Education Technology

Mapping a Leaf

Published on 06/09/2008

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.

    Follow the Activity procedures:

  • 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