1. For the food chain shown, which of the following changes would have the most severe consequences?
A a drastic decrease in rainfall, causing drought
B the poaching of predatory hawks by game hunters
C the introduction of a second predator that eats field mice
D a parasitic infestation that reduces the cricket population C

2. Rocks and Volcanoes

3. Rocks and the Rock Cycle3

4. Earth’s Rocks and the Rock Cycle
Rocks can be found everywhere on Earth. Rocks are a naturally occurring solid mixture of minerals and (sometimes) organic materials.
Rocks are classified by
mineral and chemical composition
texture of the particles
and also by the processes that formed them.

5. Igneous
sedimentary
metamorphic

6. Igneous Rocks Formed from lava or magma (Both are molten rock)
Magma= underground
Lava = above ground
Types of igneous rock
Intrusive: form when magma cools
Large crystals (coarse-grained)
Extrusive (Volcanic): form when lava cools
Small crystals (fine-grained)
Think: Why are the crystal sizes different?

7. Igneous Rock Where does Igneous Rock come from?
crystallize from cooling magma

8. Intrusive Igneous Rock
Rocks form from magma cooling beneath Earths surface
Coarse grained
Large crystals form and grow
Takes a long time to cool and harden
e.g. granite

10. Extrusive Igneous rocks
Forms from magma that is brought to Earths surface (lava)
Lava cools more rapidly so large crystals do not have time to form
Fine grained
e.g. Obsidian, pumice

11. Obsidian Pumice

12. Color of Igneous Rock Rocks high in silica are lighter in color
Rocks low in silica are darker in color
Silica-
A chemical compound that is the main constituent of most of the Earth's rocks.
the main chemical compound in sand.
Silica is used to make glass, concrete, and other materials.

15. Check for understanding
What is molten rock below the surface?
What is molten rock above the surface?
What type of rock forms from magma?
What type of rock forms from lava?
What can you assume about the composition about a light colored sample of igneous rock?

16. Check for understanding
Fine grained igneous rock has _____ crystals.
Small crystals form in ______ igneous rock.
Coarse grained igneous rock has ___ crystals.
Large crystals form in ______ igneous rock. 16

18. Which of the following atoms has the largest atomic radius?
A barium (Ba) B chlorine (Cl)
C iodine (I) D magnesium (Mg)
Which of the following atoms has six valence electrons?
A magnesium (Mg) B silicon (Si)
C sulfur (S) D argon (Ar)
3/3/11

19. Weathering and erosion
Mechanical: physical breaking of rock by abiotic means (e.g. ice expanding in cracks)
Chemical: rock dissolved by acids
Biological: plants breaking rock with their roots
Erosion: movement of dissolved or fragmented rock
Deposition: rock material comes out of solution or suspension

20. Sedimentary rocks (rock on!)
formed from compressed or cemented layers of sediment
Types
Clastic: formed from pieces of other rocks that are glued together. (e.g. Sandstone)
Chemical: formed by precipitation of elements dissolved in water (e.g. rock salt, limestone)
Organic: formed from remains of living things (e.g. coal)

22. The Deadly Crystal Cave

24. Check for understanding
How is sedimentary rock formed?
What type of sedimentary rock is formed from the remains of living things?
How is rock broken down?
What type of sedimentary rock is formed from small rocks that are stuck together?
What type of sedimentary rock is formed when chemicals precipitate out of solution?

25. Metamorphic Rock
A rock that forms from other rocks as a result of intense heat, pressure, or chemical processes.
There are two basic types of metamorphic rocks:
1) foliated metamorphic rocks such as gneiss and slate which have a layered or banded appearance
2) non-foliated metamorphic rocks such as marble which do not have a layered or banded appearance.

26. Metamorphic Rock
Some examples:
Limestone  marble 
shale slate 

28. The Rock Cycle!

30. The rock cycle

32. Volcanoes

34. Violent eruption

36. Volcanoes What is lava? How does molten rock get to the surface?
Volcano: an opening in a planet's surface or crust, which allows hot magma, volcanic ash and gases to escape from below the surface.
Extrusive igneous rock
is also known as “volcanic”

37. Viscosity is a measure of the resistance of a fluid
viscosity is "thickness" or "internal friction".
water is "thin", having a lower viscosity
honey is "thick", having a higher viscosity.
The less viscous the fluid is, the greater its ease of movement

39. Volcanoes
there are two kinds of volcanoes: ones with violent eruptions producing steep slopes and ones with voluminous lava flows producing gentle slopes.

40. Volcanic Eruption on Io

41. Volcanoes
Shield volcanoes, so named for their broad, shield-like profiles, are formed by the eruption of low-viscosity lava that can flow a great distance from a vent, but not generally explode catastrophically.
low-viscosity magma is typically low in silica (<52%), but high in Magnesium and Iron
(e.g. The Hawaiian islands)
Mild eruptions

42. Shield Volcano, Iceland

43. Kilauea HI

44. The size of Olympus Mons is so great (roughly the size of Missouri) that a person standing on the surface of Mars would be unable to view the profile of the volcano. The only way to view the mountain properly is from orbit.

45. Volcanoes
cinder cones are the result from eruptions that erupt mostly small pieces of pyroclast that build up around the vent. These can be relatively short-lived eruptions that produce a cone-shaped hill perhaps 30 to 400 meters high.
Silica content above 52%
High viscosity magma
Violent eruptions

46. Cinder Cone Volcano

47. Volcanoes
composite volcanoes are tall conical mountains composed of lava flows, cinders and ash in alternate layers
Silica content above 52%
Violent eruptions

48. Mt Fuji, Japan (composite volcano)

49. Mt St Helens, prior to 1980

50. Mt St Helens, after 1980

51. Volcanoes

52. The Ring of Fire
An area where large numbers of earthquakes and violent volcanic eruptions occur in the basin of the Pacific Ocean.
It is associated with a nearly continuous series of tectonic plate boundaries and movements.
It has 452 volcanoes, over 75% of the world's active and dormant volcanoes.
Violent volcanic eruptions

53. The Ring of Fire

54. Our local portion of the Ring of Fire

55. Check for understanding
What effect does high silica content have on rock color?
High silica, light color
What effect does high silica content have on magma viscosity?
High silica, high viscosity
Volcanoes with high viscosity magma have ______ eruptions
Violent
Volcanoes with high viscosity magma have ______
Mild eruptions

56. Check for understanding