Education Technology

# Activities

• ##### Subject Area

• Math: Algebra I: Linear Functions

9-12

60 Minutes

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

TI Connect™

• ##### Accessories

CBR™/CBR 2™
TI Connectivity Cable

• ##### Other Materials
This is Activity 1 from the EXPLORATIONS Book:
Modeling Motion: High School Math Activities With The CBR

The following materials are required for this activity:
• Handful of pennies
• Paper bowl or plate
• Ring stand or hook

## Stretching a Penny

#### Activity Overview

In this activity, students investigate how a spring stretches when different weights pull on it. They relate the stretch of the spring directly to the weight and vice-versa.

#### Before the Activity

• Connect the calculator to the CBR 2™
• Install the TI Connect™ software to analyze data on the computer
• See the attached PDF file for detailed instructions for this activity
• Print pages 1 - 4 from the attached PDF file for your class
• #### During the Activity

Distribute the pages 1 - 4 to your class.

• Run the Ranger program
• Attach the plate to the spring and hang the spring from a ring stand
• Position the CBR face up under the plate
• Record the distance between the CBR and the plate
• Add 5 pennies to the plate and measure the distance between the plate and the CBR
• Repeat the above step until a total of 20 pennies have been added to the plate
• Record the distance data and calculate the amount of stretch per penny
• Add a handful of pennies to the plate, measure the distance, and predict the number of pennies
• Count the pennies and compare with the predicted value
• For a given number of pennies predict the stretch
• Determine the proportionality constant for this variation
• #### After the Activity

Students will complete the Data Collection table and answer questions listed in it.

Review student results:

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