This Video Got Me A Bit Confused,

you add dry sand to water, 

then take the now wet sand out of the water and it is magically dry again! it is a kids toy called Magic sand or hydrophobic sand, it is made from sand coated with a hydrophobic compound, the presence of this hydrophobic compound causes the grains of sand to adhere to one another and form cylinders (to minimise surface area) when exposed to water, when the sand is removed from water, it is completely dry and free flowing, Magic sand is also known as Aqua Sand, these properties are achieved with ordinary beach sand, which contains tiny particles of pure silica, and exposing it to vapours of trimethylsilanol (CH3)3SiOH, an organosilicon compound, upon exposure, the trimethylsilane compound bonds to the silica particles while forming water, the exteriors of the sand grains are thus coated with hydrophobic groups, Magic sand is made in blue, green, or red in colours but appears silvery in water because of a layer of air that forms around the sand, making it unable to get wet, so a new kids toy, well it was to me but it appears it, magic sand, has a early reference to it in the 1915 book The Boy Mechanic Book 2 published by Popular Mechanics, the Boy Mechanic states waterproof sand was invented by East Indian magicians, the sand was made by mixing heated sand with melted wax, the wax would repel water when the sand was exposed to water, if you have time, definitely a 2 mug of coffee have a look at the book, it is packed with so much fun stuff, also you can make your own magic sand here.