At the top is a reservoir (bottle) for the fluid (green water thickened with xanthan gum, in this case) which feeds a
solenoid-controlled valve to create the water drops. The camera is at the bottom right, and the drop illumination
is provided by a flash gun connected to the camera via a cable. The flash exposure is set to manual, dialling in
at 1/32 power. This ensures a very short duration flash to freeze the motion (and not a short shutter speed).
It can be a messy operation, so there is a large bowl to collect any wayward splashes!
(The black thing at the top, behind the water bottle, is a lamp; nothing to do with the drop experiment!)