1. What role does WEATHERING play in the rock cycle?
The SHOWDOWN!
Weather vs. Rock! Who wins?
The Rock Cycle...
ESRT p 6
What role does WEATHERING play in the rock cycle?
It changes ANY TYPE of rock into sediments!

2. and the ________________
Weathering...
The breakdown of ROCK into SEDIMENTS
Lithosphere
Weathering happens when the ____________ is exposed to the _________________
and the ________________
Atmosphere
Hydrosphere
Weathering: Rocks are exposed to weather!

3. Weathering... Two Types Chemical Weathering EXAMPLES Oxidation
Rocks break down when chemical reactions change their composition
EXAMPLES
Oxidation
Hydrolysis
Minerals react with oxygen in the air
Minerals react
with water

4. Chemical Weathering... Cleopatra’s Needle
The symbols dissolved in the humid weather of NYC!

5. Weathering... Physical Weathering… aka mechanical weathering EXAMPLES
Rocks break down into smaller pieces BUT DO NOT change composition…they just get smaller!
EXAMPLES
Exfoliation
Abrasion
Rock breaks off in layers from pressure release
Rocks wear away by wind, streams
Wedging
Ice or roots expand cracks in rocks

6. Physical Weathering... Exfoliation
Rock breaks off in layers from pressure release
Mt Haystack, NY

7. Physical Weathering...
Wilmington, NY

8. Physical Weathering... Root Wedging
Root grows in crack and splits the rock WIDE OPEN!
Blue Mountain
Lake, NY

9. Weathering Summary What is weathering?
What is the main difference between chemical and physical weathering?
Both types of chemical weathering do what?
All types of physical weathering do what?
Which type of weathering do you think we mostly have here in Pittsford? Explain…

10. Weathering Factors... Climate...
MOST IMPORTANT FACTOR
Weathering rate depends on the WEATHER!
WHY?
Weathering happens faster in ____________ climates
Weathering happens slower in _________ climates
WARM and HUMID
COOL and DRY

11. OTHER Weathering Factors...
Rock type
Igneous vs. Sedimentary
Which type weathers faster?
Usually sedimentary
Made of sediments cemented together that can be separated!
WHY?
Igneous rocks have inter-grown crystals

12. OTHER Weathering Factors...
Particle Size OR
Which size weathers faster?
WHY?
Smaller particles have greater exposed surface area

13. Weathering... SUMMARY 1. Two types of WEATHERING...
2. How does CLIMATE affect weathering?...
3. How is rock type a weathering factor...
4. Which rock will probably weather faster in the same climate, shale or sandstone? Why?
5. Choose a rock and explain where and why it would weather very slowly...

14. Weathering in our area…
What kind of WEATHERING do WE have?
Mostly Physical...
WHY?
POTHOLE
Lots of precipitation/humid
Frost wedging causes potholes!
Water in the pavement freezes and cracks the road. Cars break the cracks!

15. Weathering in New York State…
1895, Frederick Douglass
Rochester, NY
115 years old and still looks good!
How is that possible?
Probably made from tough, weather-resistant granite!

16. Weathering in New York State…
1895, Harold McWillie
Rochester, NY
Same age and Douglass’
REALLY WEATHERED!
What made the difference?
Made of limestone!

17. Weathering in other areas…
Great Sphinx, Egypt
3000 B.C.E.
Made of limestone!
What made the difference?
Dry climate, less pollution!

18. Weathering… Cleopatra’s Needle, Egypt (1500 BCE) Still in great shape!
Dry climate, not much pollution!

19. Weathering… Cleopatra’s Needle, NYC (1500 BCE)
What made the difference?
Humid climate, pollution,
acid rain dissolved the linestone!

20. Weathering... Weathering Video! SUMMARY
How can a 150 year old tombstone still have clear lettering?
How can a newer 50 year old tombstone be almost unreadable?
How is it possible for 5000 year old statues in Egypt to still look fresh?
How might global warming and acid rain affect weathering rates in New York State?
Weathering Video!