Willie the Hamster

Ms. W. encourages students to engage in an investigation initiated by a question that signals student interest. The context for the investigation is one familiar to the students—a pet in the classroom. She teaches some of the important aspects of inquiry by asking the students to consider alternative explanations, to look at the evidence, and to design a simple investigation to test a hypothesis. Ms. W. has planned the science classes carefully, but changes her plans to respond to student interests, knowing the goals for the school science program and shaping the activities to be consistent with those goals. She understands what is developmentally appropriate for students of this age—she chooses not to launch into an abstract explanation of evaporation. She has a classroom with the resources she needs for the students to engage in an inquiry activity.

[This example highlights some elements of Teaching Standards A, B, D, E, and F; K-4 Content Standards A and B; Program Standards A, C, and D; and System Standard D.]

George is annoyed. There was plenty of water in the watering can when he left it on the windowsill on Friday. Now the can is almost empty, and he won't have time to go the restroom and fill it so that he can water the plants before science class starts. As soon as Ms. W. begins science class, George raises his hand to complain about the disappearance of the water. "Who used the water?" he asks. "Did someone drink it? Did someone spill it?" None of the students in the class touched the watering can, and Ms. W asks what the students think happened to the water.

Marie has an idea. If none of the children took the water, then it must be that Willie, their pet hamster, is leaving his cage at night and drinking the water. The class decides to test Marie's idea by covering the watering can so that Willie cannot drink the water. The children implement their investigation, and the next morning observe that the water level has not dropped. The children now have proof that their explanation is correct. Ms. W. asks the class to consider alternative explanations consistent with their observations. Are they sure that Willie is getting out of his cage at night? The children are quite certain that he is.

"How can you be sure?" asks Ms. W. The children devise an ingenious plan to convince her that Willie is getting out of the cage. They place his cage in the middle of the sand table and smooth the sand. After several days and nights, the children observe that no footprints have appeared in the sand, and the water level has not changed. The children now conclude that Willie is not getting out of his cage at night.

"But wait." says Kahena, "Why should Willie get out of his cage? Willie can see that the watering can is covered." So the class decides to leave the cage in the middle of the sand table and take the cover off the watering can. The water level begins to drop again, yet there are no footprints in the sand. Now the children dismiss the original idea about the disappearance of the water, and Ms. W. takes the opportunity to give the class more experiences with the disappearance of water.

At Ms. W.'s suggestion, a container of water with a wide top is placed on the windowsill and the class measures and records changes in the water level each day using strips of paper to represent the height of the

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