1. Weathering & Erosion

2. Engage
The Power of Ice
Have the students hypothesis what will happen if you freeze water in a cup with a lid one day and then freeze over night

3. Explore Journal- What do you know about weathering and erosion
Brain Pop- Weathering, Erosion
Assign notes and vocab

4. Explain- Weathering and Erosion
Weathering - processes at or near Earth’s surface that cause rocks and minerals to break down
Erosion - process of removing Earth materials from their original sites through weathering and transport

5. Weathering and Erosion
Weathering is the break down of rocks that have been exposed to the atmosphere
Once the rocks are broken down, the pieces are transported from one place to another. This process is called erosion
Erosion is caused by wind, moving water (streams, waves, ocean currents), ice (glaciers), and by gravity.
*Most erosion that takes place on Earth is caused by moving water

6. Types of Weathering
  Mechanical weathering – rocks are broken down into smaller pieces without changing their composition (doesn’t change what they’re made of)
Chemical weathering - rocks break down as their minerals change in composition (they become different substances)

7. Types of Mechanical Weathering
Ice wedging/frost action
water enters small cracks in the rock
When it freezes, it expands and forces the crack to open more
The process repeats over again until the rock breaks apart

9. Eventually, the rock splits from repeated frost action!

10. Types of Mechanical Weathering
Wetting and drying
breaks up rocks that are made from clay
When they are wet they expand, and they shrink as they dry
As this repeats over and over, the clay becomes weak and cracks (think of all the projects you have made out of clay…they all crack and fall apart)!

12. Types of Mechanical Weathering
Exfoliation
soil and rock is removed (glaciers or uplifting), exposing rock found deep underground
This releases the pressure causing the surface of the rock to expand and eventually crack

14. Types of Mechanical Weathering
Plant Roots
The deep roots of trees often break apart rocks
Lichen & Moss
These low to the ground plants can grow on rocks and eventually break them apart

16. Types of Chemical Weathering
Hydrolysis
water (hydro) reacts with minerals such as feldspar and form clay

18. Types of Chemical Weathering
Oxidation
oxygen reacts with some minerals, especially those containing iron (magnetite) to form rust (called iron oxide)
This occurs faster with water!

19. Oxidative weathering of mineral deposits (new deposits are white/yellow, weathered deposits are reddish-brown)

20. Types of Chemical Weathering
Carbonic acid
carbon dioxide (CO²) dissolves in water to form this acid
can cause minerals to dissolve, especially those containing calcite

21. “Gnarled Rock” – a formation of limestone chemically weathered by acid rain

24. Factors which affect rates of weathering:
Rock’s resistance to weathering (HARDNESS)
Amount of surface area
Climate:
Chemical weathering occurs faster in warm, wet climates
Mechanical weathering occurs faster in cold or dry climates

25. Surface Area Greater surface area increases the rate of weathering
Surface area is the amount of rock surfaces exposed to the atmosphere
Weathering creates more surface area

27. Dry Climate = Mechanical Weathering!
Devil’s Marbles, Australia – Mechanical weathering from wind and sand!

28. Warm Climate = Chemical Weathering
Parthenon – Athens, Greece

29. What is Erosion? Agents of erosion:
Erosion – moving of rock material from one place to a new location
Three processes must take place:
detachment of particles
lifting them
transporting them
Agents of erosion:
flowing water
moving ice
waves
gravity
Wind

30. Wind Erosion
Wind – wears away rocks and is responsible for the creation of deserts such as the Sahara and the Gobi
- Most effective in moving loose material
Main effects:
Wind lifts small particles and moves them away.
Suspended particles may cause erosion on solid objects by abrasion (rubbing).
Occurs in areas where there is not enough rainfall to support vegetation

31. What Is Water Erosion? Water – most influential force in erosion
Moves materials
Transports large objects with fast moving streams
Wears away rocks:
rivers
lakes
oceans

32. What is Deposition?
Deposition – laying down of sediment that has been transported by a medium such as wind, water, or ice
Process of erosion stops:
when the moving particles fall out of the transporting medium and settle on a surface
Speed of the medium slows or the resistance of the particles increases, the balance changes and causes deposition
Speed can be reduced by large rocks, hills, vegetation, etc.

33. Deposition - Wind
Wind speed can be related to variations in heating and cooling.
Transportation of particles in wind:
Fine particles in suspension hundreds of km from its original source in the desert
Heavier material may be blown along the ground.
Material is deposited when the wind changes direction or loses its strength.

34. Deposition - Water
Running water enters a large, fairly still body of water and its speed decreases
SPEED
As the speed of the water decreases, the water's ability to carry sediment also decreases.
Deposited in streams, rivers, and oceans:
Running water deposits sediments where the slowing water can no longer move them.
Largest particles are deposited near the shore.
Increasingly smaller particles settle out farther from the shore where the water is calmer.

35. Deposition - Ice
Glacial flows of ice – become slower when the ice begins melting
– Deposits left by glaciers:
Outwashes are deposits similar to those left by rivers.
Large chunks of broken rock deposited at the base and sides of the glacier as it melts and recedes are called Moraines.
When the glacial ice melts, smaller material is carried by the rivers.

36. What’s the Difference?
WEATHERING – Think of weather wearing rock down.
EROSION – Think of a road and traveling.
DEPOSITION – Think of depositing money into a bank.

37. Physical Weathering is
A- minerals reacting chemically with water B- Rock breaking apart due to ice C- rock and dirt being moved away by water D- Rock and dirt being relocated to another place E- none of the above

38. Erosion is?
A- minerals reacting chemically with water B- Rock breaking apart due to ice C- rock and dirt being moved away by water D- Rock and dirt being relocated to another place E- none of the above

39. Chemical Weathering is?
A- minerals reacting chemically with water B- Rock breaking apart due to ice C- rock and dirt being moved away by water D- Rock and dirt being relocated to another place E- none of the above

40. Deposition ?
A- minerals reacting chemically with water B- Rock breaking apart due to ice C- rock and dirt being moved away by water D- Rock and dirt being relocated to another place E- none of the above

41. Elaborate Sorting Activity- Weathering, Erosion, or Deposition
3 part skittle lab
Read science- Mount Everest

42. Evaluate
Weathering and Erosion Worksheet