Featured in PASCO’s Physics through Inquiry Teacher Guide

Physics through Inquiry Teacher Guide

(PS-2873C)

Features over 30 inquiry based labs covering the core topic areas of mechanics, electricity and magnetism, optics, thermodynamics and more.

Inverse Square Law

Lab Summary

Use a light sensor to experience the concept of light intensity varying inversely as the square of the distance from a point source of light.

Theory

During the course of this lab, students have the opportunity to actually experience the concept of light intensity varying inversely as the square of the distance from a point source of light. All of the textbook illustrations that show how and why this law works will become a real-time experience for those who complete this experiment. The experiment will provide first-hand experience in the following areas:

  • Using relevant technology (in this case a light sensor) to investigate the concept of the inverse square law of light intensity.
  • Analyzing and drawing inferences from a graph of “Light Intensity versus Distance” that was collected with real data during the experiment.
  • Comparing the theoretical model (the one taught in the textbooks) to the actual mathematical model (the one that they collect in the lab.) concerning this Inverse Square law.

Method

Students gain experience conducting the following procedures:

  • Simultaneously measuring light intensity and distance from a point light source.
  • Collecting data using the “Manual Data Collection” mode.
  • Graphing one measured quantity against another (in this case, light intensity vs. distance).
  • Linearizing a graph.
  • Drawing conclusions from graphed data. (Making the actual graph fit a mathematical model).

Sensors / Equipment Used:

PASPORT Light Sensor

(PS-2106A)

Features a wide measurable range by offering three light ranges accommodating various different measurement situations. For use with PASPORT Interfaces.

PASPORT Sensor Extension Cable

(PS-2500)

Allows an additional two meter length extension on all PASPORT sensors.

Materials Used:

Basic optics bench

Basic optics light source

Basic optics Aperture bracket

The Associated Bundle:

Physics Standard Sensor Bundle

(PS-2931B)

Contains the probeware needed to perform all 37 lab activities in the Physics through Inquiry lab manual.

Interface Required

This experiment may require software and an interface for data collection.