These days, beach-goers use coconut oil to achieve a tan, but milk spray was briefly hailed in the 1930s as a sun bather's best friend. Developed in Glendale, CA, milk spray machines used motor-driven atomizers to spritz people with a sheer coat of solution. Supposedly, milk would prevent sunburn while helping beach-goers toast themselves to the perfect shade of brown.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.