Drawing an Ellipse: Two Toothpicks and a Pen

The planets that orbit our star, the sun, travel in an _______________ orbit. If you filled in the blank with elliptical, you're right. An ellipse has __________ focus points while a circle only has ________. If you placed two in the first blank and one in the second blank, you're right again. This video shows you how to draw an ellipse. Try it yourself! If you demonstrate it to the class you can earn 5 extra credit points!

What points do the two toothpicks represent in this video? If you answered "the two foci" or something like that, you would be right. A circle could be made with one toothpick. An ellipse needs two. Why? Because it has two focus points. What is one of the focus points of Earth's orbit? If you answered "the Sun", you'd be right.