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The Geosphere
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THE GEOSPHERE
I n this unit, students will learn about the solid part of the Earth. It
is very important to highlight the link between the origin of our
planet and its layers, as well as the importance that minerals and
rocks have for humans and in our daily lives.
Competences and Objectives
KEY COMPETENCES
Linguistic communication (LC)
Mathematical competence and
key competence in science and
technology (MCST)
Sections
❚ Understand the origins of the
Earth.
Digital competence (DC)
Social and civic competence
(SCC)
❚ Identify minerals and their
properties.
Cultural awareness and
expression (CAE)
❚ Identify and classify rocks.
Sense of initiative and
entrepreneurship (SIE)
This unit can be worked on over a period of four weeks
(approximately twelve sessions). The number of sessions should be
determined by the interest that students show for the content, and
how the general unit planning takes place.
LEARNING OBJECTIVES
❚ Differentiate between the
layers of the Earth and
describe the characteristics
of the materials they are
composed of.
Learning to learn (LL)
Suggested Timing
❚ Value the importance of
minerals and rocks for humans
and of managing these
resources in a sustainable way.
❚ Carry out a research task.
N.° of sessions
Warmer
1
1. The Earth: origin and composition
1
2. Minerals
2
3. Rocks
3
4. The use of rocks
1/2
5. Extraction of minerals and rocks
1/2
Consolidation
1
Work and experimentation techniques
1
Final task
1
Self-assessment
1
Mixed-ability needs
In order to meet the needs of different students, a wide variety of
resources are offered as complements or alternatives to the work in
the unit: worksheets, lesson summaries and slide presentations with
core content and curricular adaptations.
It is at the discretion of the teacher that these resources are used,
although suggestions are given in every lesson.
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UNIT LESSON PLAN
Contents
The Earth: origin and composition
❚ The origin of the Earth
❚ Studying the Earth’s interior
❚ Layers of the geosphere
Assessment criteria
Learning outcomes
1. Understand the origins of the Earth.
1.1. Describe the formation process of the Earth.
(LC, MCST)
2. Relate the layers of the geosphere and its
formation processes.
2.1. Relate the layers of the geosphere and its
formation processes. (MCST, LL)
3. Differentiate between the layers of the Earth and
its characteristics.
3.1. Describe the main characteristics of the most
frequent materials in the external areas of the
planet and explain their distribution according to the
density. (LC, MCST, LL)
3.3. Describe the main characteristics of the crust,
the mantle and the core and the materials that
formed them. (LC, MCST, LL)
Minerals
❚ Properties of minerals
❚ The importance of minerals
❚ Sustainable management of mineral resources
4. Understand the concept of mineral and apply it to
recognise if certain substances are minerals or not.
4.1. Understand the concept of mineral. (LC, MCST)
5. Differentiate minerals according to their properties.
5.1. Identify minerals using information that could
differentiate them. (LC, MCST, DC, SCC)
6. Highlight the importance of minerals.
6.1. Describe some of the most frequent uses of
minerals in our daily life. ( MCST, DC, SCC)
Rocks
❚ Igneous or magmatic rocks
❚ Sedimentary rocks
❚ Metamorphic rocks
❚ The rock cycle
7. Understand the concept of rocks and their
classification.
7.1. Understand the concept of rock. (LC, MCST)
8. Differentiate rocks according to their origin.
8.1. Identify rocks using information that could
differentiate them. (MCST, SIE)
The use of rocks
9. Describe the most frequent use of rocks in our
daily life.
9.1. Describe some of the most frequent uses of
rocks in our daily life. (MCST, DC, CLL)
Extraction of minerals and rocks
10. Value the importance of minerals and rocks
for humans and of managing these resources in a
sustainable way.
10.1. Recognise the importance of minerals and
rocks for humans and of managing these resources
in a sustainable way. (LC, MCST, DC)
4.2. Apply the concept of mineral to recognise if
certain substances are minerals or not.
(LC, MCST, SCC)
7.2. Recognise the three types of rock according to
their origin and identify the main characteristics of
each one. (LC, MCST)
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The Geosphere
STUDENT RESOURCES
UNIT CONTENT MAP
Oxford investigation
>>>>>>
Interactive activities
>>>>>>
Talking book
>>>>>>
Video: The origin of the
Earth
Reading
comprehension:
The core of the Earth
rotates much slower
than you think
Web page: The quarry
Video: A Day without
minerals
Video: Lithium
for petroleum
Reading comprehension:
The rock of ages
Web page: Identifying rocks
Unit 3. The Geosphere
TEACHER RESOURCES
1. The Earth: origin
and composition
1.1. The origin of the
Earth
1.2. Studying the
Earth’s interior
1.3. Layers of the
geosphere
1.3.1. The Crust
1.3.2. The Mantle
1.3.3. The Core
Conceptual map
Presentation
2. Minerals
2.1. Physical properties of minerals
2.1.1. Optical properties
2.1.2. Mechanical properties
2.1.3. Magnetic properties
2.1.4. other properties of
materials
2.2. The importance of minerals
2.2.1. Metal ores
2.2.2. Raw materials for industries
2.2.3. Gems or precious stones
2.3. Sustainable management of
mineral resources
3. Rocks
3.1. Igneous or magmatic
rocks
3.2. Sedimentary rocks
3.2.1. Formation of
sedimentary rocks
3.2.2. Classification of
sedimentary rocks
3.3. Metamorphic rocks
3.4. The rock cycle
4. The use of rocks
Science practical:
The hardness of minerals
Reinforcement activities
>>>>>>
Curricular adaptation worksheets
>>>>>>
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>>>>>>
Oxford investigation
>>>>>>
Interactive activities
>>>>>>
Talking book
Web page: Gold extraction
and its use
Web page: The crust and its
matter.
5. Extraction of minerals and
rocks
Consolidation
Conceptual map
Presentation
Reinforcement activities
Work and laboratory
practical techniques
Extension activities
Curricular adaptation assessment
Assessment
3
Final task
Reinforcement activities
Extension activities
Curricular adaptation worksheet
>>>>>>
Reinforcement activities
>>>>>>
Curricular adaptation worksheets
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TEACHING SUGGESTIONS
3
THE GEOSPHERE
YOU WILL LEARN TO…
● Understand the origins of the Earth.
● Differentiate between the layers
of the geosphere and describe
the characteristics of the materials
they are composed of.
● Identify minerals and their
properties.
● Identify and classify rocks.
● Value the importance of minerals
and rocks for humans and of
managing these resources in a
sustainable way.
