Letting It Roll: Inclined Planes in East PM
By Adrienne Gelpi Lomangino, Head Teacher
Teacher: Brigid thinks that people go down [the ramp] slower than the ball because balls have air in them.
Zachary H.: They don’t because balls are round and wheels are round, but people are heavier than balls so they can also go faster because they’re kind of—they’re flat on the bottom, and people are flat, but they’re heavier than balls.
Teacher: So you said that balls are round and that people are heavier. So do we go down slower because we’re heavy or because we’re not round?
Zachary H.: Because we’re not round and we’re heavy.
This exchange occurred in East PM during exploration of motion on inclined planes, using balls, wheels, and ramps. The exploration began with rolling wheels of varying size, shape, and weight on the hills in the East yard. Within this mixed-age setting, with diverse languages spoken, the children and teachers came together to test, observe, manipulate, and try again.
From the beginning, the children initiated their own experiments, testing possibilities. For example, after rolling wheels in succession, children began releasing two at a time. The children’s cheers, focused gazes, and dashing pursuits of the wheels revealed their captivation by these objects in motion. During subsequent weeks, the teachers and children used hollow blocks, boards, and climbing structures to create inclines of varying heights and lengths. They even modified the ramps, creating long inclines between climbing structures and traversing through barrels. Most children ran in pursuit of the object, while others gazed riveted at the object until it came to a stop.
The children tested both wheels and balls on these ramps, examining the effects of the rolling objects’ size, shape, and weight on the speed or distance traveled and the impact with other objects. The addition of boards allowed the balls to travel farther and faster, leading to observations such as “See, that one went farther than that one, but that wheel and ball went the farthest.” More extended discussions of motion occurred among teachers and peers:
Teacher: Do you think that the wheel will go higher if the ramp is higher?
Kenji: Of course it will. I have a better idea. Let’s make the wheel jump really high.
Gavin: That’s not a good idea. It will go off the side.
Teacher: Well, let’s try both ways and see what happens.
Gavin: See, it goes faster with the ramp like this. The smaller wheels jump and the bigger wheels go to the side.
Kenji: The bigger wheel gets more balance because it is fatter, but the smaller wheel jumps higher.
Meanwhile, children examined motion on a smaller scale inside the classroom as they rolled cars and cylinders of different diameters down ramps. As a recurring exploration of momentum, children placed cars at the bottom of the ramp and observed the outcome when they were hit by rolling objects. Outside, children examined momentum through dramatic play. Using cones and bowling pins, the children constructed a “bowling alley.” They wrote lists of the children who wanted to bowl, created tickets for them, and recorded their “points” with each release.
During snack time and story time, the teachers prompted discussions of motion that incorporated a wider range of children’s ideas. For example, the following exchange occurred during story time:
Teacher: How can we get the block to roll all the way across the carpet?
Kenji: We need a higher platform.
Kate: Give it a big push.
Marc: Put a flat board on one of the shelves [block shelves].
Madeline: Use one of the blocks from outside.
Zachary H.: Get a blanket and tie it on each side [of the block area]. Roll a block on it.
Lucy: Put it on top of one platform with a little block underneath the big block.
The increasing interest in balls, ramps, and wheels also led to collaborative wheel games. In one such game, dubbed “Bingo,” several children rolled balls and wheels on a ramp structure in which an initial ramp led to two smaller peaks made from slanted blocks:
If the ball or wheel rolled along the entire length, the children called out “Bingo!” If it fell off part of the way down, they called out “No Bingo!” In an expanded form of this game, a couple of children exclaimed “Excellent!” instead of “Bingo!” When the wheel rolled only part way down the ramp before plunging over the side, they chimed, “Mediocre.” Finally, they called immediate derailments “Lousy.”
Children who varied in age and language fluency found ways to participate together in examining inclined planes. Children not yet three years old and others who rarely spoke English clambered up climbers to release balls alongside five-year-olds who made predictions and offered explanations. Children did not need to use English to collaborate on creating dams for the balls or on setting up pins for the next round of bowling.
In a 1978 book, Physical Knowledge in Preschool Education: Implications of Piaget’s Theory, Constance Kamii and Rheta DeVries observe that examining motion on inclined planes is a “physical knowledge activity” in which children act on objects and observe outcomes. Such activity fosters not only children’s specific knowledge of objects in the physical world, but also more general thinking skills and knowledge. “Inclines seem particularly rich in potential,” say Kamii and DeVries, “because they enable a child to make an object move by letting go, without applying any force to it…. An incline, therefore, gives the child a special occasion to observe the interactions among objects as well as to structure spatial relationships.” A child’s suggestion for how to make a ball go fast illustrates just such structuring of spatial relationships:
Lucy: Put that thing [A-frame] way back here. Stack blocks and more blocks all the way up to where it is. Like stairs kind of. Then you put one little ramp on the highest bar. And then you roll it down the ramp. Then it lands on the little stairs that we put and it does poppity-pop down the stairs.