The Catherine wheel or pinwheel is a type of firework consisting either of a powder-filled spiral tube, or an angled rocket mounted with a pin through its center. When ignited, the energy of the fireworks not only create sparks and flame, but cause the wheel to quickly rotate, making the display much more spectacular. The physics of the process are those of an aeolipile. The firework is named after Saint Catherine of Alexandria who, according to Christian tradition, was condemned to death by “breaking on the wheel”. When she touched the wheel it miraculously fell to pieces.