Scientists Say: Ellipse

An engraving from the 1888 book Nouveau Dictionnaire shows how the Earth's elliptical, or oval-shaped, orbit around the sun explains astronomical concepts such as the summer and winter solstices and spring and autumn equinoxes.

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Ellipse, (noun, “Ee-LIPS”)

Ellipse is a mathematical term for a type of oval shape. This shape looks like a squashed circle. The exercise machine called an elliptical gets its name from the elliptical shape you make when pedaling. Earth and other planets in the solar system follow ellipse-shaped paths as they orbit around the sun.

This ellipse has the two focal points A and B. At each point along the ellipse, the distance from that point to A and the distance from that point to B, added together, will always be the same.Made with GeoGebra by M. Temming

An ellipse is defined by the location of two points inside the ellipse. These are called the focal points. At each point along an ellipse, the combined distances to the two focal points is the same. A circle is a type of ellipse where the two focal points are stacked on top of each other. When the two focal points are farther apart, you will have a narrower, longer ellipse. Bringing them closer together makes a wider, more circular ellipse.

In architecture, ellipse-shaped rooms can feature some wacky acoustics. Often called “whispering chambers,” you can stand at one focal point and hear far-away whispers from the other focal point. One famous example is the National Statuary Hall in Washington, D.C. There’s a bronze plaque marking where John Quincy Adams’ desk was. (Adams was the sixth president of the United States.) If you stand where his desk stood, you can hear whispers from across the room. Renovations to the room’s domed ceiling have likely altered the acoustics since John Quincy Adams’ time. But the phenomenon still gave rise to legends that he used to eavesdrop on other politicians.

In a sentence

In 2017, teen engineers developed an improved wing-shape for drones by swapping some of the elliptical-shaped wing curve for a bell-shape.

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Katie Grace Carpenter is a science writer and curriculum developer, with degrees in biology and biogeochemistry. She also writes science fiction and creates science videos. Katie lives in the U.S. but also spends time in Sweden with her husband, who’s a chef.

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