[O-08] Poster presentations by senior high school students

[O08-P66] Starfish Chalk - Explore the characteristics of chalk using starfish -

*Shunta Kanno¹, *Ryoma Yamada¹, Kazumi Igawa¹ (1.Zushi Kaisei Senior High School in Kanagawa)

Keywords:Sea

We have been researching starfish. Now, damage to fisheries is happening in many places due to massive outbreaks affecting starfish (mainly sand sifting starfish, spiny sand seastars, and Northern pacific seastars). These starfish are being exterminated in large quantities. They are used as compost or repellents, but most of them are simply discarded. Therefore , we examined if there is a way to put these discarded starfish to good use. We knew that starfish skeletons and outer crusts are composed of calcium carbonate (CaCO3). We thought of making chalk from starfish (hereafter, referred to as starfish chalk). We researched chalk, but we couldn’t find any existing starfish chalk. We wondered why nobody had made any, so we made chalk not only of starfish, but also manila clams and Yesso scallops in order to analyze starfish chalk, its demerits and merits. This is the purpose of this study. The experimental method(based on a commercially available chalk- making kit) involves heating and then crushing starfish into a powder, mixing the powder with PVA and water, molding it, and allowing it to dry for several days.