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

2. 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).

3. 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.

4. 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.

5. 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.

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

7. 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.

8. 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.

9. 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.

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

11. 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.

12. 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.

13. 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.

14. 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.

15. 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.

16. 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).