With the aid of a millimeter paper we were able of measuring the average diameter of each sand grain and we could observe them through an enlarger illuminated by the lamp of a smart phone.
Matteo observes the sand
Francesco observes the sand
Then we added some drops of hydrochloric acid, the bubbles deriving from CO2 was clear, this meant that after the 2002 restoration of the beach, some chalky sand was added.
Finally we weighed the whole sand and we measured the diameter of the resulting pyramid.