A new twist to an old classic! Demonstrate both linear and volume expansion and contraction with this simple device. At room temperature, the metal rod fits between the metal bracket and into the drilled-out holes. However, when the metal rod is heated, it becomes clearly visible that the rod has lengthened and swelled when it no longer fits between the metal bracket or into the holes. Reverse the process by plunging the metal bracket into ice-cold water to show the contraction of cold metal.