Conic Sections
Conic Sections started out as a Geometric Concept. Start
with a right circular cone from Geometry. Create a "double cone"
as shown below, and "slice" the cone four ways.
("Slicing" is the intersection of a cone and a plane.)

The intersection of a cone and a plane parallel to the
circular base is a circle.


The intersection of a cone and a plane not parallel to the
circular base but intersects both sides of the cone is an ellipse.


The intersection of a cone and a plane not parallel to the
circular base that intersects one side of the cone is an parabola.


The intersection of a cone and a plane perpendicular to the
circular base creates the branches of a hyperbola.



Circle

Ellipse

Parabola 
Hyperbola 
Flashlight Conic Sections
The light emitted from a flashlight with a circular lens is
projected as a cone from the light bulb. You can create Flashlight Conic
Sections by projecting the light at the wall, allowing the wall to be the plane
and the light from the flashlight being the cone. Try the following
shapes:
Flashlight Circle 
Flashlight Ellipse 
Flashlight Parabola 
Flashlight Hyperbola 
