they hide under rocks so they can hide from predictor's like humans.
why are most of rocks extremely smooth
By weathering. The water currents weather the rocks leaving them smooth.
Very smooth rocks are called "polished rocks" or "river rocks" due to the smooth texture achieved from erosion in water bodies like rivers and oceans.
typically, Pumice rocks are used to scrape the rough areas of feet so that they are smooth
As the cobbles and pebbles are carried downstream by the stream, they constantly collide with each other and with the streambed, causing abrasion. This abrasion gradually wears away the rough edges and corners of the rocks, resulting in their smooth and rounded appearance. The longer the rocks are transported by the stream, the more worn down they become.
physical change
Rocks become smooth in water due to a process called abrasion, where they are constantly rubbed against each other and other materials, such as sand and sediment, while being transported by flowing water. This continuous friction gradually wears down sharp edges and rough surfaces, resulting in a smoother texture over time. Additionally, the tumbling motion of rocks in streams and rivers further contributes to their polished appearance.
Wind and ice can cause physical weathering in rocks by breaking them apart through processes like freeze-thaw cycles and abrasion. Over time, this can lead to the formation of cracks, fractures, and eventually the breakdown of rocks into smaller pieces.
mica
some from weathering
Smooth rocks on a beach are often the result of continuous erosion caused by water and sand rubbing against the rocks over time. The motion of waves can wear down the rough edges of the rocks, making them smooth.