Pluronic is an ABA tri-block co-polymer, meaning that it has three regions of repeating chemical units, and the outer two are the same. When it's above a critical temperature, it collapses into a micelle with the out part forming a protective ball around the inner part. These micelles form a network and behave like a gel, but if the temperature is lowered it reverts back to a liquid, sort of like an re-un-boilable egg.
|This image cannibalized from a google image search for pluronic.|
When I dropped the dry ice in the pluronic, it landed on top of the gel and quickly cooled the region immediately below it, turning it liquid. This wave of cold slowly propagated downward, liquifying the gel in the process. Gravity gradually brought the ice pellet towards the bottom as it cleared out its own passage downward.
|The slow but inexorable pull of gravity brings the dry ice pellet down to the bottom of the vial as it clears its own path via a wave of liquefied gel. This is easier to see in the stabilized video.|
|That's what's up.|
So during this process, we had gel, liquid, gas, and two kinds of ice. Science is cool!