An Archimedean spiral is a type of spiral that expands outward at a constant rate. It is defined mathematically by the equation r = a + b\theta , where r is the distance from the center, \theta is the angle, and a and b are constants. This means that as the angle increases, the distance from the center increases linearly, creating a spiral shape. These spirals are named after the ancient Greek mathematician Archimedes, who studied their properties. Archimedean spirals can be found in various natural and man-made structures, such as in the arrangement of seeds in a sunflower or in certain types of shells.