EDUCATIONAL PSYCHOLOGY

Chapter 6, page 97

Problem 6.4: Evaluating teaching:

Instruction for conceptual change

Sharon, a fifth-grade teacher, is making plans to teach the next science unit on

matter and molecules. She finds the following passage and diagram in her

textbook.

Water is made of tiny molecules moving around all

the time. The molecules in water never stop

moving. As they move, they bounce against

each other over and over.

Evaluate this textbook passage in terms of whether it is misleading in a way

that promotes any alternative conceptions. If it is, what alternative

conceptions might it promote? Should Sharon adjust her instruction in any way

to make sure that students do not misinterpret this passage and diagram? If

so, how?

Response: One serious problem with this passage is that both the text and the

diagram strongly imply that the molecules are in water—that water molecules

and water are different, and that the molecules are swimming around in the

water. Notice that the textbook passage states that water molecules are in

water and that the diagram shows a wavy gray background that students can

readily interpret as water. Thus, this text and diagram are likely to contribute

to some students developing an alternative conception that water molecules

are little particles of some kind that are surrounded by water. If Sharon

realizes this, she will want to clearly explain to students that this idea is not

what is intended by the text. She might explicitly note this alternative

conception and explain how the scientific explanation is different—explaining

that the water molecules are the water, not that they are in the water.

NOTE: Another issue that could be considered is that this diagram

depicts water molecules as single circles rather than as the well-known three-

atom molecule containing one oxygen and two hydrogen atoms. The

argument for presenting a simple idea first is that students are not yet ready

to learn about atoms. There is as yet little or no research on whether it is

better to teach simpler conceptualizations before moving on to more complex

conceptualizations later or to teach more complex conceptualizations from the

start.