Weathering and Erosion 4-ESS2-1

Grade 4 - NGSS - CA

The wearing away of rock by other rock or sand particles

Abrasion

The wearing away of rock by other rock or sand particles is called abrasion. Abrasion is when rocks get worn down by rubbing against other rocks or sand.

The breakdown of rock through chemical processes, like acid rain

Chemical weathering

The breakdown of rock through chemical processes, like acid rain, is chemical weathering. Chemical weathering happens when rocks change because of chemical reactions, like when acid rain makes them break down.

The process in which rock is worn away and transported by water, wind or ice

Erosion

The process in which rock is worn away and transported by water, wind, or ice is called erosion. Erosion is when tiny pieces of rock or soil are moved from one place to another by natural forces like wind or water.

When water seeps into a rock, then freezes and expands, cracking the rock

Ice wedge

When water seeps into a rock, then freezes and expands, cracking the rock. Ice wedge. An ice wedge is a crack in the ground that forms when water freezes and expands in cold weather.

The breaking of rocks without any chemical change, like by plant roots

Mechanical weathering

The breaking of rocks without any chemical change, like by plant roots, is called mechanical weathering. Mechanical weathering is when rocks break apart into smaller pieces due to things like plants, water, or wind.

The processes which break down rocks

Weathering

The processes which break down rocks. Weathering. Weathering is when rocks break down into smaller pieces because of wind, water, or temperature changes.