Even though drowning in quicksand is not as popular in the movies anymore, it still remains an object of fascination. How does it work? Daniel Bonn, a scientist travelling in Iran took home a sample to analyse and his findings were quite interesting…

He found it consisted of sand, water, salt and clay. These ingredients form a structure with large water-filled gaps between sand particles, glued in place with clay. Almost like a house of cards.

If this structure is disturbed by stepping on it, the clay changes from a jelly-like consistency to runny. The sand part sinks to the bottom and the water floats to the top. Because of the salt in the water, the clay particles become electrically charged, forming bigger particles that also settle with the sand.

In the end you have a stodgy layer of sand and clay twice as dense as the original with you packed tightly in the middle. Bit of a problematic situation, isn’t it?!

Source: Naked Scientist