Back in the 70s, while adults were marvelling at the scientific breakthrough that was VHS tapes, kids were concerned with an entirely different breakthrough - though just as scientific, some would say.
We're talking about Magic Sand (also known as Mars Sand and Space Sand), of course. Now to some of us, it was a sad fact that any kind of sand was magical - especially if you lived anywhere within the M25. But for the privileged, who were quite familiar with the creative capabilities of a sandy beach or the contents of the school sand pit, Magic Sand still provoked ooohs and aaaahs aplenty. But why so magical, you may well ask?
See, your standard sand allowed you to mould it into various homages to Castle Greyskull, but when the tide came in later on, you'd watch as hours of hard work was obliterated in an instant and turned into what resembled a slurry pit. Yes, water was always sand's biggest enemy (unless you were trying to make cement)!
The genius of Magic Sand meant water was no longer a threat - this sand was waterproof! When the idea first occurred to try coating sand with a waterproof chemical, it was to aid in the cleanup of oil spills - pour a little on the surface of the water and it could make the oil descend downwards where it could later be scooped up. Eventually it found its way onto the toy scene, like many scientific experiments have done throughout the years. How does this hydrophobic sand work? Now for the science bit...
As a result of its water repellence, grains of the sand will stick to each other in the presence of water. When sprinkling grains onto the surface of water, they will at first form a 'sand raft,' until the weight of the agglomerate is large enough to break the surface tension. The mass will then sink to the bottom as a single object. When immersed, the sand forms columns in order to reduce the surface area in contact with water. These waterproof properties are achieved by covering ordinary beach sand with tiny particles of pure silica and exposing them to vapors 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.
Sold in places like Woolworths, the sand itself was sold in genie-like glass/plastic bottles, and it came in three different colours - blue, green and red - which helped it look much more like a toy. The first thing most kids did with a new bottle of Magic Sand was to throw it into a bowl of water (or the bath if Mum wasn't watching). The sand, which would take on a silvery colour underwater, would sink to the bottom and you'd be able to create sculptures underwater. Then, when you lifted the sand out of the water - and this was the truly magical bit - it was always bone dry! Paul Daniels missed a trick there!