Education Technology

# Activities

• ##### Subject Area

• Math: Algebra I: Linear Functions

6-8

60 Minutes

• ##### Device
• TI-73 Explorer™
• ##### Other Materials
This is Activity 10 from the EXPLORATIONS Book:
Activities for Algebra with the TI-73.

The following materials are required for this activity:
• Paper cups or film containers
• Marbles, pennies, and other small objects
• Paper clips
• Meter stick

## That's a Stretch

#### Activity Overview

Students determine the relationship between the stretch of a spring and the number of weights in a cup suspended from the spring. They find the Y-value of a function if the X-value is provided. They use technology to plot a set of ordered pairs and to find a best fit line.

#### Before the Activity

• Place the slinky on the center of a meter stick at a certain height above the floor, and hang the cup on the slinky
• Set up the calculator for data collection
• See the attached PDF file for detailed instructions for this activity
• Print pages 133 - 145 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to the class.

• Measure and record the distance from the cup to the floor
• Add 5 marbles (or any small object) to the cup and measure and record the distance from the cup to the floor
• Continue adding marbles in increments of five and record data
• Enter the number of objects and the distance as a list
• Set up a scatter plot and find the equation for the number of objects versus the length of the slinky
• Find the y-intercept, and determine the slope
• Find a best fit line, graph it, and record its slope
• Compare the stretch for different objects
• Determine the stretch for a given number of the same objects, and the number of objects given the stretch
• #### After the Activity

Students will complete the Data Collection and Analysis page and answer questions.

Review student results:

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