Why was I so excited about rolling objects?
The previous day the kids (M, L & E) used the spool to put various creatures into the whole in the middle of the spool. It was so deep they could not get the animals back out. They asked me for help getting the animals out after trying to reach in and get it themselves but only to find they could not reach. My hand was too big to fit in the whole even though it may have been long enough. Luckily there is a hole on either side of the spool, so I turned the spool on its side and they were able to retrieve most of the critters by reaching their hands in the spool.
Well, the following day, the curiosity of all four of the preschoolers was invoked when they saw the spool on its side. The tire was also moved to the concrete the day before so I could clean and this combination spiked interest. Two of the kids began to pass the spool back and forth. It was heavy and they used all their might but it easily rolled from one side to the next. Two other kids picked up the tire and began passing that back and forth but they quickly saw that sometimes it would fall over. It was heavy to be picked up. They may not understand at the age of 3-4 why the tire falls or the spool but they are experimenting with motion and materials.
Children become aware that the shape and the texture of an object affects whether it will roll or slide but its shape determines whether it is stable or unstable. After much practice and observation they will soon be able to predict the behavior of any given object.
To continue this investigation, I will add a ramp as another manipulation but I will not tell them about it. When they eventually discover it they will continue the experimentation possibly connecting their past experience with this one, based on their curiosity. Maybe they will chose to roll other or multiple objects off of it.
The idea that kids investigate through play is much more important then schools make it seem to be.