Building sandcastles is one of the fundamental joys in life, irrespective of how old you get. While coastal residents can hop down to play by the ocean any time, landlocked adventurers need to get a bit more creative. Enter Moon Dust, a quick and cheap recipe for sticky sand.
Moon Dust is sticky enough to hold pressed forms. Photography credit: Andrea Paterson
Poking around the kitchen is a great way to invent a messy, fun toy for summer science adventures. You're probably familiar with Dr. Suess's oobleck, a pressure-sensitive mix of cornstarch and water, but have you tried the sticky-silky mix of flour and oil?
Mix flour and baby oil in the right proportions, and you have a cheap, fun toy of sensory delight. The recipe calls for 9 cups of flour to 1 1/4 cup of baby oil, which works out to to a 36:5 by-volume ratio. You could stick to the same proportions in a smaller batch by using 2 1/4 cups of flour to 5 tablespoons of baby oil. The flour makes for silky-smooth texture reminiscent of the super-fine powdered dust on the moon.
Pack Moon Dust into a cup, invert, and you've got the start of a castle. Photography credit: Andrea Paterson
The real question is, is it fun? I loved it, but I needed to borrow a child for a true performance test. Andrea mixed a batch up to play with her adventurous lad, took a lot of photos, and reported back:
So the moon sand was a huge success. My analysis is that it definitely has the texture and properties of wet sand. It's perfect for making sand castle type structures and it crumbles back into a sandy texture if you break it apart with your hands. However, it was way messier than I anticipated. It got all over our clothes and we had to hose down our entire patio afterwards. It was tons of fun though, super easy and cheap to make, and has a ridiculously lovely silky feel when you play with it.
Playtesting confirms that Moon Dust is messy, fun, and didn't maim the test-child. Success! Photography credit: Andrea Paterson
For variations on the theme, try adding colour with a bit of powdered tempera paint, sparkle with some glitter, or drop the temperature by storing the mix in the freezer until playtime. If you feel like tempting the "Don't eat that!" gremlins, you can even make it smelly with kool-aid powder (also making it colourful) or a few drops of a flavour extract. If you don't have the requested ingredients, try substituting 4 parts cornstarch to 1 part vegetable oil.
You can even mix Moon Dust with Oobleck for something closer to the texture of wet beach sand. Traditionally goopey Oobleck, the non-Newtonian fluid inspired by Dr. Seuss's Bartholomew and the Oobleck, uses a 2:1 mix of cornstarch and water to make a drippy material that dries and hardens when you apply pressure. You can make a cross between it and the silky Moon Dust by adding sand. Keep the same proportions, but add twice as much sand as cornstarch. The 4:2:1 proportions (4 cups sand, 2 cups cornstarch, 1 cup water) make a weird hybrid that is fascinating to drip and poke on a lazy summer evening.