● Carry out a research task.
Final task
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The environmental impact of mineral extraction
bg1e900
Minerals are extremely useful to us. Minerals have great economic
value and are often obtained without thinking about the
environmental and social impact of their extraction.
What do you think the Earth is like in its interior? Could we
travel there?
What qualities make some minerals so appreciated by people?
Mineral extraction in third world countries is directly related to
smuggling, poor work conditions and child labour.
Rocks are used in construction. What else can rocks be used for?
One of the most sought after minerals is coltan, which is used to
the make parts of electronic devices. In this unit, you will research
this mineral and create a slideshow presentation.
Why do you think it’s important to manage mineral resources
responsibly?
What can you see in the photo? Where do you think it is?
3. The geosphere
A
t the beginning of the unit, the objectives are already
established and they should be linked to the learning
outcomes. Students will have a clear idea about the topics
as well as what they will learn throughout the unit.
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The main qualities are the hardness, the lustre and the colour as
well as the transparency.
Rocks are used for construction.
❚ What else can rocks be used for?
Before playing the video, ask questions so that the students can
think about them while watching it. It is a very useful way to
check if students understood the explanations that appear in the
video.
Rocks also have ornamental uses and can be used as fossil fuels
or as a source of minerals for technological uses.
Superficial extractions are more profitable than subterranean
extractions.
❚ Why do you think it’s important to manage mineral
resources responsibly?
Video: LITHIUM FOR PETROLEUM
The video is about the materials extracted from the geosphere
and the use of them nowadays in developed countries. Play until
minute 4:50.
Because superficial extractions have a great impact on the
environment, killing all living things in the area.
After watching the video, discuss the following and elicit answers
from the students.
❚ What can you see in the photo? Where do you think it is?
Jules Verne, in his book called Journey to the centre of the Earth,
explains how the interior of the Earth was.
PRESENTATION
Use the slideshow presentation to show the different sections in
the unit and to evaluate student’s prior knowledge. This tool can
also be used as revision at the end. The slides can stimulate student
participation, as they can be asked about certain topics before they
study them.
❚ What do you think the Earth is like in its interior? Could
we travel there?
No, because the temperature and the pressure in the interior of
the Earth are unbearable to humans.
Minerals are widely used for jewelry as precious stones after a
process of cutting and polishing.
Point out the Final task to the students: The environmental impact
of mineral extraction. Explain what the task is: an oral presentation
with slideshows and in groups.
❚ What qualities make some minerals so appreciated by
people?
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meaning of the words and write them down in their notebook
in alphabetical order, thus creating a scientific glossary. Thus
students will have exposure to the vocabulary and will be more
prepared to start the unit.
Read the task with students and explain that the steps to carry out
the final task are on page 65.
By carrying out the final task you will be working the following
key competences:
❚ Linguistic communication (LC). In the oral presentation that
will take place in the classroom.
CONCEPTUAL MAP
To introduce the contents of the unit, you could show an
incomplete conceptual map and ask them to complete the gaps
in their notebook or orally with the whole group. This will help
students to visualise the links between the different contents of
the unit.
❚ Mathematical competence and basic competences in
science and technology (MCST). Throughout the unit.
❚ Digital competence (DC). When searching for information.
❚ Learning to learn (LL). When following a study technique
which helps the learning process.
OXFORD INVESTIGATION
❚ Sense of initiative and entrepreneurship (SIE). When
students decide by themselves which information is useful for
their work.
It starts with an introduction of the unit with some preliminary
questions and the final task that should be carried out after
finishing the activities. The final task is normally a practical problem
whose solution demands a variety of learning skills and research.
Students will be given the idea that in particular activities they will
learn concepts and/or the procedures that will be used to sort out
the practical problem.
❚ Social and civic competences (SCC). When participating in
group work.
In the first session you could introduce the vocabulary suggested
in the section Study skills on page 63. Students search for the
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1. THE EARTH: ORIGIN AND COMPOSITION
1.3. Layers of the geosphere
The Earth is the third closest planet to the Sun. It is a rocky planet and the only planet
that has water in all three states. As a result, it is the only planet with living things.
The solid part of the Earth is divided into different layers separated by areas
known as discontinuities. In these areas the seismic waves change velocity. This
allows us to identify where each layer ends.
The Earth can be divided into four layers: the geosphere or solid layer; the
atmosphere or gaseous layer; the hydrosphere which contains water in all three
states and the biosphere where life exists.
1.3.1. The crust
This is a thin layer covering the Earth’s surface and it
is the least dense layer. There are two types of crust:
1.1. The origin of the Earth
❚ The continental crust is more than 1 000 million
years old and it is between 10 and 70 km thick.
The continental shelf, continents and islands are all
part of the continental crust. It is composed of rocks
such as granite, clay and slate.
According to the latest studies, 4 600
billion years ago the Sun formed from
chemical reactions in a giant cloud of
dust and gas, called a nebula. In the
cloud of matter that surrounded the
Sun, smaller dust particles collided and
grew in size. This process which formed
the planets is called accretion of
planetesimals.
❚ The oceanic crust is 200 million years old and it is
between 6 and 10 km thick. It forms the seafloor
and is composed mainly of basaltic rock.
1.3.2. The mantle
For 1 000 million years the Earth was
incredibly hot. Due to the immense
heat stored in the Earth’s interior, there
was a lot of volcanic activity during
this period. As the Earth’s temperature
decreased, gravity pushed denser
materials, such as iron, towards the
Earth’ s interior. Less dense materials,
such as oxygen, moved towards the
Earth’ s surface. This process is called
density differentiation. As the Earth
cooled, it maintained this structure of
layers.
The density of this layer varies. It is composed
mainly of a type of rock called peridot. The mantle
has two parts.
❚ The upper mantle has a higher density than
the crust and it is solid. However, scientists have
discovered some areas of liquid or molten rock.
❚ The lower mantle is the densest layer of the
mantle and contains materials in a solid state.
1.3.3. The core
1.2. Studying the Earth’ s interior
This is the most internal and densest layer of the
geosphere. It is composed mostly of iron, although
other metals such as nickel can be found. It is divided
into two layers.
The Earth’s is 6 370 km at the Equator but we only have direct knowledge of the
most superficial layers under the Earth’s surface. Mines or drill holes1 have allowed
us to reach depths of 8-12 km.
❚ The outer core is not as dense as other layers. It is
composed of molten materials and it is constantly
moving.
