Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Transformational Geometry

6-8

60 Minutes

• ##### Device
• TI-73 Explorer™

TI Connect™

• ##### Accessories

TI Connectivity Cable

• ##### Other Materials
This is Activity 6 from the EXPLORATIONS Book:
Data Collection Activities for the Middle Grades with the TI-73, CBL™, and CBR™

The following materials are required for this activity:
• Grid paper
• Marking instrument like pen
• A leafy twig
• Pin or tape

## Mapping a Leaf

#### Activity Overview

In this activity, students will identify and record ordered pairs from a coordinate plane. They will examine symmetry about the axes, reflections, and symmetry in nature. They understand geometric concepts like area and perimeter, and various types of transformations.

#### Before the Activity

• Install the TI Connect™ or TI-GRAPH LINK™ software on the TI-73 using the TI Connectivity cable and the unit-to-unit link cable
• See the attached PDF file for detailed instructions for this activity
• Print pages 91 - 101 from the attached PDF file for your class
• #### During the Activity

Distribute the pages to your class.

• Place a big leaf on a grid paper such that its base is on the origin
• Mark a point at the end of the stalk (petiole) and where the flat portion (blade) starts
• Continue to mark points that represent the perimeter of the leaf
• Transfer the coordinates of these points to a list with x and y values
• Plot a graph of the points to see the outline of the leaf
• Create a reflection on the y-axis and generate a list of new x- values
• Plot the points to view the reflected leaf
• Two leaves (opposite) at the same node on the stem show such reflection
• Model alternate type of leaves (offset on the stem) by translating the values on the y-axis up
• To plot the third leaf on the stem, use the original x and y values and increase the y-values by the number that represents the distance between the nodes
• Save the plot with the leaves
• #### After the Activity

Students will fill in the Student Data Collection and Analysis Sheet.

Review student results:

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