The Cool Sand Phenomenon of Boracay Island: A Comparative Study of the Thermal Properties of Philippine Beach Sands

Boracay Island is internationally recognized not only for its pristine white beaches but also for the remarkable sensation that its sands remain relatively cool even under intense tropical sunlight. Despite this well-known phenomenon, few scientific studies have investigated the thermal behavior of Boracay's beach sand using laboratory measurements. This study compared the thermal properties of Boracay white sand with beach sands from Panglao, Dakak, Pink Beach in Zamboanga, Ob-ob Black Beach in Aklan, and White Beach in Zambales. Elemental composition was determined using X-ray fluorescence (XRF), while calorimetric measurements and controlled heating experiments were conducted to evaluate specific heat capacity and heating response. Results indicate that Boracay sand possesses the highest specific heat capacity among the examined beach sands, largely due to its predominance of calcium carbonate derived from coral fragments and shells. In contrast, sands dominated by silica, volcanic minerals, and iron oxides exhibited lower specific heat capacities and warmed more rapidly under identical heating conditions. These findings provide a scientific explanation for Boracay's well-known "cool sand phenomenon" and demonstrate the influence of mineralogical composition on beach surface temperature. The study highlights the importance of preserving Boracay's unique carbonate beach ecosystem for sustainable coastal management and tourism.