To understand the composition of the Earth’s interior, scientists have to use indirect
methods. The most common method is the study of earthquakes called the seismic
method. This method analyses the energy generated by earthquakes.
❚ The inner core has the densest materials. It is the
hottest layer. Even though the temperatures are so
hot, the materials in this layer are in a solid state due
to the immense pressure found in it.
Formation of the Solar System
drill hole: a perforation in the
ground in order to study the rocks
under the Earth’ s surface
1
When you throw a pebble into water, the water moves across the surface in
all directions in waves. Similarly, when an earthquake occurs, the movement
generates waves of energy that travel to the interior of the Earth, called seismic
waves. These waves can be detected by an apparatus called a seismograph.
This shows us that the speed of the waves vary as they pass from one layer to
another.
Key concepts
Understand
1.
Explain in your own words the meaning of accretion of planetesimals.
2.
Listen and find the parts of the geosphere on the diagram.
Create
The study of the data obtained from seismographs has allowed scientists to deduce
the composition of the Earth’s interior. This information has been used to create a
model of the Earth’s structure. It is divided into three layers: the crust, mantle and
core.
Seismograph
Layers of the geosphere and discontinuities that separate them
3.
Find out about the density of the layers of the geosphere. Make a table
with the information in the order of least dense to densest materials.
❚ The Earth formed by the
process of accretion of
planetesimals. The materials
that make up the Earth
were distributed in layers
according to their density.
❚ There are three layers in
the geosphere: the crust
(continental and oceanic),
mantle (upper and lower)
and the core (outer and inner).
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3. The geosphere
1. The Earth: origin and composition
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water as well as in its interior and the same process happen to the
waves produced by the earthquakes. Light waves are deflected when
they pass from air to water and it makes us see a stick in the water
as if it was crooked. The same happens to the seismic waves when
they are deflected from one place to the other. Those deflections
affect the speed of the wave transmission through the interior of the
layer. This way, and also because of the seismographs, we are able to
know the internal structure of the planet.
Before or after reading each section, listen to the Talking book.
1.1. The origin of the Earth
Before starting this section, remind students about the concepts
of density and gravity. It will help them to understand clearly the
origin of our planet.
It is important that students differentiate the concepts of density
and mass. Otherwise, they will not be able to understand the
process of density differentiation. You can take a scale to the
classroom, a small pebble and a big cork. Make sure the cork
weighs more than the pebble. Put the cork and the pebble in a
bow with water and ask them to observe what happens. The cork
will float and the pebble will sink. This is a practical and visual way
to understand the difference between these two concepts.
On the planet there are lots of network seismographs to detect any
earthquakes that could happen in the crust. At least three seismographs
are needed to precisely detect the epicenter of an earthquake.
1.3. Layers of the geosphere
A practical way to explain the layers of the geosphere is to make
a chart where students can compare depth, density, state of the
materials and its composition. This chart will help students to easily
follow the explanations and understand the contents
Show the video.
Layers of the
geosphere
Video: THE ORIGIN OF THE EARTH
This video is about how the planets were formed. The presentation of the video and the answers to the questions will help students to deepen their understanding of the following question:
After hearing about the Big Bang theory about the formation of
the universe, how do you think the Earth was formed?
Depth
Density Physical state Composition
Crust
Continental crust
Up to 70 km
2,7 g/cm3
Solid
Granite, clay...
Oceanic crust
Up to 10 km
3 g/cm
Solid
Basalt
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Mantle
1.2. Studying the Earth’s interior
For students it is always a mystery to know the interior of the
Earth without being there. They should understand that the waves
produced by an earthquake are the same as the ones when you
throw a pebble into a pond. Those waves travel on the surface of the
Upper mantle
Up to 670 km 3,3 g/cm3
Solid
Peridot
Lower mantle
Up to 2900 km 5,5 g/cm3
Solid
Peridot
Outer core
Up to 5120 km 10,6 g/cm3
Liquid
Iron
Inner core
Up to 6370 km 13 g/cm
Solid
Iron
Core
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2.
The seismographs detect the variations of the seismic wave’s
velocity that are related to the discontinuities. These discontinuities
are named according to the person who discovered them. Only
the outer core is liquid, although by analysing how the seismic
waves move, we can deduce that in the mantle there are materials
partially molten that reduce the velocity of the waves. In the chart
we only see the main materials but students must know that
there are other materials, especially in the crust. They will study
those in this unit
3
Listen and find the parts of the geosphere on the
diagram.
The layers of the geosphere are divided according to their
composition. There is another division according to their conduct
or dynamism. It says that the geosphere is divided into: lithosphere
(the crust and part of the upper mantle), sub-lithospheric mantle
(rest of the upper mantle), lower mantle, outer core and inner core.
When explaining the mantle, highlight that the materials partially
molten and the high temperatures generate movements called
convection currents. Those movements move the lithospheric
plates.
The core generates a magnetic field that allows us to find
directions using a compass and also protects us from harmful
solar radiations.
Finish the section by asking them to do questions 1 to 3 and then
review the Key concepts at the end of the section.
Tips: Question 1 should be done with the whole class. Before
question 2 give the students time to look at the diagram first, then
play the audio twice. Ask students to do question 3 individually
and then ask them to compare their answers. Correct with the
whole class.
a)
The crust.
Reading comprehension: THE CORE OF THE EARTH
ROTATES MUCH SLOWER THAN YOU THINK
b)
The oceanic crust.
c)
The upper and lower mantle.
This text is to emphasise the impact that the core movements
have on the rest of the planet. The core is not a static or constant layer; it moves and grows slowly but continuously. The core
movements are very important for the planet, for example, in the
creation of a magnetic field.
d)
The core.
Audio script:
Curricular adaptation: 1. LAYERS OF THE GEOSPHERE
Section adapted according to the curriculum.
This is the least dense layer.
b)
This is 200 million years old.
c)
The mantle has two parts, what are they?
d)
This is the densest layer of the geosphere.
Create
3.
Answer key
Understand
1.
a)
Find out about the density of the layers of the
geosphere. Make a table with the information in the
order of least dense to densest materials.
The continental crust has an average density of 2.7 g/cm3,
while the oceanic crust has a higher density, with an average
of 3.0 g/cm3. Consequently, the layers of the geosphere from
the least to the more dense are:
Explain in your own words the meaning of accretion
of planetesimals.
Process which formed the planets. Billions of years ago the
Sun formed from chemical reactions in a giant cloud of dust
and gas (nebula) and in the cloud of matter that surrounded
the Sun, smaller dust particles collided and grew in size.
