Download The lithosphere: rocks and minerals

UNIT
Work in yo
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The lithosphere:
rocks and minerals
Rocks
Track 1
Where can we find rocks?
The geosphere is the mostly solid, rocky part of the Earth. It has three
layers.
• The inner most layer, called the core, is made up of metals.
• T
he middle layer, called the mantle, and the surface, called the crust,
are made up of rocks. The crust and the outer layer of the mantle
also form the lithosphere.
The rocks on the Earth’s crust
The crust is made up of solid rock and it is between seven and seventy
kilometres thick. Most of the rocks on the crust are on the seabed and
are covered by the oceans. The rest form continents and are usually
covered by forests, grasslands, crops and cities. Rocks also form large
mountain ranges and can be found as loose pieces. These loose pieces
are called blocks, gravel or sand.
Rocks: where they are found and their characteristics
rocks covered
by vegetation
crust
rocks on the
seabed
mantle
7 km
crust
mantle
core
Layers of the geosphere
4
rocks on the
surface
70 km
Unit
1
What is a rock?
Track 2
Rocks are materials that make up the Earth’s crust and mantle.
Rocks are a mix of one or various solid substances called minerals.
In nature, there are many different types of rocks. They can be
distinguished by looking at three characteristics.
• Composition. This is the mix of minerals that make up the rock.
Some rocks are made up of one mineral and others are made up
of various minerals.
• T
exture. This is the shape and the arrangement of the grains in
the rock. Sometimes, the grains are very small and regular. Other
times, they are irregular and contain fragments of other rocks.
• A
ppearance in nature. Rocks can be found in large mountain
ranges, in volcanoes and in parallel layers.
s
re
2 In your own words, explain what rocks and minerals are.
3 Look at the two rock samples below with a partner. Describe each
ck
Ro
sculpt
u
1 N
ame the three layers of the geosphere.
one and write down how they are different.
Rocks in parallel layers
Texture: fragments of
other rocks
Rocks in mountain ranges
Texture and composition: small and regular grains
of three minerals (quartz, orthoclase and mica).
5
Track 3
Minerals
Shape
fluorite:
bi-pyramid
Minerals are natural, solid substances
that make up rocks. There are many
types of different minerals. Each one
has got a mix of unique properties.
The properties of minerals
Minerals are identified by their physical
properties. The most important ones
are:
• Shape. Most minerals appear in
rocks as irregular grains or in sheets.
Sometimes, they have an almost
perfect geometric shape and are
called crystals.
• Lustre. Lustre is the way the
surface of a mineral looks when it
reflects light. It is described by its
resemblance to the lustre of other
materials such as metallic, pearly
and silky.
• C
olour and streak. The colour of
some minerals can be seen with the
naked eye. Sometimes, the surface
is dirty and we have to scratch it to
see the true colour. For this reason,
when describing minerals we usually
use the colour of the streak. This
is the colour when the mineral is
crushed to a powder.
1 W
hat are minerals?
2 What kind of properties are used to
identify minerals?
3 W
hat do lustre and streak mean?
Find out!
6
aragonite:
hexagonal prism
pyrite: cube
Lustre
gypsum: silky
rose quartz: glassy
galena: metallic
Colour and streak
hematite: grey or
red surface, red
streak
turquoise: blue
surface, white
streak
sulfur: yellow
surface, white
streak
Did you know...?
Quartz is one
of the most
common
minerals found
on, or in the
Earth!
Unit
1
Hardness
• Hardness. The hardness of a mineral is
how difficult or easy it is to scratch. The
more difficult it is to scratch, the harder the
mineral is.
The hardness of a mineral is calculated by
scratching it with other minerals on a scale
of hardness. Number ten on the scale is the
hardest mineral (like diamonds). Number
one on the scale is the softest mineral (like
talc).
• Density. Minerals that contain metals are
usually denser. For example, galena, which
contains lead, is a very dense mineral.
talc: very soft
quartz: very
hard
Density
pyrite: very
dense
sepiolite: not very dense
4 A
re the sentences True or False? Correct the false
ones in your notebook.
1 M
ost minerals appear in rocks as crystals.
2 Crystals have an almost perfect geometric
shape.
3 Lustre is the shape of a mineral.
4 Pearly and silky are examples of types of colour.
5 The streak is the colour of a mineral when it is
crushed.
6 Diamond is a very soft mineral.
7 Talc is a very hard rock.
!
ain
Use
5 a) What is density?
yo u br
r
b) How do we calculate the density of a solid
object?
6 A
nswer the questions in your notebook.
1 W
hy do we usually use the colour of the streak
when describing minerals?
2 Why is galena a dense material?
3 How do you know the hardness of a mineral?
diamond. Why do you think that is?
