Although not inquiry, this activity is important for students to understand what an ellipse is and what a focus is, and to break misconceptions about Earth’s orbit being highly elliptical. This is the perfect place to check to see if students have the misconception that the seasons are caused by the distance between the Earth and the Sun. Ask “What causes the seasons?” and most students will respond that summer is when the Earth is closest to the Sun in its highly elliptical orbit. If they see that the orbit is nearly a perfect circle, they will understand that this cannot be true.