Continental crust (2.7 g/cm3) - Oceanic crust (3.0 g/cm3)
- Upper mantle (3.5 g/cm3) - Lower mantle (5.6 g/cm3) - Outer
core (9.9 g/cm3) - Inner core (13.0 g/cm3).
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2. MINERALS
2.1. Physical properties of minerals
Minerals and rocks form part of the Earth’s crust. Since ancient times, humans
have used minerals obtained from the Earth.
In nature there are more than 4 000 known minerals. We can identify some minerals
by studying their physical properties, without analysing their chemical composition.
Physical properties are classified into optical, mechanical and magnetic.
Minerals are solid, inorganic, natural materials. They have a definite chemical
composition and usually have a crystalline structure.
2.1.1. Optical properties
A mineral’s optical properties relate to how a mineral reacts to light.
In order to understand the definition of minerals we will analyse the description
term by term.
❚ Minerals are solid substances. They cannot be liquid or gaseous at room
temperature. This is why mercury is not considered a mineral.
❚ Habit: some minerals have very characteristic shapes
that reflect their crystalline structure. For example,
pyrite has cubic shapes and aragonite has hexagonal
shapes.
❚ They are inorganic. They have not been produced by living things, unlike pearls,
shells or amber.
❚ They are natural. This means they have not been made by humans, like plastic or glass.
galena
❚ Streak: is the colour of the powder produced when a
mineral is scratched. The colour of the streak does not
have to be the same as the mineral. For example, solid
quartz can be many different colours, but its streak is
always white.
❚ They have a definite chemical composition. They are composed of chemical
elements that are always combined in the same proportion to create the same
mineral. For example, galena, is a mineral formed by two chemical elements:
sulphur and lead.
❚ They have a crystalline structure. This means that the particles are arranged to
form a geometric structure that is repeated constantly. For example, the atoms
of galena are structured to form a cubic shape.
Pyrite
If the arrangement of the mineral particles are visible, we call this a crystal.
Crystals need enough time and space to form. In a crystal we can identify the
edges, flat faces and the vertices of its geometrical shape.
Aragonite
❚ Colour: some minerals have a very characteristic
colour. Galena is rusty grey and sulphur is bright
yellow. Other minerals, like quartz, can be found in
different colours, as seen in the images below.
Galena and its streak
❚ Lustre: describes how the mineral reflects light. It can
be metallic if it shines like metals, glassy if it is like
glass, pearly, if it shines like a pearl, diamond-like, or
dull if it doesn’t shine.
Crystallisation of minerals
Crystalline structure of minerals
Remember
4.
Blue quartz
Transparent quartz
Pink quartz
Sulphur
Metalic: magnetite
Glassy: fluorite
Pearly: gypsum
Write a list of the characteristics of minerals in your notebook.
Understand
5.
Look at the two pink quartz roses above. Explain which one had more
space and time to form.
6.
Look at the photo of galena above. Can you say that it is a crystal?
7.
Explain why amber is not a mineral.
8.
Would you classify factory-made diamonds as minerals?
9.
Is water a mineral? Explain your answer.
Create
Diamond-like: rutile
Dull: limonite
Understand
10. Look for the definition of mineraloide. Decide if the glass in a window
is a mineral or a mineraloide and explain your answer.
11. Explain the difference between the colour and the streak of a mineral.
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3. The geosphere
2. Minerals
10. Ask students to do this individually, then pick up a few
of their notebooks and randomly read the definitions out
loud. Students can vote on the most accurate definition.
Include the answer as one of the possibilities. The diagram
in the margin on page 50 should help them understand.
Ask the students: How do you differentiate a mineral from a rock?
At this stage, students tend to mix up the concepts of mineral and
rock. Highlight that minerals are the materials that make up rocks.
Show them a granite rock. Explain that granite is a rock but the
different colors on it are the minerals that actually formed it. Ask
them again the meaning of mineral and rock and make sure they
all understand the difference between these two concepts.
2.1. Physical properties of minerals
Ask students How can we distinguish one mineral from the
other? Explain that the physical properties of minerals help us to
distinguish one from the other. Tell them to read the text and look
at the images. Then ask them to do question 11.
When you talk about the definite chemical composition, emphasise
that there are some minerals that are formed by only one single
chemical element such as sulphur, gold and silver. These are called
native minerals. Students should now do activities 4 to 10. Below
you will find suggestions for each activity.
4.
Ask students to do this on their own and then compare
answers.
5.
Ask students to compare the two images in groups and
then write the answers on the board.
6.
Do this as a whole group activity.
7.
Write various possible answers on the board and ask
students to choose the correct one.
8.
Ask students to do this quickly in groups of three and elicit
answers.
9.
Ask students to do this in pairs and then to compare their
answers with another pair before asking a spokesperson
from each group to answer.
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11. Do this activity with the whole class, then write the answer
on the board and ask students to copy it.
Answer key
Remember
4.
Write a list of the characteristics of minerals in your
notebook.
Minerals are solid, inorganic, natural minerals. They have a
definite chemical composition and usually have a crystalline
structure.
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A mineraloide is a solid substance, natural material, and
inorganic. It has a definite chemical composition and similar
mineral characteristics but without a crystalline structure.
Its particles are not organised as they are in minerals and a
mineraloide does not have a geometrical shape. It is so called
non-crystalline. The glass in a window is a mineraloide or an
amorphous substance.
Understand
5.
Look at the two pink quartz roses. Explain which one
had more space and time to form.
The pink quartz on the left was probably developed with
more space and time as we can appreciate with a naked eye
that it is more compact. The crystal has edges, vertices and
more defined and appreciable flat faces.
6.
Understand
Look at the photo of the galena above. Can you say
that it is a crystal?
11. Explain the difference between the colour and the
streak of a mineral?
Yes, because it has a crystalline structure and a cubic shape.
7.
8.
Explain why amber is not a mineral.
A streak is the colour that is produced when a mineral is
scratched, it does not have to be the colour of the mineral.
Basically, amber is not a mineral because it is not inorganic.
That means that it was produced by a living thing and
consequently is a petrified or fossilised vegetal resin.
Laboratory practical: THE HARDNESS OF MATERIALS
This laboratory practical is a good way to motivate students and
it will probably make them more interested in the contents that
will be seen during this unit. By doing it, students will become
familiarized with a couple of minerals and also will have a clear
idea of the concept of hardness.
Would you classify factory-made diamonds as mineral?
Factory-made diamonds do not have a natural origin, they
are made by human beings and are not minerals.
9.
3
Is water a mineral? Explain your answer.
