In mathematics, a parabola is a plane curve which is mirror-symmetrical and is approximately U-shaped. It fits several other superficially different mathematical descriptions, which can all be proved to define precisely the same curves. One description of a parabola involves a point and a line. When the liquid is rotated, the forces of gravity result in the liquid forming a parabola-like shape. The most common example is when you stir up orange juice in a glass by rotating it round its axis. Parabolas are also used in satellite dishes to help reflect signals that then go to a receiver.