Reynold's law says that if you has a system of fluid flow, the length times the velocity times the density divided by the viscosity is a constant. That means that if you want to model a system (say a wing in flight or a dam breaking and flooding a town or a storm on a gas giant) you don't have to build a full scale, real speed model. You can get good data from something more reasonable size and speed it you play with the viscosity.

We could build a tank that has two reservoirs of some viscous liquid (like that glycerine) with a shallow sluice connecting them & a pump to keep the flow going (would an aquarium pump work with glycerine?). If we used one of the plexiglass panels for the bridge we could light it or provide contrasting background or whatever from underneath.

This would be a nice companion (or alternative) to a wind tunnel.