By using trial and error I found the best way to create a droplet of water is to use an hypodermic needle.
The medical syringe will apply a very tiny drop whereas the syringes provided with inkjet refill kits will create a larger droplet. Also the inks are very useful for colouring water when doing a water splash.
This photo
http://media.digitalcameraworld.com/...6/hypo-fun.jpg is of a refraction photo using a syringe suppied with ink.
Harry