Lesson 3: Polygons and Parameters - Instructor's Notes

This page contains some tips and suggestions for the instructor when presenting lesson 3.

Lesson Goals

The goal of this lesson is for the children to:

  1. Learn how to create procedures that take parameters.
  2. Learn why parameters are useful.
  3. Learn about regular polygons.

Lesson 2 Review

Ask the following questions to remind the children of what the learned in the previous lesson.

Formal Presentation

The "big idea" in this lesson is that procedures can take parameters and that the parameter can change what the procedure does in useful ways.

Ask the question "what is the procedure for drawing a square" and write the answer on the blackboard. Now ask "what is the procedure for drawing a triangle" and write the answer on the blackboard. Do the same thing for a pentagon and a hexagon (you may have to tell the children what those shapes are).

At The Computer

Once all the procedures are on the blackboard, ask the children if they see a pattern. Then show them how to make a single routine that does all of those shapes (and others). Once you have defined the routine, let the children enter it into the computer and try different numbers. Ask what happens when the number is smaller than 3. Ask what happens when the number gets very large.

Finally, challenge the children to generalize the program again so that it can draw polygons of different sizes.