Description
After lunch one day, first-grade teacher Mr. Fox calls his students to the carpet area so that he can show them a “curious thing.” Once the children are all seated and attentive, he puts a large fishbowl in front of them and fills it with water. Then, out of his jacket pocket, he pulls a piece of granite a little smaller than a golf ball and holds the stone over the bowl.
“What’s going to happen when I drop this stone into the water?” he asks the children. “Do you think it will float like a boat does?”
Several of the children shout, “No, it’s gonna sink!” Mr. Fox drops the stone into the water, and, sure enough, it sinks.
“You were right,” Mr. Fox says. “Hmm, I have another stone in my pocket.” He pulls out a much larger one
—in this case, a piece of pumice (cooled lava) that is filled with tiny air pockets. “When I was traveling last summer, I found this at the bottom of an old volcano. Do you think this one will sink like the other one did?”
The children declare that it will definitely sink. Mr. Fox drops it into the fishbowl, where it momentarily submerges and then floats to the surface. “Hmm, what just happened?” he says as he looks inquisitively at his class.
Many of the children gasp with surprise. When a girl named Cora insists, “You didn’t do it right!” Mr. Fox retrieves the pumice and drops it in the water again, with the same result. “No, no, that’s impossible!” Cora yells. “Stones always sink
—always!” She rubs and shakes her head, almost as if she’s a bit upset. (Case based on similar lesson described by Hennessey & Beeth, 1993.)
Cora is noticeably surprised and possibly upset when she sees the pumice float.
A. Use one or more concepts from Jean Piaget’s theory of cognitive development to explain why Cora reacts as strongly as she does to the floating pumice.
B. Again drawing on Piaget’s theory, explain why Mr. Fox intentionally presents a phenomenon that will surprise the children. (150 Words)
Imagine that you perform the same demonstration with high school students rather than first graders. If you were to make use of Vygotsky’s theory of cognitive development, which one of the following approaches would you be most likely to take in helping the students understand the floating pumice?
A.
Teach the concept of density, and explain that an object’s average density relative to water determines whether it floats or sinks.
B.
Praise students who correctly predict that the larger stone will float, even if they initially give an incorrect explanation about why it will float.
C.
Before performing the demonstration, ask students to draw a picture of the fishbowl and two stones.
D.
Drop several light objects (e.g., a feather, a piece of paper, a small sponge) into the fishbowl before dropping either stone into it.
