* Sandstone is composed of mineral grains (primarily quartz) that are cemented together.
* Erosion breaks down the sandstone into smaller pieces, such as sand grains.
* The chemical makeup of the quartz grains remains unchanged. They are simply separated from each other.
Contrast this with a chemical change:
* A chemical change involves breaking and forming new chemical bonds, resulting in the formation of entirely new substances.
* For example, if sandstone were to react with acid, the acid would dissolve some of the minerals in the sandstone, creating new substances.
In summary: Erosion of sandstone is a physical change because it only involves breaking down the rock into smaller pieces without changing the chemical composition of the minerals within it.
