Analog experiments on formation process of "Pele's hair" and "Pele's tears" using a cotton candy machine

"Pele's tears" and "Pele's hairs" are volcanic glass products, which are observed in Hawaii Islands. They are formed by breakup, stretching, and cooling of molten magma during their eruption. Their formation process is complicated, and the morphology depends on many parameters such as rheological properties of the volcanic glass, cooling rate, ejection speed, wind velocity, and so on. To understand the formation process of "Pele's tears" and "Pele's hairs", we have conducted analog experiments using a handmade cotton candy maker. The experimental equipment consists of a rotating dish, a heater, and measurement system of temperature and rotation velocity. The rotating dish is made of thin steel and has small outlets along its periphery. To make threads of cotton candy, the crystal sugar is added to the dish, and rotated at a constant speed. The melted sugar (the analogue of molten magma) was formed after heating the rotating disk and ejected through the outlets at its periphery. The flow behavior of the melted sugar jet was captured by a high-speed video camera, which helped us to understand the formation process. The rotating speed, heating temperature, and diameter of the outlets cause a variation in the texture of the cotton candy. We have succeeded in producing similar texture of "Pele's hair", and if you taste them you will enjoy the texture of the analogue Pele's products. In this presentation, we'll also discuss how the difference in morphology between "tear" and "hair" occurs.