The material you will see in the in the first video below looks like and feels like regular sand. But, as you can see in this episode of BBC’s iconic quiz show QI, it sure doesn’t act like it.
The experiment starts out normally enough, with host Stephen Fry putting some red sand into a glass of water, which forms a thin, floating layer. But then he shoves his finger into the water and instead of going right through the sand, the sand forms a barrier for his skin and his finger is completely dry.
So far, so strange. But that’s not all, things get really bizarre when he adds a whole heap of blue sand, and it forms an alien – looking, congealed structure submerged at the bottom of the glass. So what do you think that will happen when he scoops some of it out with a spoon? It comes out completely untouched and dry.
It’s pretty much witchcraft, and we’re with the contestants on this one. Except it’s even better, because it’s science.
The experiment is also surprisingly simple to replicate at home. All you need is some water – repellant spray and some sand, such as Scotchgard (or gotchscard, which you’ll understand when you see the clip above). You spread the sand out and then apply few genorous coatings of water – repellant chemicals. Once it’s dry, you’re now the proud owner of hydrophobic sand.
You can also even buy hydrophobic sand, called Magic Sand, that’s pre – made, and contains tiny particles of silica mixed with ordinary beach sand. The combination is then exposed to vapours of trimethylsilanol, an organosilicon compound, that bonds to the silica particles, creating a hydrophobic coating for the sand.
Both the DIY hydrophobic variety and the Magic Sand will do anything it can to avoid contact with liquid, including forming strange formations underwater to reduce surface area.
