Water gets into cracks and joints in bedrock. When the water freezes it expands and the cracks are opened a little wider. Over time pieces of rock can split off a rock face and big boulders are broken into smaller rocks and gravel.

When water in a river or stream moves quickly, it can lift up rocks from the bottom of that body of water. When the rocks drop back down they bump into other rocks, and tiny pieces of the rocks can break apart.

Roots of plants growing into cracks may put pressure on the surrounding rock, eventually breaking rocks apart as the roots grow.

Each area has varying temperature and pressure conditions. This fluctuation leads to the constant expansion and contraction in rocks. This reduces the strength of the rocks, which further breaks them down.

Lichens cling to the surface of the rocks. They can produce organic chemicals which cause break down of the rocks.

Wind carries sand particles while traversing from one place to another. These particles are abrasive in nature. They hit the rocks, thus imparting shape to them.

The Colorado River flowed over rock for prolonged periods, eventually forming the Grand Canyon.

Water comes in contact with granite and the feldspar crystals inside the granite react chemically, forming clay minerals. The clay weakens the rock, making it more likely to break.

When oxygen reacts with iron, iron oxide (rust) is formed. Rust changes the color of the rocks, plus iron oxide is much more fragile than iron, so the region becomes more susceptible to breakage.

Carbonic acid, a weak acid, is produced when carbon dioxide reacts with water. Carbonation is an important process in the formation of many caves and sinkholes. Calcite in limestone dissolves under acidic conditions, leaving open spaces.

A storm brings heavy rain to an area. On the hillside, the soil is washed away with the rain.

Waves carry sand and, when they crash on the shore, they leave some of that sand on the shore.

Soil and sediments being carried by a river accumulate over time. Eventually, a delta is formed where the river flows into a slower moving body of water.

Wind carries sand from a desert to new locations.

Glaciers drag across landforms and scrape off the top layer of rock.

Fast moving rivers pick up mud and sediments, carrying them through the river.

A hurricane brings heavy rains that flooded a whole city. Soil was picked up and moved across the city during the flooding.

Gravity causes sheets of rock from the side of a mountain that have been broken down over time to fall down the side of the mountain.

Waves hitting the side of a cliff take small parts of the rocks on that cliff and carry them into the ocean.

Sediments that have been broken down from a cliff that meets the ocean are carried into the water and they settle at the bottom of the ocean. Layers of sand build up over time.

Sand is carried long distances and begins to accumulate in desert regions. Over long periods, whole dunes of sand are formed in the desert from the sand that was carried by the wind.

Rock and coral reefs are broken down in the ocean. These pieces are carried by waves and eventually get dropped onto the shore. The formation of a beach from these sediments is called...

Rock pieces carried by glaciers get left behind when parts of the glacier begin to melt.