Why Is Alaska So Cool?
(When the days are so long?)

A Series of Math and Science
Investigations in Sunlight Intensity
using Excel, Graphing Calculators and CBLs

Activity 7: Angular Intensity Investigator

Investigations in Light Intensity Change over Angular Displacement

Guiding Question:	How does the intensity of light change as the angle of incidence to the light source increases?
Description:	Students perform an experiment using a CBL light probe and TI-83 calculator to measure the light intensity from a source at increasing angles to the source. The students then plot the data and fit a sinusoidal regression equation to it on the TI-83. They plot the data in Excel and graph it, but Excel will not allow a sinusoidal regression.
Objective:	After completing this lesson, a student should be able to analyze light intensity striking a surface at varying angles of incidence.
Teaching Strategies:	Students should work in pairs to perform the experiment. The student will need the program called ANGLE loaded into their calculator. The program can be downloaded using TI-Graph Link.
Assessment:	Concluding questions are provided to measure a student’s ability to find data points on the graph, to predict new values not in the original set, and to decide which type of regression equation best models the data. The questions also ask the student to consider what affect the angle of incidence of light might have on temperatures in Alaska in the summertime.
Download:	Lesson Plans Concluding Questions Answers to Concluding Questions Sample Data Excel Graph ANGLE program