Science Teaching: Earth's Cycles

mineral

naturally occurring, inorganic solid with an orderly, network structure and definite chemical composition

mineral properties (x11)

• color

• odor

• taste

• streak

• luster

• hardness

• cleavage

• crystalline structure

• diaphaneity

• tenacity

• magnetism

streak

the color of the mineral in powder form (by dragging a piece of the mineral across a piece of unglazed porcelain)

luster

the ability of the mineral’s surface to reflect light
metallic, submetallic or nonmetallic

hardness

the mineral’s resistance to scratching (Mohs scale)

softest mineral

talc (1 Mohs)

hardest mineral

diamond (19 Mohs)

Cleavage

the pattern along which the mineral breaks

crystalline structure

the degree to which the mineral is arranged in a crystal lattic structure- more crystalline, the harder the lattice is to see

diaphaneity

the transparency of the mineral or the ability of light to pass through it

tenacity

mineral’s ability to resist separation or breaking when subjected to stress

magnetism

the response of a mineral when exposed to a magnetic material

rock

an accumulation of one or more minerals

Igneous

form when magma lava cools, air pockets or crystals present

granite, obsidian, basalt, pumice, poryphyry

sedimentary

form when sediments (broken rock) like clay build up and become cemented together- they are layered and grainy

sandstone, limestone, shale, chalk, anthracite, siltstone

metamorphic

form when igneous or sedimentary rocks get pulled toward the mantle and is subjected to heat, pressure, or chemical reactions- crystalline, banding or stripes

slate, schist, gneiss, jadeite, marble

Silicates

silicon and oxygen, 30% of all minerals and up to 90% of Earth’s crust are silicates

olivine, pyroxene, amphibole, garnet, topaz, zircon, quartz, mica

oxides

oxygen and metals- ores of chromium, iron, aluminum and magnesium

bauxite, magnetite, hematite

sulfates

sulfur and oxygen (SO4) and other elements- used in construction, some are fluorescent

gypsum

sulfides

sulfur and metals- many have metallic luster and conduct electricity

galena, pyrite

carbonates

carbonate (CO3) and other elements- used as fertilizer and building

calcite (limestone, marble), dolomite

halides

elements such as chlorine and fluorine- water softeners, nutrition

halite (table salt), fluorite

native elements

individual elements-ores are pure

gold, copper, diamond

geologic time scale

formation of Earth to present day

four major eons

• Hadean Eon

• Archean Eon

• Proterozoic Eon

• Phanerozoic Eon

Hadean Eon

4.0-4.5 BYA- earth formed from debris orbiting the sun and the moon was formed

Archean Eon

2.5-4.0 BYA- single celled life forms arose, some continents formed

Proterozoic Eon

540 MYA-3.5BYA- multicellular life arose, later plants and animals

Phanerozoic Eon

541 MYA to present- complex life flourished

accretion

the layers of earth gradually formed by smaller particles colliding and combining to form larger particles, drawing more particles into its gravitational field

Cambrian explosion

explosive increase in biodiversity 5.4 MYA

Cretaceous-Paleogene extinction event

extinction of dinosaurs 66 MYA

interglacial periods

during an ice age- periods when it is warmer and glaciers retreat

glacial periods

in an ice age- when its cooler and glaciers advance

Quaternary Ice Age

2.6 MYA-today
icesheets in Greenland, Antartica, Arctic

Holocene

started 11,700 years ago, a warm interglacial period.

ice ages are caused by…

changes in ocean and atmospheric circulation, varing amounts of CO2, volcanic eruptions, moving tectonic plates that block or allow currents, and regular changes in earth’s orbit

surface water

water that is held on the surface of the Earth (rivers, streams, creeks, lakes, ponds, resrvoirs, glaciers)

groundwater

water held underground in the spaces between rock and soil particles- sits below the water table
can be extracted from aquifers

body of water & 13 types

accumulation of water on the surface of the Earth

• ocean

• sea

• bay

• strait

• gulf

• canal

• lake

• reservoir

• river

• stream

• pond

• geyser

• glacier

ocean

the largest type of water body, composed of saltwater

divided into: Pacific, Indian, Atlantic, Souther, and Arctic Oceans

sea

typically a costal branch of the ocean- sometimes landlocks- saltwater

bay

a coastal body of water connected to a larger water body

strait

a narrow stretch of water between two landmasses; connects two larger bodies of waterg

gulf

an inlet of the sea or ocean bordered on several sides by land

Canal

a man made waterway made to allow boats to pass through or for irrigation purposes

lake

a landlocked basin filled with water; can be freshwater or saltwater

reservoir

a natural or manmade lake used to store water

river

a natural, flowing waterway, composed of freshwater

stream

a natural, flowing waterway; smaller than a river- reshwater

pond

a small body of unmoving water

gayser

a hot spring of water that intermittently jets water and steam into the air; caused by magma heating the groundwater

glacier

a large, slow moving mass of dense ice

abyssal plain

a flat region or plain on the ocean floor

alluvial fan

a fan shaped deposit of sediments at the mouth or opening of a canyon or rivera

atoll

a ring shaped island or coral reef atop submarine volcanoes

bank

an area of higher elevation compared to the seafloor around it, such as a submarine hill

