Transcript Chapter 10-Core

Module 3 – Earth’s Crust
Chapter 10 – Minerals, Rocks,
and Soil
Canada
• Canada is known world-wide for its large fields
and impressive landscapes.
• For example, Newfoundland is known as « The
Rock ».
• Also, tourists come see the Rocher Percé in
Gaspésie. Others come see the Thousand
Islands, the Rockies, the Prairies, the mountains
in New Brunswick and British Colombia, and the
long sandy beaches in Prince Edward Island
and Nova Scotia.
Newfoundland a.k.a. “The Rock”
The Rockies
Mountains in New Brunswick and
British Colombia
• NB
BC
…Thousand Islands
Beaches in PEI and NS
The Prairies
Reflection Questions
• Why are some gemstones valuable while
others are worthless?
• Why do plants grow in some places and
not in others?
• What is the most valuable gemstone?
Chapter 10 – Key Ideas
• In this chapter, you will discover:
– How minerals, rocks, and soils form and
continue to change in a cycle
– How soil types and crops vary across
Canada
– How human activity affects our
environment positively and negatively
10.1 – Minerals
• Mineral: is inorganic (lifeless) solid matter
that is natural, and composed of one or
more elements.
• Rock: a rock is made up of one or more
pure, naturally occurring, non-living solid
substances (minerals). A part of the
Earth’s Crust is made out of rock.
Minerals
• Most minerals are quite rare. Only a few
(quartz and mica) are common and are found
throughout the Earth’s crust.
quartz
mica
Minerals
• A mineral can be an element (a pure
substance) or a compound (two or more
substances).
• No other mineral has the same set of
properties or proportion of elements.
Mineral Formation
Minerals can be formed in 3 ways:
1. Lava and magma cool off and form crystals.
2. A solution evaporates and there are dissolved
crystals left in the solution.
3. Existent minerals are sometimes exposed to high
temperatures and to strong pressures or are
dissolved in a solution; they finish off as new
minerals.
Jewelry
• Most jewels are not made up or gold,
silver, or platinum. In a natural state these
substances are soft and very flexible.
• So they will keep their shape and appear
smooth, they must be hardened. They
often mix gold, silver and platinum to other
metals.
How Hard are Minerals?
• Which mineral is the hardest?
– The diamond is the substance that is the
hardest of all minerals!
• A German scientist called Friedrich Mohs
created a scale of ten minerals with a
« hardness » value of 1 to 10.
The Mohs Hardness Scale
• The Mohs Hardness Scale is a useful tool
for mineral identification.
• Given that there are over 3000 minerals,
other properties are also needed to
identify them.
How do we use the scale?
• Suppose that you have an unknown mineral that
looks like another mineral such as talc. If you
scratch it with your fingernail, and it scratches
easily, then it could be talc (it is number 1
according to Mohs Scale). If it does not scratch
easily, then it is not talc.
• Minerals that are low on Mohs’s scale are softer
then those at the bottom of the scale (7 and up).
What to do now…
1. In the team shared folder, there is a document
“Major Crystal Systems”. Save this document in
your folders.
2. Fill out the tables and answer the questions. The
website you are to use for the first table is on that
document.
3. For the second part (on birthstones) you may use
the website of your choice.
Tuesday, May 1st 2007
1. Finish the document begun yesterday
from the Team Shared Folder “Major
Crystal Systems”.
2. If you finish before the others, work on
your “Famous Scientists” project.
3. We will correct the worksheet today.
Other Clues to Mineral Identification
LUSTRE: (shiny)
COLOUR:
Most dull minerals are nonmetals. The “shininess”, or
lustre, of a mineral depends on
how light is reflected from its
surface.
Not all minerals are the same
colour all the time. Colour is one
of the most attractive properties
of minerals.
STREAK:
CLEAVAGE and
FRACTURE:
A streak is the colour of the
powdered form of the mineral.
Gold leaves a gold streak.
Minerals that are too hard will
not leave a streak (7 on Mohs
Scale).
The way a mineral breaks apart.
Cleavage = when it breaks
along smooth, flat surfaces.
Fracture = breaks with rough or
jagged edges.
The Six Major Crystal Systems
•
All of the minerals in Earth’s crust can be
grouped according to the 6 different crystal
shapes.
1.
2.
3.
4.
5.
6.
Cubic / isometric
tetragonal
hexagonal
orthorhombic
monoclinic
triclinic
Rock Jokes
What does a rock want to be when it grows up?
– A Rock Star
What do you do to a baby rock?
– Rock it
Where do rocks sleep?
– Bedrock
Section 10.2 –The cycle of rocks
There are 3 major rock families (categories):
1) Igneous rocks
2) Sedimentary rocks
3) Metamorphic rocks
• Each can usually be identified by its
appearance.
Igneous Rocks
• Igneous rocks: form when hot magma
and when hot lava cool and solidify.
• Magma: is melted rock found below
Earth’s crust, where temperatures and
pressures are high.
• Any rock that is heated at great depths
can melt into magma.
Intrusive vs Extrusive
• Intrusive rocks: are made when magma
cools down and hardens below the Earth’s
surface.
• Extrusive rocks: are formed when lava
cools down on the Earth’s surface.
• (Lava is magma that comes through the
cracks of the Earth in the form of a volcanic
eruption).
Sedimentary Rock
• Sedimentary rocks: are formed from
sediments – loose materials, such as bits
of rock, minerals, and plant and animal
remains. These sediments become
closely packed and cemented together.
• This type of rocks make up about 75% of
the rocks we see on the Earth’s surface.
Granite
• Granite is a rock that is made up of an
assortment of minerals.
• Its is often polished and used in buildings and at
the base of statues.
