I remember seeing a liquid that changes color when you shake it and then changes back to it's original color when it settles. Does anyone know what reaction this is? I would like to do it for a school project. Also, does this last forever, or will it eventually stop? If this does not work, does anyone know of anything similar that would last for a long time (like at least as a year? I am trying to make a fun interactive science exhibit for kids aged 2-12 and I though this would be cool. Thanks!