One type of physical weathering not covered in the videos is abrasion. A scratch on your skin or eye is called an abrasion and an “abrasive” person is someone that grates on your nerves. So, this form of weathering is just like it sounds. When sand or silt is picked up by water or wind and bumps into other rocks, it can round off the edges, making things smooth.
River rocks are rounded because they roll around in rivers, bumping into one another and chipping off their rough edges. Sand carried by river water acts like sandpaper, smoothing the surface of the rocks. For example, see this photograph of rounded pebbles.
Abrasion also happens as a result of wind carrying sand. Visit Devil's Garden in Grand Staircase – Escalante National Monument in Utah. The towers of rock are called hoodoos. How are Devil's garden hoodoos an example of differential weathering? Provide evidence from your observations of the 360° photo.
