# Activities

• • • ##### Subject Area

• Math: Algebra I: Linear Functions
• Math: PreAlgebra: Linear Functions

• ##### Author 9-12

60 Minutes

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition
• ##### Other Materials
This is Activity 3 from the EXPLORATIONS Book:
Activities for Algebra with the TI-83 Plus.

The following materials are required for this activity:
• Scale
• Wooden plank or meter stick
• Books
• Tape measure

#### Activity Overview

In this activity, students examine how moving a weight up along a board affects the downward force on the board. They explore how children with different weights can be balanced on a seesaw.

#### Before the Activity

• Position the scale and the block far enough apart so that the wooden plank is supported on one end by the scale and the other end by the block
• Starting at the edge of the scale, place marks at 10-cm increments on the wooden plank
• Set up the calculator for data collection using the procedure described in the attached Appendix PDF file
• See the attached PDF file for detailed instructions for this activity
• Print pages 23 - 34 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to your class.

• Place books at the 0 cm mark on the plank and record the weight
• Move the books to the 10 cm mark and record the weight
• Continue to move the books away from the scale in 10-cm increments and record weights
• Enter the data of distance and weight as a list
• Use this data to graph a scatter plot
• Visually estimate the trend line and find the line that contains as many points as possible
• Determine an equation for a trend line for the data, calculate the slope, and graph the trend line
• Alternatively, find a linear regression equation for the data and graph the best fit line
• Find the weight of objects placed at different distances from the scale
• Find the distance from the scale given the object's weight shown on the scale
• #### After the Activity

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

Review student results:

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