1 Discard any hammer with mushroomed or chipped face or with cracks in the claw or eye sections. 2  Wear safety glasses or goggles, or a face shield (with safety glasses or goggles).  Strike a hammer blow squarely with the striking face parallel to the surface being struck.
The first jet airplane was the Heinkel He 178 made in Germany in 1939, right before the outbreak of World War II .
On this day in 1903, near Kitty Hawk, North Carolina, Orville and Wilbur Wright make the first successful flight in history of a self-propelled, heavier-than-air aircraft. Orville piloted the gasoline-powered, propeller-driven biplane, which stayed aloft for 12 seconds and covered 120 feet on its inaugural flight.