The children's interest in the flow of water was still high when the weather became too cool for water play. Wondering if they might make a connection between the flow of water and the way a ramp works, we offered balls to go with the lengths of gutters they had been using. An advantage to taking water out of the equation was that the gutters could come out of the sand. The children used the hill as a sort of head start for the inclined planes they knew they needed.
Here is a gallery of some of the children's exploration with ramps and balls from late Autumn, through Winter and Spring. Click on the upper left corner of a picture to see the captions.