Flowmometer

This was made for my daughter's science fair project.
It is for measuring the flow rate of very thick substances over time.
The valve / stopper is inserted to block the flow. Then the block is removed and the flow
length is measured after a chosen amount of time.

To measure the flow, a ruler is put in the cut-out on the side of the Flowmometer.
Then the measurer is moved to where the flow stopped and that is how you get your measurement.

We used a C-THRU 12" stainless steel ruler and measured using millimeters.
A 6" ruler would fit a lot better.

The vessel in the Flowmometer where the substance is placed is close 1/4 cup in volume.

All pieces were printed with a 0.4mm nozzle with a 0.1mm layer height.

The measurer and valve / stopper will need to be printed standing up for the dimensions to be perfectly correct and for the bottom of those to be perfectly flat.
The STL preview is displaying them upside down.

The CAD program used was FreeCAD 0.21.1
I have includ