continental shelf

the gently sloping part of the continent that is under the ocean’s surface

continental slope

the region where the continental shelf meets the continental rise; this region is sloped to connect the two

continental rise

the region where the continental slope meets the abyssal plain

tablemount/guyot

an underwater mountain with a flat top

ocean basin

a large submarine area of low elevation

ocean ridge

a feature of increased elevation at the boundary between two tectonic plates; formed at a divergent plate boundary

ocean trench

a long crevasse or fissure in the ocean floor; formed in a subduction zone at a convergent plate boundary

reef

a submarine ridge composed of coral or rocks

seamount

an underwater mountain

shoal

a sandbar or submarine ridge

ocean salinity

average 3.5% or 35 g slat/kg H20

ice caps

sheets of ice that cover the ice poles (very thick and large)

rivers flow

high elevation to low elevation

spring (river)

groundwater flows up to the surface (hot spring)

tributaries

small streams or creeks that feed into the river and increase it water volume

meanders

curvature of a rive. as rivers age they curve in a path of least resistance as they pick up sediments from the outer banks of curves and deposit them downstream on inner banks

oxbow lake

when rivers start curving but finds a new straighter path and abandons meander

flood plain

area that is prone to flooding when the upper part of the river receives a large amount of rain or water from tributaries

outcrop (rock)

rocks formations visible on the Earth’s surface

uplift (rock)

when sedimentary rock get brought back to the surface (outcrop)

sedimentary —> metamorphic

increased temperature and increased pressure. subduction

sedimentary —> igneous

melting

metamorphic —> sedimentary

weathering and deposition

metamorphic —> igneous

melting

igneous —> metamorphic

increased temperature and increased pressure. subduction

igneous —> sedimentary

weathing and deposition

intrusive igneous rock

forms when magma does not break the surface. Earth insulates it and it takes a long time to cool and solidify, allowing large crystals to grow within the rock

ex. Granite

extrusive igneous rock

forms when lava erupts on the surface and cools quickly (no crystals)

ex basalt

water cycle starting on ground

lake body —> evaporation via heat of sun —> X
inside plan —> transpiration to water vapor into air —> X

X. Water vapor rises into the upper atmosphere , cools, condenses from gas to liquid—> droplets stick together forming clouds —> large, heavy droplets fall back to Earth’s surface as precipitation —> Y

Y: precipitation lands in body of water and surface runoff takes to other bodies of water
Y: precipitation lands on ground and percolates into ground to become part of the groundwater supply

what powers the water cycle?

solar energy (heat for evaporation/transpiraton)
gravity (precipitation to fall to ground)

sequence how water moves from Earth's surface into clouds and returns as rain? (phase changes)

evaporation —> condensation —> precipitation

density of water

1 g/cm³ when liquid, less dense when solid

water heat capacity

1 cal/g (highly resistant to change in temperature)

how many hydrogen bonds can each water molecule make?

four other water molecules

Which of the following could form from preexisting rock that completely melts and then solidifies?
a) extrusive igneous rock
b) clastic sedimentary rock
c) chemical sedimentary rock
d) non-foliated metamorphic rock

a) extrusive igneous rock

Which of the following could best be used by a teacher to illustrate the difference between surface water and groundwater?
a) a visit to the school swimming pool or a pool at a nearby park
b) a bowl layered with different kinds of dry breakfast cereal
c) a glass aquarium (no fish), sand, rocks, a small bowl, and water
d) colored water and oil mixed in a jar

c) a glass aquarium (no fish), sand, rocks, a small bowl, and water

Using the table below, which rock is likely to be the most resistant to weathering based on its hardness and grain size?

Rock	Hardness	Grain Size
Marble	3	Fine
Slate	4	Fine
Granite	7	Coarse
Shale	2	Fine

granite

Of the following scenarios, which would be appropriate for use of the Mohs scale?
a) A geologist needs to record the magnitude of an earthquake.
b) A meteorologist needs to categorize a tornado.
c) An astronomer needs to classify a newly-discovered star.
d) A field scientist needs to identify an unknown mineral.

d) A field scientist needs to identify an unknown mineral.

Students find a sample of fine-grained basalt near a dormant volcano. Which of the following processes likely resulted in the formation of the fine grains in this sample?
a) cooling quickly on Earth's surface
b) the breakdown of existing surface rock
c) intense heat and pressure
d) slow cooling beneath Earth's surface

a) cooling quickly on Earth's surface

Sheets of ice currently cover Earth's north and south poles, however, the ice sheets are shrinking. What is the most likely reason the ice caps are currently shrinking?
a) The tilt of Earth's axis is changing.
b) Tectonic plates are moving toward the poles.
c) Increased CO₂ in the atmosphere is rising temperatures.
d) The northern hemisphere is closer to the sun during the winter.

c) Increased CO₂ in the atmosphere is rising temperatures.

Which of the following statements most likely describes a metamorphic rock?
a) a light, very porous rock with visible holes, grains that are too small to see, and no fossils
b) rocks formed by cementation of other particles are sedimentary rocks
c) a rock that is soft and grainy
d) a rock with wavy bands of minerals that is very hard and has visible crystals

d) a rock with wavy bands of minerals that is very hard and has visible crystals

flat-topped underwater mountain

tablemount

tablemount vs seamount

tablemount- flat topped underwater volcanic mountain
seamount- underwater mountain- not flat topped