Step 7: Turn it on!
Turn your hose on, and then use the flow control valves on the y adapter to adjust the flow.
The water should come out fairly fast, but it needs to be as droplets and not a continuous stream. A continuous stream won't give the charges a chance to break away from the source, which is grounded.
Ideally, the droplets should begin to form just above the can, before it passes through it. I found that it wasn't very hard to get this working properly without much adjustment.
The water also shouldn't drip on the can, but pass through it instead. A little splashing is normal and doesn't seem to affect the generation of electricity.
Once the water begins flowing, it should only take a few seconds for the first spark to appear. The more individual water droplet streams, the faster and more often you will get sparks!
Watch the video for close-ups of the sparks in action (Fast-forward to 34 seconds to go right to the sparks!):