A device for mechanically creating boom/rumble sound effects.
From http://www3.northern.edu/wild/th241/sc19.htm :
From http://www3.northern.edu/wild/th241/sc19.htm :
A thunder sheet is a large, heavy piece of sheet metal usually suspended back stage which, when shaken or hit, produces a low thunder-like rumble. The larger and heavier the sheet metal, the deeper and more substantial the effect. Northern's sheet is 4x10 feet; is approximately .024" thick (24 gauge) and weighs about 40 pounds. A small piece of "printer's tin" produces soprano thunder.
