Education Technology

# Activities

• ##### Subject Area

• Math: Algebra II: Powers Roots and Radical Functions

9-12

60 Minutes

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition

TI Connect™

• ##### Accessories

CBL™/CBL 2™
Sensor - Light
TI Connectivity Cable
Vernier LabPro®

• ##### Other Materials
This is Activity 16 from the EXPLORATIONS Book: Real-World Math Made Easy.

The following materials are required for this activity:
• Meter Stick
• DC-powered point light source

## Light at a Distance: Distance and Light Intensity

#### 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.

• 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