@misc{oai:repo.qst.go.jp:00069907,
 author = {関根, 絵美子 and 安西, 和紀 and 関根 絵美子 and 安西 和紀},
 month = {Oct},
 note = {Purpose
Buoyancy and gravity disappear in the condition of weightlessness. We observed the behavior of ping-pong ball and iron ball, placed in a water-filled acrylic box, in the micro-gravity. The purpose of this study is to make teaching materials for the primary and secondary students to understand weightlessness.
Materials and methods
We designed a device made of the acrylic box which sealed up ping-pong ball and iron ball under water. Under the gravity (1 G) and in the water, the ping-pong ball float and the iron ball sink. When the condition became micro-gravity, I reversed the container, and observed the behavior of both balls using by a video tape recorder. The condition of micro gravity was produced by parabolic flight of a jet.    
Results
When the condition approached micro-gravity by parabolic flight, the ping-pong ball and the iron ball sunk and/or floated, and this phenomenon was repeated during micro-gravity interval. The device was reversed when the weightlessness became stable (Hi call) . After iron ball sunk and ping-pong ball floated, both balls were sunk slowly . Then, both balls sunk and/or floated and repeated. These results suggested that the both balls float/sunk according to vibration of the micro-gravity. This system seems to work as a sensitive micro-gravity detector., 日本マイクログラビティ応用学会},
 title = {無重力状態の水中でピンポン玉と鉄球の位置関係が変わったらどうなるか？},
 year = {2009}
}