Lesson 1

Introduction to Conics

Purpose

After completing this exercise, students will be able to determine which conic section comes from a specific cut of the cone and identify examples of these curves from magazines, newspapers, and Internet resources.  This purpose is to show that this topic does relate to the real world and hopefully engage students in the process of studying the physical properties of these unique curves.  For real world examples of conic sections click here

This activity comes from Lesson Plan 3 Conic Sections by Virginia Laird, Rockwell High School, Richardson, Texas

Materials

Play-do, string, markers, tape, large paper, magazines, newspapers, and Internet access.

Activity

1.                  Divide students into groups.

2.                  Have students within each group form a cone using Play-Do.  Have students slice the individual cones using the string through the cone parallel to the base and perpendicular to an imaginary line through the center of the cone.  Trace the result on a large piece of paper and then choose a real world object that resembles the curve that they just found, a circle.

3.                  Reshape the cone and then slice the cone at an angle to the imaginary axis, but not through the base of the cone.  Trace the ellipse and find real world examples.

4.                  Cut a third slice by placing two cones nose to nose and then slicing from the base of one cone parallel to the imaginary axis and through both cones to the base of the second cone.  Draw the resulting hyperbola and find real world examples.

5.                  The final cut is made by slicing parallel to an imaginary line on the side of the cone and passing through the base of the cone. Draw the parabola and find real world examples.