!
ain
Use
7 You need a diamond to be able to cut another
yo u br
r
Sci-find
esearch a specific mineral. Find
R
out the following information about
your mineral.
1W
here on the Earth is it found?
2H
ow is it created?
3W
hat are its properties?
7
Mined substances
Track 4
Extracting substances from the Earth’s crust
Deposits are areas of the crust where there are rocks, minerals and
other useful substances.
There are different ways to extract minerals from a deposit.
• Q
uarries or open pit mines are holes or cuts that are on or near
the surface.
• Underground mines are shafts, tunnels and galleries that are
deep inside the Earth.
• Drilling is when a deep hole is made. A pipe is then put in the
hole to extract gas or liquids, such as oil or water.
Extracting substances
Extraction in mines
Extraction by drilling
1 M
atch the sentence halves in your notebook.
1 Deposits are… a) … near the Earth’s surface.
2 Quarries or open pit mines are… b) …
deep in the ground.
3 Underground mines are… c) … when a pipe is put in a deep hole to
extract gas or liquids.
4 Drilling is… d) … areas where there are rocks, minerals
and other useful substances.
2 Listen to Freddie talking about his job and answer the questions.
Track 5
8
What is Freddie’s job?
Where in Spain does Freddie work?
Why does Freddie wear safety equipment?
What natural material does Freddie work with?
d
dergroun
Un
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2
3
4
mals
an i
Unit
Track 6
How do we use mined
substances?
1
Mined substances
clay
Building materials
Blocks of granite, limestone and basalt are
used to build walls. Sheets of slate are used
to make floors or roofs. Clay is used to make
pottery and other ceramic items.
granite
slate
Building materials
Decorative materials
Marble is used to make sculptures and
coatings for floors and walls. Some minerals,
such as diamonds, rubies and sapphires,
are used to make jewellery. They are called
gemstones.
gold
marble
Industrial materials
Cement is made by spraying and baking
clay and limestone. Glass is made from a
mineral called quartz. Metals are made from
minerals called metal ores. For example,
copper is extracted from chalcopyrite and
iron is extracted from hematite.
Energy sources
Coal, oil and natural gas are fuels that are
extracted from rocks. They are formed from
the organic remains of prehistoric plants
and animals. For this reason they are called
fossil fuels.
Uranium is a substance that is used in
nuclear power plants to make electricity. It is
extracted from a mineral called pitchblende.
rubies and diamonds
Decorative materials
cement
aluminium
copper
iron
glass
Industrial materials
natural gas
coal
petrol
Energy sources
3 Make a list of all of the substances mentioned in the text. Write
down a use for each one.
4 W
hat are fossil fuels and how are they formed?
5 W
hich mined substance is used to make...
1 ... electricity? 2 ... glass? 3 ... floors and roofs?
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Apply
your skills!
Project
Volcanoes
Volcanoes are mountains or hills that have an opening. When they
are active, ash, gas and hot magma escape from inside the Earth.
These eruptions can be spectacular but also dangerous!
atch the words to letters a-c.
1 M
1 ash
3 magma
b
2 eruption
a
2 Work in small groups to simulate a
volcanic eruption.
c
You will need:
•
•
•
•
10
a small wooden board
modelling clay
a small plastic bottle
red food colouring
• baking soda
• vinegar
• a cloth or paper towels (just
in case you need to clean up!)
Step 1
sing modelling clay, model the shape of a volcano. Make
U
it big enough to fit the plastic bottle inside! Then, put your
volcano on the wooden board.
Step 2
aint your volcano and your board. Use photos to help
P
you choose your colours and textures.
Step 3
ut off the top part of your plastic bottle and put it inside
C
your volcano.
Step 4
ut the vinegar and the red food colouring inside the
P
plastic bottle.
Step 5
inally, add a couple of teaspoons of baking soda to the
F
mixture and watch your volcano erupt!
Check what
you know!
ok
o
b
te
Work in your no
My Word list
Rocks
core/crust/mantle
geosphere
lithosphere
Minerals
1 Trace the picture below. Mark the crust, the mantle
and the inner and outer core.
colour
density
hardness
lustre
shape
streak
Mined substances
deposits
Uses of mined
substances
nswer the following questions in your notebook.
2 A
1 What are rocks made of?
2 What three characteristics distinguish rocks?
3 What are loose pieces of rock called?
3 a ) Find five mineral properties in the word snake.
pe
sh a
densitystreaklustr
eha
r d n ess
building:
• basalt/limestone
• clay/granite/slate
decorative:
• gemstones
energy sources:
• coal/fossil fuel/
natural gas/oil/
uranium
industrial:
• cement
• glass
• metal ores
b) Write a short definition for each property.
4 a) Name three substances we use to produce industrial
materials.
b) Name three substances used to produce energy.
c) Which are the best substances to make decorative
materials?
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