Can high pitched singing really shatter glass? Our duo enlists the help of an opera singer before heading to a firing range to test the true resistance of bullet-proof glass. Also, find out about Bumper Harris, the one-legged man employed to travel on escalators in Edwardian London to demonstrate ease of usage. In ‘Testing Testing’ meet Sid the mannequin who is blasted daily with 1,000C flames to test fireproof clothing. Then Jonny takes an angle grinder to a snooker ball to see what’s inside and we go behind the scenes at a soap factory.