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 3:  Diameter Detective and Area Analyzer

 

Collecting Data on the Diameter and Area of Circles
and Fitting with Linear and Quadratic Equations

 

 

Guiding Question:

 

How do the diameter and area of circles of light change in relationship to the distance from the light source?

 

Description:

In this activity, the students perform an experiment to collect data about diameters and areas of the circles of light produced from a flashlight as the distance from the light source increases. The students should discover that the change in diameters is a linear relationship and the change in areas is a quadratic relationship.

 

Objective:

To find the diameters and areas of circles of light formed by a flashlight at given distances from the light source.

 

Teaching Strategies:

Pairs or groups of students can perform the experiment. The smaller the flashlight, the more data can be collected on a small piece of paper as the circles of light grow quickly. It may be easier to draw the circles on graph paper attached to a wall since the surface will be stable.

 

Assessment:

Concluding questions ask students to determine the type of best-fit regression equation, to explain what the coefficients of the equation represent, to predict new values of data not in the original set. An Excel graph of sample data is also provided.

 

Download:

Lesson Plans (Word)

Concluding Questions (Word)

Answers to Concluding Questions (Word)

Sample Data Excel Graph (Excel)

Behavior of Light (Word)

Discussion of Quadratic Equations