Water, sand, a bucket and a spade - you're set to build the castle of your dreams, complete with a moat and towers with delicate turrets. What could be more pleasant on a hot summer's day at the beach?
While most people just see it as fun, scientists are puzzled by the whole sandcastle-building experience. A team from Bournemouth University in the UK spent the summer of 2004 on the beach experimenting with various combinations of sand and water to figure out the consistency needed to create a strong structure.
They announced that the formula for the best sandy structures is: OW = 0.125 x S. Or to put it in normal English, you need one measure of water (OW) for every eight measures of sand (S) to create the perfect sandcastle-building material.
Checking the formula in other parts of the world, it seems that sand is different from beach to beach. As the size of the grains and the presence of different types of rocks and minerals create slight variations, you may need a little less water or a drop more if you plan to build your dream castle on Hung Shing Yeh this summer.
Sandcastle science in space
When you're sitting on the sand watching it flow from your bucket into a hole you've dug, it's easy to see that sand has some intriguing properties. It can be solid enough to sit on, but flow like a liquid at the same time. Add a little water and sand sticks together; add a lot, and it turns to mud.
