How do sandcastles stay together?

Jul 23, 2023
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Interesting article - and based on the science previously known - intersticial bridging and the like but there are a few faults with some of the calculations being presented - (well known if you actually work on the beach - which I do.
The experiments quoted by scientists make assumptions based on knowledge discovered in a lab experiment under controlled conditions
The Beach is not a controlled space and conditions vary a lot!
it depends on whether you are building a castle that weighs over 50 lbs
controlled experiments using a wet granular system - what sandcastles are made of - always leaves out some fundamentals
It is a DRAINING wet granular system - there is little research on this - in fact, none
This pile of sand is also affected by
1. external air temperatures drying the sand out
2 the position and flow of the tide - sucking water away from your high tide line beach position or pushing back toward it.
3. whether you are containing the sand and water mix in a "form" or Bucket style form
4. What type of sand you have - the published assumption - saying basically all sand is the same in the way it will act when water is added is absolute nonsense and misleading.
5. The perfect mix ratio is 8:1 - where? There is no ratio on a beach - it has to be molten and contained to get consistent, repeatable results, as it is draining and you are against one thing - time
6. The only way to form consistent bonding is to make the sand anoxic in other words - use a form and mix the sand and water into sloppy wet sand and add sand to water once the base is solid.
7. Vibration on the container will give you the strongest bond possible unless there is a fractured surface to the crystals in which case artificial compaction would be helpful - but if the sand is right and contains as correctly stated, a great mix of fine granules, silt, and a little clay(natural not added) extra compaction is not needed
8. the article says that the best sand for sandcastles would be found in rivers and not on the beach as it has not eroded yet and is still sharp - there are beaches where the sand shuffles onto the beach - retaining its "sharp" qualities and other beach models the sand is rolled by very different water and tide models and corners are eroded badly hence their use for sandcastle building is diminished or not even possible - it depends on the sands journey to form the beach and the wave action on geological composition once it has formed the beach - not on how early - you find it on its long journey! - otherwise, there would be sandcastles in front of mountains! - right? (on my bucket list)
There is a common misconception that anyone can build a big sandcastle anywhere once you have squeezed some damp sand in their hand. This works to a point but for what we build- it is nowhere near accurate.

To finish - Unfortunately - most science articles on this subject have just regurgitated other articles and picked out what they think makes sense - they have never built a big sandcastle.
it is a shame that no-one wants to collaborate on a project where different beaches produce completely different results for an industry/business/location that at least 10 million people a year attend in the USA alone - THE BEACH
MORE INFO - - real consistant science!

I would have included photos but site doesn't allow uploads and image linking does not work
enjoy the beach
and remember 3 basics - Inly use wet sloppy sand - shape it like a pyramid - and work from the top down