Today, the children stepped into the roles of geologists to explore the fiery origins of igneous rocks. We began by investigating how magma (molten rock) from beneath the Earth's surface transforms into solid rock through cooling and the formation of crystals. The class compared intrusive igneous rocks, which cool slowly underground to form large crystals, with extrusive igneous rocks, which cool rapidly on the surface.
To see this in action, we conducted two "delicious" experiments: first, we poured a hot chocolate and coconut oil mixture over ice to mimic the instant cooling of obsidian, resulting in a smooth, glass-like finish. Next, we created "honeycomb" rock by adding bicarbonate of soda to a hot sugar syrup; as the mixture foamily solidified, it trapped gas bubbles inside, perfectly demonstrating the porous, lightweight texture of pumice. Through these hands-on models, the children successfully reported on how temperature and trapped gases dictate the appearance and physical properties of the rocks we see on Earth today.