• Granite contains these minerals:
–
–
–
–
feldspar (sparkling grains)
quartz (a glassy crystal)
mica (greenish-grey flakes)
hornblende (dark flecks).
Metamorphic Rock
• This type of rock has changed its form
from what it was originally. It is formed
below the Earth's surface by extreme
pressure and heat.
• The “parent rock” will become another
type of rock depending on how much
pressure and heat is used to change it.
Minerals and Metals at Home!
Which minerals are hidden in these outdoor objects:
a) skateboard: aluminum, calcite, iron, mica, nickel,
petroleum products, clays, silica and talc.
g) window: nepheline syenite and silica.
f) sidewalk (concrete): gypsum, iron, limestone, clays and
silica.
h) roof/shingles: petroleum products.
k) bricks: graphite, clays and silica.
Rock Jokes
• What is a rock's favorite kind of music?
– Rock n’ Roll
• What is a rock's favorite transportation?
– A rocket
• What is a rock's favorite cereal?
– Cocoa Pebbles
Minerals and Metals at Home!
Which minerals are hidden in these kitchen objects:
a) telephone: copper, gold and petroleum products.
c) fridge: aluminum, copper, iron, nickel, petroleum
products and zinc.
e) toaster: copper, iron, nickel, mica, chromium and
petroleum products.
i) clock: includes iron, nepheline syenite, nickel,
petroleum products and silica.
n) dishes/plates: clays.
Minerals and Metals at Home!
Which minerals are hidden in these office objects:
a) stereo: gold, iron, nickel and petroleum products.
b) cd: aluminum and petroleum products.
c) chair: aluminum and petroleum products.
d) desk: copper, iron, nickel and zinc.
f) camera: aluminum, iron, gold, nepheline syenite,
nickel, petroleum products, silica and silver.
g) books: limestone and clays.
Minerals and Metals at Home!
Which minerals are hidden in these bathroom objects:
a) bathtub: clays, iron and nickel
e) cleaning product: silica
g) toothpaste: fluorite, barite and calcite
i) jewelry: copper, gold, iron, nickel or silver.
k) drinking glass: nepheline syenite and silica
n) faucet: iron and nickel
Minerals In Rocks
• The building blocks of rocks are naturally occurring materials,
called minerals. Rocks contain naturally occurring, non-living
minerals. Most minerals are rare and can be elements (pure
substances) or compounds (combinations of pure
substances).
• Minerals are not only found in rocks, but they are also found in
your body.
– Iron and pyrite help the blood carry oxygen
– Kidneys produce crystals, called kidney stones
– Calcium and dolomite help regulate water in body cells
- Diamonds are used in surgery, razor blades, computers,
dentistry, oil drilling and a glasscutter's wheel has diamonds
embedded in it.
The Rock Cycle
• So far, we have seen that rocks are
constantly changing.
• Rocks continue to change in an ongoing
process called the rock cycle.
Rock Sayings
•
•
•
•
•
Your head is as hard as a rock.
I am between a rock and a hard place.
He is just a chip off the old rock.
Your head must be full of rocks.
She has a heart of stone (or heart of
gold).
Source: http://library.thinkquest.org/J002289/sayings.html
Test Review for Chapter 10
1. The 3 major rock families & how they are formed
2. The difference between a rock and a mineral
3. Mohs’ Hardness Scale (scale of 1 to 10 and which
mineral is the hardest)
4. Intrusive rocks vs. Extrusive rocks
5. Magma and Lava
Review questions
Sciencepower 7:
1. p. 310 # 7, 11, 19
2. p. 288 # 1, 2
3. p. 299 # 1
Review - Answers
p. 310
#7. A mineral that is cleaved has smooth, flat
surfaces. A mineral that is fractured has rough or
jagged edges.
#11. Magma is melted rock formed under the
Earth’s crust.
Lava is magma that comes through the cracks
of the Earth in the form of a volcanic eruption.
#19. Diagram
Review - Answers
p. 288
# 1. Rock: a rock is made up of one or more pure,
naturally occurring, non-living solid substances
(minerals). A part of the Earth’s Crust is made out
of rock.
Mineral: is inorganic (lifeless) solid matter that is
natural, and composed of one or more elements.
Element: a pure substance
Review - Answers
P. 288
#2. LUSTRE (shiny), COLOUR, STREAK,
CLEAVAGE and FRACTURE.
p. 299
# 1. One or more minerals
10.3 – Soil
• Sediment is an in-between stage in the rock
cycle.
• The slow process of rock formation takes
thousands of years to occur.
• Rock sediment is commonly called dirt but what
most people call dirt is actually soil.
• Soil: is a mixture of weathered rock, organic
matter, mineral fragments, water, and air.
Formation of Soil
– Earth is covered by a layer of rock and sediment.
Sediment and mineral fragments do not become
soil until plants and animals have lived in them
and added organic matter (leaves, twigs, and
dead worms and insects).
– The organic matter creates spaces that can be
filled with air or water. All of these combine to
form soil, a material that can support plants.
Soil Profiles
• Soils can take thousands of years to form.
• The can range in thickness from 60 m in
some areas to just a few centimeters in
others.
• The layers of soil make up a soil profile.
Soil Texture
• Texture: how soil feels when it is rubbed
between your fingers. The particle size
affects how gritty a soil feels.
• Water-holding capacity: the soil’s ability
to hold water. Soil with low water-holding
capacity tends to be dry most of the time.
Chapter 11:
Earthquakes,
Volcanoes, and
Mountains
Imagine this…
• Imagine that you are the first person on
Earth ever to experience an earthquake.
• What would you think was happening?
• What do you think might be causing it?
• How would you explain what happened?