Education Technology

# Activities

• ##### Subject Area

• Math: Algebra II: Trigonometric Functions

9-12

60 Minutes

• ##### Device
• TI-73 Explorer™
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition

TI Connect™

• ##### Accessories

CBL™/CBL 2™
Sensor - Light
TI Connectivity Cable
Unit-to-Unit link cables
Vernier LabPro®

• ##### Other Materials
This is Activity 24 from the EXPLORATIONS Book:
Real-World Math Made Easy.

The following things are required for this activity :
• Fluorescent light

## Lights Out: Periodic Phenomena

#### Activity Overview

In this activity, students will use a light sensor to collect intensity data for fast and slow variations of intensities. They will then describe these variations using the concepts of period and frequency.

#### 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 237 - 243 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to your class.

Follow the Activity procedures:

Method 1:

• Point the sensor toward a light source and begin data collection
• Use the thumb to cover and uncover the light sensor at one-covering-per-second rate
• Observe the graph of light intensity versus time
• Determine the period and frequency of the cover-uncover function

• Method 2:
• Point the sensor toward a fluorescent light source and recorded intensity every 0.0005 seconds
• Examine the light intensity versus time plot
• Determine the period and frequency of the pattern from the fluorescent light
• Model the data using an absolute value sinusoidal equation
• calculate the flicker frequency
• #### After the Activity

Students will analyze the data and fill in the Data Collection and Analysis Sheet. They also 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