Water in liquid state is not a mineral. But in solid state, as in
ice cubes, and with the condition that a human being has not
intervened in its formation, it is considered a mineral by the
majority of scientists, although there is always a controversy
about this theory.
Web page: THE QUARRY
Minerals are solid and part of the rocks. These are extracted from
the interior of the crust. On this web page, students will learn
more about the properties of minerals and also identify some of
them.
Create
10. Look for the definition of mineraloide. Decide if the
glass in a window is a mineral or a mineraloide and
explain your answer.
Curricular adaptation: 2. MINERALS
Section adapted according to the curriculum.
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2.2. The importance of minerals
2.1.2. Mechanical properties
Throughout history, the ability to identify minerals and to obtain raw materials has
been essential to the success of civilizations.
The mechanical properties of minerals refer to how the mineral behaves
when a force is applied to its surface.
Mohs scale
Hardness
Mineral
1
Talc
2
Gypsum
3
Calcite
4
Fluorite
5
Apatite
6
Orthoclase
7
Quartz
8
Topaz
9
Corundum
10
Diamond
Characteristics
Very soft, because it can be scratched by another
mineral.
Today, minerals are used mainly as metal ores, as raw materials for industry, or sold
as gems or precious stones.
❚ Hardness describes a mineral’s
resistance to scratching. To check if
a mineral is harder than another, we
can scratch one with the other. The
mineral that is scratched is softer than
the mineral that scratches it.
Soft minerals that can be scratched by the point of
a knife.
Hard minerals. Orthoclase can be scratched with
sandpaper and quartz scratches glass.
Very hard, cannot be scratched by any other
mineral.
2.2.1. Metal ores
These are minerals that metals are extracted from (see table on the right). Other
minerals known as native or noble minerals are found in nature in their pure
state. Examples of these minerals are gold, silver or platinum, admired since ancient
times for their colour, beauty, easiness to mould and durability.
We can use minerals that are listed on
the Mohs scale to identify hardness.
This scale grades the hardness of 10
minerals from 1 to 10. The softest
mineral, Talc (1) can be scratched by
all the others. At the other end of the
scale, diamond (10) can scratch all
the other minerals and can only be
scratched by another diamond.
2.2.2. Raw materials for industry
These are the most abundant minerals found in the Earth’s crust. Some examples are:
uraninite which provides us with uranium used as fuel in nuclear power stations;
quartz, which is very important for manufacturing glass, computer components,
parts and solar panels; and gypsum, which is used for manufacturing plaster,
alabaster, fertilisers and explosives.
Metal
Aluminium
Blende
Zinc
Chalcopyrite
Tin
Cinnabar
Mercury
Galena
Lead
Hematite
Iron
Main ores of some metals
2.2.3. Gems or precious stones
❚ Cleavage describes the way a mineral breaks. Many minerals break to show flat
surfaces, maintaining the crystalline structure. For example, galena breaks into
cubic shapes and gypsum breaks into sheets.
These are beautiful and rare minerals which have a great economic value. They are
used for jewellery, usually after a process of cutting and polishing to bring out their
lustre. Some of the most well-known gems are diamonds, rubies, sapphires and
emeralds.
❚ Tenacity describes how easily a mineral breaks. A fragile mineral breaks easily,
such as talc.
Gypsum
Ore
Bauxite
Some minerals can be pulled into thin threads. This is the case of copper threads
that conduct electricity. This is called ductile tenacity.
2.1.3. Magnetic properties
Some minerals, such as magnetite, behave like a magnet. They attract objects
that contain iron and nickel.
Magnetite
Diamond
2.1.4. Other properties of materials
❚ Transparency describes how a mineral reacts to light. A mineral can be
transparent, such as diamond, when light can pass through it; translucent,
like quartz, when light passes through it but is distorted; or opaque, like
galena, when no light can pass through.
Quartz
Galena
Sapphire
Emerald
Uncontrolled mining has an impact on the environment such as contamination of
water and land contamination with metals. It can also cause health problems for
miners: headaches, blood poisoning with lead and mercury, and breathing problems.
❚ Density is the relation between the mass and volume of a mineral (density
= mass/volume). Density is usually measured in grams per cubic centimetre
(g/cm3). This property is specific to each mineral and is independent of size.
So, the density of a mineral is important information for identifying minerals.
Responsible use of minerals is essential to avoid or reduce this negative impact. We
can help by recycling minerals and electronic devices made with minerals such as
mobile phones and computers.
Understand
Analyse
12. Explain in your own words what the Mohs scale is? What is it used for?
15. Find out about the use of the metals extracted from these mineral
ores: bauxite and cinnabar. Write a short report in your notebook.
13. A crystal is hit and breaks into small cubes. What property does this describe?
16. Find out about the hardness of the gems in the photos above. Do you
think their economic value is related to their hardness? Explain your
answer.
Analyse
14.
Ruby
2.3. Sustainable management of mineral resources
Listen and say which mineral properties are being described.
Key concepts
❚ Minerals are solid, inorganic
substances of natural origin.
They have a definite chemical
composition and most have a
crystalline structure.
❚ They have properties that
allow us to identify them
such as hardness, lustre,
streak or density.
❚ They are used as metal ores,
as raw materials for industry
and as gems or precious
stones.
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2.1.2. Mechanical properties
53
Video: A DAY WITHOUT MINERALS
Ask students to read the text and look at the table illustrating
Mohs Scale.
This video shows some daily objects that are manufactured with
minerals. After watching the video twice, ask the students to
answer the questions given in the worksheet. To finish the activity,
ask students: What do we use minerals for nowadays?
Ask the students to re-read the text and identify three mechanical
properties (hardness, cleavage, tenacity). Then ask them what the
other properties are: magnetic (not all minerals), transparency and
density.
Finish the section revising the Key concepts at the end of
the section and also remind them about the Final task that
they should do about the environmental impact of mineral
extraction.
Students should now do questions 12 to 14.
Tips: For question 12, ask the students to look at the scale
in pairs, and to decide not only what it is measuring but why
this would be useful: Brainstorm ideas on the board. For
question 13, do this activity quickly with the whole class, then
ask students to think of other quiz-type questions to identify
another property.
Curricular adaptation: 3. PROPERTIES OF MINERALS
Section adapted according to the curriculum.
For question 14, play the audio at least twice. The second time,
stop after each sentence and elicit the answer.
Answer key
Now ask students to do questions 15 and 16. They can do this
as homework, or if they access to reference material (digital or
otherwise), they could do it in class. Ask them to discuss their
findings before handing in their report.
