`Circles MinilabAlan L. Tobecksen              Henry Clay Elementary School                               13231 Burley                               Chicago IL 60633                               (312)535-5600Objectives:Parts of this experiment are suitable for third grade through sixth grade, but the intended grade level is seventh through high school.1. Students will practice measuring in the metric system.2. Students will learn to gather and organize data.3. Students will practice graphing simple data.4. Students will draw the inference that the slope of the line is pi.Materials Needed:Each group of 2 to 4 students will need6 to 10 assorted circular lids (jars, milk containers, coffee cans, etc.)meter stick30cm length of stringgraph paperpaper to write on to organize the dataStrategy:Each group measures the diameter and circumference of each lid in their collection.  The diameter is measured directly by placing the meter stick across the center; the circumference is measured by wrapping the string around the outside and then measuring the string.  The group recorder makes note of the data as each lid is measured.  The group then makes a graph of their data ploting diameter on the x-axis and circumference on the y-axis and, hopefully, recognizes that the slope of the line is pi.  It is also suggested that a simple calculation of dividing the circumference by the diameter be made by the students for each lid. Performance Assessment:Subjective: The teacher should observe the students to be sure that the measurements are being done correctly and that data is being gathered and organized.Objective: The data table and graph can be given a grade.Conclusions: Students from fourth grade through high school should be able to do most, if not all, of the exercise.References:Merrill Physics - Teacher Guide`