Circles Minilab

Alan L. Tobecksen              Henry Clay Elementary School
                               13231 Burley
                               Chicago IL 60633
                               (312)535-5600

Objectives:

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 need
6 to 10 assorted circular lids (jars, milk containers, coffee cans, etc.)
meter stick
30cm length of string
graph paper
paper to write on to organize the data

Strategy:

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