficial schematic. the purpose of this switch is to use position as a state of selection. once the container (switch) is turned upside down it connects the two wires and completes the circuit and alows the electric current to flow. pretty simple right? (enlarge the picture to read the text better) ok now lets move it from the drawing board to the breadboard!
jabujavi1 year ago
Another way to do it safer is to use metalic bearing balls and an aluminium foil pattern. You must do a simple contacts with aluminium foil to ensure good contact. Bearing balls work as water.
out-of-the-box (author)  jabujavi1 year ago
that sounds interesting, i will have to give that a try! thanks for sharing