Just how much protection do you get from hardhats and safety glasses? We're smashing watermelons and shooting bb guns to put them both to the test. Can anything stand up to a 250-pound anvil dropped from 20 feet? How hazardous is it to cut down a massive tree in your backyard? We'll learn the best tricks from a professional arborist. And when fire strikes at home, how much time is there to escape? You might be surprised how the speed of the flames is connected to the type of furniture and building materials you have at home.