How Do Weathering and Erosion Unit 3 Lesson 1 How Do Weathering and Erosion Shape Earth’s Surface?

Today’s Learning Goal I will be able to list the basic differences between physical weathering (breaking down by wind, water, ice, temperature change, and plants) and erosion (movement of rock by gravity, wind, water, and ice).

What Can Break a Boulder? The process of rock breaking apart is called weathering. Many things cause weathering. Gravity, flowing water, blowing sand, living things, ice, and chemicals can cause weathering.

How Strong Are Plant Roots? Plant roots are so strong they will actually bust rock apart. As the plant grows, the roots bust the rock even more.

Rocks on the Move Weathering is the beginning of a series of changes that often happens to rocks on Earth’s surface. The process of moving weathered rock from one place to another is called erosion.

How Are Erosion and Weathering Different? Weathering breaks down rocks Erosion moves rocks to another place. Weathering happens over time. Erosion can happen instantly.

Rocks on the Move Moving water is one of the most common causes of erosion. Moving water is what makes rocks smooth. Fast-moving water and gravity can cause rocks to move downhill. Water erosion is how we get small rocks.

Rocks on the Move As the water in a river slows down, bits of weathered rock are dropped. These bits of rock are called sediment. The dropping of weathered rock by wind or moving water is known as deposition.

Rocks on the Move Rivers carry rocks and other sediment from upstream to the mouth of the river. As rivers carrying sand and silt reach the ocean and slow down, sediment is dropped. Over time, the sediment forms a delta.

Rocks on the Move What size of sediment drops out first? What size drops out last?

Wind Wind can carry soil and other sediment near and very far away. Winds may deposit a lot of sand in one area. Over time, the sand builds up and forms dunes. Sand dunes often are found near sandy beaches.

Ice Huge sheets of ice are called glaciers. They are found in very cold places. As glaciers flow, they move boulders, rocks, and sediment. When the glacier melts, the sediment forms many landforms, including moraines.

Gravity Gravity can cause rocks and sediment to slide down mountains and cliffs. Sometimes it falls all at once in an event called a landslide. Landslides often occur in mountain ranges. The steeper the mountain slope, the more likely the rocks are to fall.

Flowing water and ocean waves can break rocks apart. The constant weathering of rocks and shells is how beach sand is formed. The constant bumping and scraping against each other is how rocks grind down to sand. Ocean waves cut cliffs, form caves and sea arches, and carry away and redeposit sediment.

Water The movement of water in rivers cause weathering by creating canyons. The flowing motion and constant erosion of the soil is how riverbeds and canyons are formed.

REVIEW - Today’s Learning Goal I will be able to list the basic differences between physical weathering (breaking down by wind, water, ice, temperature change, and plants) and erosion (movement of rock by gravity, wind, water, and ice).