Limestone is treated in kilns: By a chemical reaction it is transformed into quicklime.
Quicklime is needed as building material, for cement production and as an opponent of acids (agriculture and forestry). Remains of a limestone quarry and of a limestone kiln may be seen in Lauterbach. 

This experiment you must perform outdoor and together with an adult.
Do not forget your goggles, wear rubber gloves!
* Left: Put a piece of quicklime into
   an old plastic container.
* From a 5-ml syringe add as much water as the stone can suck.
* Observation right: Steam is built while the stone swells and produces enough heat to let the container melt.
* Explanation:  The stone has transformed into a powder called slaked lime. It can be used to make  mortar.