* Chemical Reactions: Stalagmites form through a series of chemical reactions.

* Dissolution: Rainwater, naturally acidic due to dissolved carbon dioxide, dissolves calcium carbonate (limestone) in the cave ceiling.

* Precipitation: As the water drips from the ceiling, the dissolved carbon dioxide escapes back into the air. This causes calcium carbonate to precipitate out of the water, forming stalactites hanging from the ceiling.

* Growth: Over time, the drips from the stalactites fall to the cave floor, where they continue to precipitate calcium carbonate, building up the stalagmite.

* New Substance: The original calcium carbonate in the limestone is converted into a new substance, calcium carbonate in the form of stalagmites. This change in the chemical composition signifies a chemical change.

In contrast, a physical change is a change in the form or appearance of a substance but not its chemical composition. For example, melting ice is a physical change because water (H₂O) remains the same molecule, just in a different state.