The rings beside the watering cans

An original exposition about an invented watering trial.

We needed a quick way to record how many full watering cans were emptied on each row of newly planted trees. Our paper record sheets had become soft in the rain, and volunteers did not always have a pencil with them. We placed wooden rings beside the water container instead. Whoever emptied a full can was meant to drop one ring into a metal tin.

An observer counted the full cans independently so that we could compare the ring total with what had actually happened.

At first, the difference of four seemed to show that the method had failed. The observer, however, had seen two volunteers taking turns with the same can. Each apparently expected the other person to move the ring. Before the second trial, we added a card saying, “If you empty the can, move one ring.” That morning, the two totals matched.

The open day prevented us from making a simple claim about success. Although the instruction remained in place, people sometimes left the crowded water container without moving a ring. Clear wording had corrected one problem, but it could not remove every distraction.

The rings still made a useful total visible without interrupting the watering, and neither the tin nor the rings was damaged by rain. However, the total could not show whether water had been poured evenly, spilled on the path or given to soil that was already damp. The system recorded an action, not the quality of that action. We decided to keep the rings as a quick prompt, while using occasional observation to check what their number really meant.

How does the writer explain the strengths and weaknesses of the ring system, and how convincingly does the evidence support the decision to keep using it?