Remember
12. Explain in your own words what the Mohs scale is?
What is it used for?
2.2. The importance of minerals
Once students internalise the definition and the properties
of minerals, it should be easier for them to understand their
importance and the sustainable management of mineral
resources.
It is a scale that measures the hardness of minerals. Hardness
is not a quantitative property so that is the reason the Mohs
scale is so useful to classify minerals and their uses.
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13. A crystal is hit and breaks into small cubes. What
property does this describe?
Metals extracted from these minerals are, in the following
order: aluminium, mercury and zinc. Aluminium and zinc are
very useful to produce metal tools and utensils. Mercury is
used to make thermometers because of its high capacity of
dilation.
In this case, we are talking about cleavage, because it keep
the crystal shape. To be precise, we call it cubic cleavage.
14. Listen and say which mineral properties are being
described.
16. Find out about the hardness of the gems in the photos
above. Do you think their economic value is related to
their hardness? Explain your answer.
Audio script and answers:
a)
3
This is how easily a mineral breaks. (tenacity)
b)
This is the relation between mass and volume.(density)
c)
This is the way a mineral breaks.(cleavage)
d)
This is how a mineral reacts to light.(transparency)
Diamond
Analyse
Ruby
Sapphire
Emerald
The hardness of these gems or precious stones are equal or
superior to 8. Their economic value is related to their colour,
brightness, natural beauty and also their hardness and
durability over time.
15. Find out about the use of metals extracted from these
mineral ores: bauxite and cinnabar. Write a short report
in your notebook.
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3. ROCKS
3.1. Igneous rocks
In some areas of the upper mantle, minerals melt due to high temperatures.
Rocks are natural aggregates made up of one or various different minerals.
Magma is a substance made up of melted materials mixed with gases and
water, formed in the Earth’s interior.
Rocks, like minerals, have properties that allow us to identify them, for example,
composition and texture.
When magma rises to the surface it can remain in the crust or it can exit to the
exterior. In both cases, away from the source of heat, magma cools until it becomes
solid and forms igneous rocks or magmatic rocks.
❚ The composition of a rock refers to the minerals that make up the rock.
Some rocks only have one mineral. For example, limestone is composed only
of calcite. These rocks are called simple or homogeneous rocks. Others are
made up of a variety of minerals. For example, granite is made up of quartz,
feldspar and mica. These rocks are called complex or heterogeneous
rocks.
These rocks are made up of one or several minerals compressed together, so they
are extremely compact. The resistance of igneous rocks to pressure makes them a
perfect material to construct buildings.
There are exceptions such as petroleum and coal, which are not of mineral
origin as they come from animal remains and so do not contain minerals.
Igneous rocks are classified as volcanic or plutonic depending on where they were
formed.
❚ Texture refers to the size and arrangement of the minerals in the rock. It is not
always possible to observe the texture of a rock without using a magnifying
glass or even a microscope.
❚ Volcanic igneous rocks or extrusive rocks are formed when magma rises and
leaves the Earth’s crust as lava. Lava cools quickly and forms volcanic rocks.
These instruments allow us to identify the minerals that make up rocks. For
example, without a magnifying glass granite appears to have different colours:
greys, whites and blacks. With a magnifying glass we can see that it is made up
of crystals of quartz (greys), feldspar (whites) and mica (blacks).
quartz
Understand
17. Explain the difference
between homogeneous
and heterogeneous rocks.
Why are coal and petroleum
exceptions?
18.
Listen and identify the
rocks: igneous, sedimentary
or metamorphic.
Analyse
19. Study the photo. What
type of rock is a
conglomerate?
Is it homogeneous or
heterogeneous? Explain
your answer.
Obsidian is shiny black
and originates in the
continental crust. It has a
glassy texture. The crystals
have not had time to
form.
mica
feldspar
Composition and texture of granite
There are many ways of classifying rocks, but geologists prefer to classify
them according to their origin. Rocks can be metamorphic, igneous or
sedimentary.
Pumice or pumice stone
is a continental rock. It is
easily recognised because
of the many small holes
in the surface. These were
formed by gases that
were in the rock before it
solidified.
Basalt originates in
submarine volcanoes.
It contains very small
minerals due to its rapid
cooling. It is the most
abundant rock found in
the Canary Islands and
the ocean floor.
❚ Plutonic igneous rocks or intrusive rocks are formed when rising magma
cools slowly inside the Earth’s crust. The mineral crystals are easily visible as they
had more time to form.
Types of rocks
Igneous
Sedimentary
Metamorphic
These originate when
magma from the
Earth’ s interior cools
and solidifies.
Sediments are
fragments of other
rocks, minerals and
organic remains.
Sedimentary rocks
form when sediments
consolidate.
Formed by the
transformation of other
rocks subjected to high
pressure conditions
and/or temperatures,
without reaching a
melting state.
Conglomerate
Understand
Granite is the most
Syenite is a continental
abundant plutonic rock on plutonic rock.
the continental crust.
Gabbro is a plutonic rock
found in the ocean’s crust.
20. Explain why crystals in
the minerals that make
up plutonic rocks are
visible, but are not visible
in the minerals of volcanic
rocks.
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3. The geosphere
3. Rocks
Curricular adaptation: 4. ROCKS
Start this section by showing the different types of rocks. This
is a good opportunity to review the differences between rocks
and minerals just to make sure all the students understood these
concepts. Students can look for the variations between the
different types of rocks. To help them you could use the following
chart by copying it on the board and filling it in with the whole
class:
Rock
55
Density
Visible
sediments
Visible
minerals
Section adapted according to the curriculum.
3.1. Igneous or magmatic rocks
Igneous or magmatic rocks are the ones that originated from the
solid magma, in the interior or the exterior of the crust. At this
point, you can highlight the difference between magma and lava.
Magma is formed in the Earth’s interior while the lava is in the
Earth’s exterior.
Aligned
minerals
Now students can do question 20. Ask students to do this individually, and then write various answers on the board ( some
incorrect), then ask the students in groups to choose the correct
answers.
Ask students about the concepts of composition and texture of rocks.
You can add two more columns to the chart (one for composition
and one for texture) and students should copy it in their notebook
and complete it as they work through the unit.
Curricular adaptation: 5. TYPES OF ROCKS
Section adapted according to the curriculum.
The practical activity about The texture of rocks on page 64 will help
students to clearly understand these concepts.
There are many ways of classifying rocks, but geologists prefer to
classify them according to their origin. Rocks can be metamorphic,
igneous or sedimentary.
