Now consider Harriet's school on Friday afternoon. The road outside is under water.

Here is the class weather table for the last three days.

The class table: 40, 44 and 38 millimeters of rain on Wednesday, Thursday and Friday, with the wind from the west.

And here is what else the class observed.

Three more observations from Friday afternoon.

The class has three explanations.

Maybe a pipe under the road burst, maybe the river rose over its banks, or maybe someone left a hose running.

A burst pipe leaves a hole in the road and a fountain of water. Nobody observed either one.

A garden hose cannot cover a whole street with water.

The river explanation fits the three days of rain, the high brown river, and the water across the street.

Does it fit what the class observed? A red cross for the pipe, a green tick for the river, a red cross for the hose.