Here's how:

Physical Weathering:

* Freezing and thawing: Water expands when it freezes, putting pressure on rocks. Repeated freezing and thawing can cause rocks to crack and break apart.

* Abrasion: Water carrying sediment (like sand and gravel) can wear away rock surfaces through abrasion. Think of how a river carves a canyon.

Chemical Weathering:

* Dissolution: Water can dissolve certain minerals in rocks, like limestone and halite (rock salt). This process weakens the rock and can cause it to crumble.

* Hydrolysis: Water molecules can react with minerals in rocks, changing their chemical composition and making them weaker.

* Oxidation: Water can accelerate the oxidation of minerals like iron, causing rusting and weakening the rock.

In summary: Water is a powerful agent of both physical and chemical weathering. It can break down rocks by mechanical forces (physical) and by changing their chemical makeup (chemical).