Answer key
Understand
Now students could de questions 17 to 20.
17. Explain the difference between homogeneous and
heterogeneous rocks. Why are coal and petroleum
exceptions?
Tips: Before doing question 17, check that students understand
the meaning of homogeneous and heterogeneous in other
contexts. For question 18, play the audio at least twice. The
second time, stop after each sentence and elicit the answer. For
question 19, ask students to do this in pairs.
Homogeneous rocks only have one mineral, for example,
limestone that is composed only of calcite. On the other
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hand, heterogeneous rocks are made up of a variety on
minerals. For example, granite is made up of quartz, feldspar
and mica. Coal and petroleum are exceptions because they
are not of mineral origin.
A conglomerate is a sedimentary rock that is clearly visible. It
is made up of other rocks as well as sediments. Fragments of
a heterogeneous rock are visible and distinguishable with the
naked eye.
18. Listen and identify the rocks: igneous, sedimentary or
metamorphic.
Understand
Audio script and answers:
20. Explain why crystals in the minerals that make up
plutonic rocks are visible, but are not visible in the
volcanic rocks?
a) These are formed when rocks are subjected to high
pressure conditions. (metamorphic)
b)
These originate when the magma cools. (igneous)
c)
These form when sediments consolidate. (sedimentary)
3
Because plutonic rocks are formed during a very slow process
so mineral crystals have more time to form. On the other
hand, volcanic rocks are formed when magma rises and
leaves the Earth’s crust as lava. And lava cools quickly so there
is no time for the crystallisation.
Analyse
19. Study the photo. What type of rock is a conglomerate?
Is it homogeneous or heterogeneous? Explain your
answer.
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3.2. Sedimentary rocks
3.2.2. Classification of sedimentary rocks
Rocks found on the Earth’s surface are changed by the action of the wind, sea,
rivers, rain or ice. The elements wear down rocks in a process of erosion. The rock
fragments are deposited in the lowest areas of the Earth’s surface.
These rocks are classified by looking at the origin of the sediments that compose
them. Sedimentary rocks can be detrital or non-detrital.
❚ Detrital sedimentary rocks are made up of other rocks. Depending on the
size of the fragments or grains that compose them, we can distinguish various
types.
❚ Sediments are fragments of rock and organic material that have been
transported and deposited by water and wind.
❚ The places where sediments are deposited are called sedimentary basins.
Conglomerates contain
grains that are more
than 2 mm big, called
clasts. Clasts are joined
together by smaller
grains.
Sandstone contains
grains smaller than
2 mm that are easily
visible. It feels rough to
the touch.
Clay is made up of very
small grains that can
only be observed with
a magnifying glass or a
microscope. It is soft to
the touch.
❚ Non-detrital sedimentary rocks are not made up of fragments of other rocks.
They are made up of sediments from skeletons of marine life or mineral salts. They
can also come from the remains of living things that have not decomposed.
Sedimentary basins: the origin of sedimentary rocks
The process in which sediments transform into sedimentary rocks is
called diagenesis or lithification.
3.2.1. Formation of sedimentary rocks
Limestone can contain
fossil remains or be composed
of mineral salts. It produces
effervescence in contact
with acids.
Sediments deposited in sedimentary basins (1) often follow two essential
processes for the formation of sedimentary rocks:
❚ Compaction (2) is when sediments lose volume. Due to the weight
of the sediments on top, water is lost and the sediments become
compacted.
❚ Cementation (3) takes place after the water is lost and the salts form
crystals. The crystals act like cement and stick the sediments together
to form sedimentary rocks.
Formation of sedimentary rock
Gypsum is a rock composed
of the mineral of the same
name, gypsum. It originates
from the salts of water
evaporation in shallow2 lakes
and seas.
Coal forms from the
accumulation and
decomposition of plant
remains over millions
of years.
Coal and petroleum originate from the remains of living things that have not
decomposed. They can burn and produce energy. This is why they are called
combustible fossils. Coal originates from plant remains that could not decompose
completely because they were buried in sediments and sand. Petroleum is the
result of the transformation of remains of marine microorganisms buried in the
ocean floor.
Analyse
21. 2.5 cm of sediments are accumulated every 10 years in a
sedimentary basin. After the process of compaction, will
the volume of sediment be thicker or thinner? Explain your
answer.
Petroleum also results
from the transformation
of organic remains. It is
considered a rock even
though it is not in a solid, but
liquid state.
2
shallow: not deep
Analyse
22. Explain why water is important in the formation of sedimentary
rocks.
23. Can you explain why limestone, which contains remains of living things,
cannot be burned like coal or petroleum?
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57
3.2. Sedimentary rocks
3.2.2. The classification of sedimentary rocks
Before starting with sedimentary rocks, clarify the definition of
sediments, sedimentary basins and diagenesis.
Tell students to read the text and to look at the different rocks.
Ask them: What is the difference between detrital and non-detrital
sedimentary rocks? When talking about detrital sedimentary rocks,
highlight the peculiarities of coal and petroleum as combustible
fossils.
Ask students How do sediments transform into sedimentary
rocks?
Explain the origin of sediments from the erosion of rocks
by geological agents, and the posterior transportation and
sedimentation. The illustration on page 56 will visually help
students to understand this process. Once they understand the
formation of sedimentary rocks, you can carry on explaining the
processes that could happen in the diagenesis: the compaction
and the cementation.
These sedimentary rocks originate from the remains of living
things that have not decomposed. They can burn and produce
energy.
Coal could be from different types according to their calorific value.
From the least to the most calorific, they are classified in peat, lignite,
coal and anthracite. The calorific value depends on the quantity of
coal: more coal, more powerful.
Reading comprehension: THE ROCK OF AGES
Answer key
This text is about how slow the geological processes happen. Students will realise how much implicated are human beings in these
processes since millions of years while the sand transformation in
rock is still happening.
Analyse
21. 2.5 cm of sediments are accumulated every 10 years in
a sedimentary basin. After the process of compaction,
will the volume of sediment be thicker or thinner?
Explain your answer.
3.2.1. Formation of sedimentary rocks
Ask students to read section 3.2.1 and then close their books.
Read out the process for either compaction or cementation and
ask them to stand up if you defined one or the other.
The thickness will be 0.25 cm every 10 years.
22. Explain why water is important in the formation of
sedimentary rocks.
Students could now do questions 21 and 22. For question 21, ask
students to work on this problem in pairs. For question 22, they
should re-read section 3.2.1 first and then answer the question.
