Name Section Date Lab 3 Experimental determination of

Name_______________ Section_______ Date_______ Lab #3 Experimental determination of pi, part 1 (part 2 will be next week) Purpose: The relation between a circle’s circumference and diameter (1) Print out this lab and cut out the paper ruler on the second page (2) Carefully use this ruler to measure the circumference (distance around the perimeter of the circle) and the diameter of each of the circles on page 3. Record your data in the table at the bottom of page 4. The pictures below show what a circumference measurement might look like. Alternatively, you can wrap a length of string along the circumference of the circle and then straighten out and measure the string. (3) On page 4 of this lab, plot the diameter on the X-axis and the circumference on the Y-axis for each circle. (4) Using a rigid straightedge, draw a single straight best fit line through as many of the points as possible. You need not cross through every point. Here is a sample of what this might look like: (5) Notice since we did not measure or plot the origin (0, 0) our best fit line did not pass though it. That’s alright. Also notice we did NOT “connect the dots”. We’re interested in the single valued slope of this line and not a series of line segments. Do NOT connect the dots. (6) Lastly, circle two points on the line (NOT ones that you have plotted) and determine the (x, y) coordinates of theses points. Write the numerical values for x 1 y 1 and x 2 y 2 on the graph paper beside each circled point. See here (x 2 , y 2) (x 1 , y 1) (7) This concludes part 1 of this lab. Submit only the graph with the table below to your lab teacher (page 4). Make sure you have written your name on top. Don’t lose this sheet. We’ll be using it next week. Write the numerical values for each coordinate

Name_______________ Section_______ Date_______ Circumference vs. diameter for 4 different sized circles 70 Circumference (centimeters) 60 50 40 30 20 10 5 Circle number Circle 1 Circle 2 Circle 3 Circle 4 15 10 Diameter (centimeters) Diameter in cm (X-axis) 20 25 Circumference in cm (Y-axis)