At a recent science demo exhibit my daughters were introduced to hydrophobic sand. Hydrophobic sand, often called 'magic sand', looks like regular sand, but it's coated with a substance that repels water. Thus the name hydrophobic (afraid of water). Hydrophobic sand is cool to play with since it doesn't react the same as regular sand. Here's a video of me playing in the sand. :-)
Another cool demo with hydrophobic sand is to take a tank of water and sprinkle hydrophobic sand on the water's surface. Then stick your finger in the water. It doesn't get wet! The hydrophobic sand repels the water from your finger. You can also mess around with it on a spoon, as seen in the video below, once again, of me playing with it. :-) The video shows a bubble of water coated in sand.
You can get some of your own hydrophobic sand to play with. Do a search on Amazon and you'll find plenty of purchasing options. Very cool stuff!