Education Technology

Light at a Distance: Distance and Light Intensity

Published on 07/02/2009

Activity Overview

In this activity, students will use a light sensor to record the light intensity at various distances from a bulb. They will compare the data to an inverse square and a power law model.

Before the Activity

  • Connect the light sensor to Channel 1 on the CBL 2™ or Vernier LabPro®
  • Connect the CBL 2 or LabPro to the calculator using the Unit-to-Unit cable
  • See the attached PDF file for detailed instructions for this activity
  • Print pages 157 - 162 from the attached PDF file for your class
  • During the Activity

    Distribute the pages to your class.

    Follow the Activity procedures:

  • Arrange the sensor and the light bulb for data collection
  • Dim the lights to darken the room
  • Move the sensor away from the light source in 1 cm increments and study the graph of light intensity versus distance
  • Trace the graph, record the left-most x and y values on the Data sheet, and calculate the initial model parameter
  • Use these values to model a best fit function for the inverse-square model and the power law model
  • After the Activity

    Students will complete the Student Data Collection and Analysis Sheet and answer the questions listed in it.

    Review student results

  • As a class, discuss questions that appeared to be more challenging
  • Re-teach concepts as necessary