S.F.B. – Worthington Made Easy
S.F.B. or Shoot From Below is a jet of pressurised liquid that is shot upwards and is used to collide with falling drops to create a collision. Traditionally the rising jet (called a Worthington Jet) is created by a falling drop of liquid. The rising Worthington jet is not guaranteed to rise truly perpendicular so sometimes the collision may not be as expected. However, with a pressurised jet it is possible to place the height of the jet where you want to capture a collision. Very often the jet is visible under the collision and because I personally find that distracting, I started to use fountains to surround and disguise the jet. Because the jet is pressurised it is also possible to shoot it up with enough force to create much more complex collisions than would be achievable using a Worthington jet as the target.
There is not much to say about an S.F.B. jet as it really is just a jet of water. However it does give a nice stable target for falling drops. This video is a compilation of a number of collisions that were part of larger fountain captures. There was no camera angle changes so it gives an indication of similar the jet height is. That really is not a concern if you have established a nice perpendicular jet and only have one solenoid above releasing drops straight down onto the jet. But the consistent height can be very helpful when you are using more than 1 solenoid to release drops from above.