How to Draw an Ellipse

How to Draw an Ellipse Did your math teacher confuse you when he or she introduced an ellipse (I dont mean an elliptical trainer here.)? Well, she has probably given the definition of an ellipse to you first. Perhaps, her words sounded like this. An ellipse is a curve on a plane surrounding two focal points such that a straight line drawn from one of the focal points to any point on the curve and then back to the other focal point has the same length for every point on the curve. While I think definitions are important they are often not a good way to start explaining a concept. Therefore, lets take a look at Saturns rings first: From the way we see them on Earth they form an ellipse. Loosely spoken they are an elongated circle in the shaped of an egg. How can one draw an ellipse? First, set up two points on paper. These two points form the foci of our ellipse. Next, connect these two points by a string longer than the distance between these points. Take a pen and move it along the stretched string. The path your pen moves precisely forms an ellipse. This animated picture visualizes the process. Ellipses are common in physics, astronomy and engineering. In 1609 the German mathematician Johannes Kepler famously proclaimed that the orbit of a plan of planets is an ellipse with the Sun at one of the two foci. Keplers discovery has been hugely influential in both the proliferation of the helio-centric model back then and space flight today.