Funny Water

In this example, Mr. B makes his plans using his knowledge and understanding of science, students, teaching, and the district science program. His understanding and ability are the results of years of studying and reflection on his own teaching. He usually introduces new topics with a demonstration to catch the students' attention. He asks questions that encourage students to develop understanding and designs activities that require students to confirm their ideas and extend them to situations within and beyond the science classroom. Mr. B encourages students to observe, test, discuss, and write by promoting individual effort as well as by forming different-sized groups of students for various activities. Immense understanding, skill, creativity, and energy are required to organize and orchestrate ideas, students, materials, and events the way Mr. B. does with apparent ease. And Mr. B. might repeat an activity five times a day, adapting it to the needs of different classes of students, or he might teach four other school subjects.

[This example highlights some components of Teaching Standards A, B, D, and E; Professional Development Standard C; 5-8 Content Standard A and B; Program Standards A, B, and D; and System Standards D.]

Mr. B. was beginning a unit that would include the development of students' understanding of the characteristic properties of substances such as boiling points, melting points, solubility, and density. He wanted students to consolidate their experiences and think about the properties of substances as a foundation for the atomic theories they would gradually come to understand in high school. He knew that the students had some vocabulary and some notions of atomicity but were likely not to have any understanding of the evidence of the particulate nature of matter or arguments that support that understanding. Mr. B. started the unit with a study of density because the concept is important and because this study allowed him to gather data on the students' current understandings about matter.

As he had done the year before, he began the study with the density of liquids. He knew that the students who had been in the district elementary schools had already done some work with liquids and that all students brought experience and knowledge from their daily lives. To clarify the knowledge, understanding, and confusion students might have, Mr. B. prepared a set of short exercises for the opening week of the unit of study.

For the first day, he prepared two density columns: using two 1-foot-high, clear plastic cylinders, he poured in layers of corn syrup, liquid detergent, colored water, vegetable oil, baby oil, and methanol. As the students arrived, they were directed into two groups to examine the columns and discuss what they saw. After 10 minutes of conversation, Mr. B. asked the students to take out their notebooks and jot down observations and thoughts about why the different liquids separated.

When the writing ceased, Mr. B. asked, ''What did you observe? Do you have any explanations for what you see? What do you think is happening?" He took care to explain, "There are no right answers, and silence is OK. You need to think." Silence was followed by a few comments, and finally, a lively discussion ensued.

It's pretty

How do you get the colors to stay apart?

Like the ones on top are lighter or something like that.

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