How many Bunsens are alight in this picture? Two?
Wrong! Only one. The other is a ghost flame caused by a trick of the light. The Perspex sheet in front of Tom reflects the light from the Burner so we see its reflection in the almost invisible Perspex. It looks like Tom’s is really brave and can swipe his hand through the fire without getting hurt. This is an illusion first used in the theatre by Mr Peppard to make ghosts appear on stage. Clever!