Iron is stronger than ice, right? Not on a cold winter's day. Vividly demonstrate what happens to water when it freezes-it expands with enough force to crack a cast iron pipe! Immerse a completely water-filled cast iron pipe into a dry ice/ethyl alcohol bath. Allow it to cool for several minutes. When the water freezes to a solid inside the pipe-BANG!-the iron pipe cracks to reveal the solid ice. Enough materials to perform the demonstration twice. Dry ice and 95% ethyl alcohol not included. Teacher Demonstration Notes included.