Qualitative Modelling the Dancing Volvox with Two-Body System: Comparing Simple Mechanics with Observation Video
Sevi Nurafni (a*), Septian Ulan Dini (a), Intan Taufik (b), Sparisoma Viridi (a)

a) Faculty of Mathematics and Natural Science, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia
*sevinurafni54[at]gmail.com
b) School of Life Science and Technology, Institut Teknologi Bandung, Jalan Ganesha 10, Bandung 40132, Indonesia

Abstract

Volvox cells normally construct a spherical colony of hundred of cells and moving together to perform their basic needs. More than moving a single colony, two attached Volvox colonies can dance and move together. This system can be modeled as a two-body system, where its center of mass (COM) is performing simple translation(TRAN) motion, while the two colonies center is rotating around the COM with roll (ROLL) or spin (SPIN) motions. From the available observation video, about 10 s or 300 frames can be isolated to get a clear picture of the dancing motion of two Volvox colonies. It has been observed that the dancing Volvox has a superposition motion of the other motion (TRAN, ROLL, SPIN), which has been compared qualitatively with the simple mechanics model of the two-body system. From the model, the translation velocity is about 1.25, and its roll and spin angular velocity are about 0.785 and 3.063, respectively.

Keywords: dancing volvox, mechanics, two-body system, qualitative model

Topic: Modelling and Computational Physics