Hold the tin up and tell the class you want to tell them a story about it.
This prospect seems so bizarre that the class turn to face you.
You'll only get one chance before somebody starts talking again, so you've got to seize it. I tell them it was a tin this size that they put the cyanide crystals in. Then I point to the ceiling of the classroom. "The tin was placed about there in a room this size", I explain. The immediacy of the comparison holds their attention.
From then on, I can tell the story of the gassing of the Jews and set the scene for my lesson on the Final Solution
For further thoughts on history teaching visit SchoolHistory.co.uk
Paul Blum teaches at Islington Green School in London