With temperatures hitting record highs this summer, beaches—and their promise of cool ocean dips—beckon. But to reach the waves, it’s likely you’ll first have to cross an expanse of foot-scalding sand. Sand is made up of decomposed rock—quartz, mostly, but also calcite, feldspar, gypsum, or basalt, sometimes with a smattering of shell, coral, or fish poop tossed in—and according to Paul Jarvis, a geologist and volcanologist at the University of Geneva, it receives solar energy via the process of radiation. The composition of sand causes it to heat up as the day progresses and to retain that heat, reaching temperatures … Continue reading 8 Science-Backed Tips