In 7th grade Inorganic Chemistry, they took their classroom to the garden to observe the Lime Cycle. They prepared the lime kiln for firing the marble or calcium carbonate. Next, the students layered charcoal and marble, and they fired up the kiln. At the end of the day, they revisited the kiln to observe the firing and the transformation of calcium carbonate into calcium oxide or quick-lime. When water was added, it steamed and fizzled, and it became calcium hydroxide or slaked lime. In these demonstrations, the students observed the transformation from one state to another. The hard marble became dried out and crumbly in the burning process. When water was added, a transformation took place, and putty was created. When sand was added to the putty, the substance hardened again to form cement. The Lime Cycle came full circle.
