When you first open the play dough tubs, each color is neatly separated. But after a while, little bits (or sometimes big bits) get mixed together, leaving you with an ugly lump of all sorts of random colors, heading towards a sort of jungle-river brown.

If each color of dough were a different density just slightly higher than that of water, you could just dump the whole mess in a bucket of water. The different colors would settle out into different layers, and you could scrape them out, squish out the excess water, and you're back to nicely partitioned colors again!
-- snoyes, Nov 17 2008

The trouble is that the different coloured lumps are already stuck together in the ball. Putting the whole thing in water wouldn't unstick them, the whole ball would sink in it's current mixed state. [+] for addressing the problem though
-- Mony a Mickle, Nov 18 2008


If water won't separate the colours, put the lump in a high speed centrifuge. [+]
-- Wrongfellow, Nov 18 2008


Ooh, how 'bout specific density thixotropic playdough?
It would retain a squishable consistancy but act as a liquid when vibrated and separate into layers.
If perforated disks with densities between those of each color were added to the mix while it vibrated then separation of each color after the vibration had ceased would be a breeze.
-- 2 fries shy of a happy meal, Nov 18 2008


Clay turns into sludge and settles to the bottom when you put it in water. That sludge is about as unstuck as you get. After a day or so you can pour most of the clear water off the top, pour the sludge out on a large surface, and a while later you have nice workable clay again.

If playdough behaves the same way, the different colors would separate nicely if they had different densities. I'll go try it.
-- snoyes, Nov 18 2008



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