Ice bomb: Iron sphere ruptured by freezing water.

Ice bomb: An iron sphere is ruptured by freezing water. A cast-iron sphere is completely filled with water (no air). An iron plug screws into the sphere to block the hole. The sphere is placed in a metal-lined box and covered with dry ice. After 3 or 4 minutes, the water inside the sphere will freeze and expand and break the metal ice bomb with a resounding bang. NOTES: 1] Fill the bomb by submerging it in water. Tighten the plug under water so that no air can enter. 2] Instead of dry ice, a mixture of regular ice and salt can be used. It will then take about 20 minutes to break the bomb. TEMPERATURE AND EXPANSION.