Honors Physical Science

Formal Lab Report – Writing a Graphical Analysis

This demonstrates how to write a graphical analysis section of a formal lab report. Note that the analysis comments on the shape of the graph, the relationship between variables, and the mathematical formulas applied to the best fit line. You may refer back to this in the future when writing your graphical analysis.

Graphical analysis – Pi lab

The graph of Area vs. Radius appeared to be a parabola opening upward. This suggested the mathematical repationship of y = kx². Where K is a constant. To verify this relationship a second graph was plotted of Area vs. Radius².

The graph of Area vs. Radius² was a straight line. This suggested the mathematical relationship y=kx+b. Where k was the slope of the line and b was the y-intercept. Since the line passed through the point (0,0) the y-intercept was zero and the equation simplified to, y=kx. Since Area was plotted on the y axis, and Radius² was plotted on the x axis. Substituting A for y and R² for x The equation of the line was written as A = k R². Since A = π R² it was concluded that k (the slope of the line) was equal to π for this experiment. The observed value for slope was 3.0, therefore, it was concluded that π was equal to 3.0.