Chemical Weathering
Chemical weathering is the breakdown of rock when rain or other liquids react with the stone and dissolve it.
Drop a sugar cube into a glass of water. The water slowly dissolves the cube from the outside in. The cube shrinks and crumbles as the water breaks apart its edges. Rain does the same thing to rock — it seeps into cracks and dissolves the minerals that hold the stone together.
Explaining chemical weathering by grade level
Rain is not just water. It has tiny bits of acid mixed in. When acid rain falls on a marble step, it eats away at the stone bit by bit. Over time, the smooth step gets rough and worn down.
Projects that explore chemical weathering
Acid reacts with marble and dissolves it over time — the same process that slowly eats away at stone buildings and sculptures exposed to acid rain. A calcium oxalate coating may interrupt this reaction by forming a protective layer on the stone's surface. In one test, an uncoated marble tile lost the most weight after five days in vinegar, while a calcium oxalate-coated tile held up much better against the acid.
When acidic liquids react with rock, they dissolve it — and vinegar mimics that same effect on stone and brick. Soaking four building materials in vinegar for four days reveals just how unevenly this breakdown happens. Limestone loses almost 90% of its weight by day four, while granite stays nearly the same.