4.5 Morris the Cat
Teacher's page
Software: Geometerís Sketchpad (morris.gsp)

Environment: One computer station. Students complete the student page and the graph is done with a projection device. 

Strategies: Multiple stations - students work individually, in pairs, or in small groups.

GEPA Connections: coordinate graphing, transformations, ...

The graphing of MORRIS provides insight and practice into coordinate graphing using Geometerís Sketchpad. In the process students make predictions on how changes in coordinates would change the shape of MORRIS.

The first goal of MORRIS is to plot given points and connect them to create the face of a cat. Upon completion, predictions are made as to how the face of MORRIS would change if all the (x,y)ís were subsequently replaced by (2x,2y)ís, (3x,3y)ís, (3x,y)ís, and (x,3y)ís. As each graph is created the class discusses and revisits its predictions. Would the change in coordinates enlarge MORRIS in all directions? Make him thinner? Make him taller? Make him wider?

Setting the Stage
Play the turtle hunt game (turtlehunt.mws) to make sure they know their ordered pairs. You can do this as a large group, one station activity. After that tell the students you will be using ordered pairs to make a "picture" of Morris

  1. Do the Activity

  2. Graphing Steps: 
    • Under FILE choose New Sketch 
    • Under GRAPH show axes 
    • Under GRAPH show grid
  1. Change scale by dragging the point at (1,0) along the x-axis toward the origin. This will effectively change the size of the grid. (You should create a grid that ranges from -10 to +10 on each axis if possible.)
  2. To Plot Points:
    • Under GRAPH...choose Plot Points (Use TAB to move from x to the y coordinate)
    • Click ADD and then PLOT
  1. Optional: To show coordinates on the sketch
    • Under MEASURE...Click on COORDINATES and they will appear

    • Under DISPLAY... you can hide labels, coordinates, etc. as you wish by first selecting those items you might want to hide.
5. To connect points:
    • Highlight (select) the points and then click on SEGMENT under CONSTRUCT.

Draft - revised 12.9.00

Student page
Problems page