Because sediments, before transforming into sedimentary
rocks, must lose water by compaction or cementation.
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Analyse
23. Can you explain why limestone, which contains
remains of living things, cannot be burned like coal or
petroleum?
Because fossil remains in limestone are fossilized and
consequently they lose their organic part and just have left
hard parts like carapaces, shells, etc.
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3.3. Metamorphic rocks
3.4. The rock cycle
Rocks that are located deep in the crust are subjected to the pressure created by
the rocks above them. In addition, if these rocks are near magma, they are also
exposed to high temperatures. Pressure and high temperature causes changes in
the minerals that compose a rock and a new rock forms.
Any rock can be transformed into a different type of rock.
The rock cycle is a series of processes that a rock goes through to transform
into another type of rock.
❚ Metamorphism is the process that changes a rock into a different type of
rock.
These processes occur very slowly, so the rock cycle takes place over millions of
years.
❚ Rocks that form in this way are called metamorphic rocks.
Metamorphic rocks are classified according to their texture, in two groups: foliated
and non-foliated.
❚ In foliated metamorphic rocks the minerals are arranged to form parallel
layers. This layered structure is easily observed in many rocks of this type.
Foliated metamorphic rocks are identified from low to high grades of
metamorphism: slate, schist, gneiss and migmatite.
Slate results from the
metamorphism of clay.
It is composed of small
crystals visible under the
microscope. Slate breaks into
thin sheets.
Schist comes from clay,
after a higher metamorphism
than in the case of slate.
Its crystals are visible without
a microscope.
Gneiss originates from
detrital sedimentary rocks or
from granite. Its crystals are
bigger than those in schist.
They are arranged in wavy
bands.
Migmatite are rocks half
way between igneous and
metamorphic rocks. They have
experienced a very intense
metamorphism that partially
melts the original rock.
The rock cycle
All rocks, exposed to the action of wind and water, can go undergo the processes
of erosion, transportation and sedimentation. Sediments deposited in sedimentary
basins undergo the process of diagenesis or lithification and are transformed into
sedimentary rocks.
❚ In non-foliated metamorphic rocks the minerals are not arranged in layers.
The most common are marble and quartzite.
Marble originates
from the metamorphism
of limestone.
Its minerals are
transformed due
to exposure to high
temperatures.
Quartzite originates from
the metamorphism of
sandstone. Like marble,
it forms due to the exposure
of the original rock to high
temperatures.
The rocks in the Earth’s crust are subjected to high pressures and/or temperatures
form metamorphic rocks. If the rocks melt, magma will form. Magma can rise and
cool under the crust, creating plutonic igneous rocks. Magma can also come out
of the crust to the exterior and solidify, creating volcanic igneous rocks.
Understand
25.
Listen, look at the rock cycle and say true or false.
26. In which layer of the geosphere does the rock cycle take place? Which
rocks form at the deepest level?
Analyse
24. Compare the igneous and metamorphic rock processes. What conditions
are needed for a rock to transform into metamorphic rock and not
igneous when subjected to high temperatures?
Key concepts
❚ Rocks are aggregates of two
or various minerals.
Analyse
27. Explain which types of rocks can transform into igneous rocks.
58
❚ According to their origin, rocks
are classified into igneous or
magmatic, sedimentary, and
metamorphic.
❚ The process by which rocks
transform into different rocks
is called the rock cycle.
3. The geosphere
59
3.3. Metamorphic rocks
3.4. The rock cycle
Metamorphic rocks originate from the transformation of other rocks
because of the increased pressure, high temperature or both. Those
factors act on the rocks that are placed in the interior of the Earth
and provoke a reshaping or a change in the composition of rocks,
changing them into a different type of rock.
Ask students: How can rocks change into something different?
Tell them to read the text, look at the image and discuss the
process involved in rock transformation in pairs. Ask them: Can
a metamorphic rock change directly into an igneous rock? For a
rock to be metamorphic, does it have to be a sedimentary rock
first?
To become a metamorphic rock, the rock cannot melt before its
formation. If the original rock melts, magma will form. Magma
can rise and cool under the crust, creating plutonic igneous rocks.
Magma can also come out of the crust to the exterior and solidify,
creating volcanic igneous rocks.
Ask the students to close their books and then ask them to help
you draw the rock cycle on the board, step by step. Give cues
when necessary. The ask them to copy their own versions in their
notebooks.
When you finish this section, it is important to highlight that rocks
are variable and are constantly changing, either because of external
agents or pressure increase or high temperatures. It causes a slow but
constant transformation on the rocks called the rock cycle.
Students could now do questions 25 to 27. For question 25,
pPlay the audio twice, the second time ask students to raise their
hands if they think the sentence is true. Before doing question 26
they should look at the diagram of the rock cycle once again. For
question 27, ask students to discuss this in small groups and to
come up with three simple explanations.
Students could now do question 24. Before answering, they need
to review the section on igneous rocks in order to complete the task.
The science practical suggested on page 64 will clarify concepts of
this section.
Finish this section reviewing the Key concepts on page 59.
Curricular adaptation: 6. THE ROCK CYCLE
Web page: IDENTIFYING ROCKS
Section adapted according to the curriculum.
Short quiz to finish this section. There are different questions
about a photo. Students could make an identification key from
the questions and answers of the identified rocks.
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Answer key
3
In the Earth’s crust, the most superficial layer, where materials
are solidified, thus forming rocks. At the deepest level, we
find plutonic igneous rocks and metamorphic rocks because
those depend on high pressure and high temperature, very
common in deepest areas.
Analyse
24. Compare the igneous and metamorphic rock
processes. What conditions are needed for a rock to
transform into metamorphic rock and not igneous
when subjected to high temperatures?
Analyse
27. Explain which types of rock can transform into igneous
rocks.
Igneous rocks are formed when magma (melted minerals) rises
to the surface, and as it cools it becomes solid. Metamorphic
rocks are rocks that change into a different type of rock when
exposed to pressure and high temperature.
An igneous rock or magmatic rock can transform into any
types of rocks:
Understand
–
Sedimentary rock: if it is subjected to the following
agents of the external geological processes: weathering,
erosion, transportation, sedimentation or deposit of
those fragments and diagenesis or transformation in a
sedimentary rock.
–
Magmatic rock: if it is subjected to high temperatures
that provoke a fusion and again another transformation
into magma. When magma solidifies, a new igneous
rock is formed.
–
Metamorphic rock: if it is subjected to high pressure/
temperature (metamorphism), without melting it but
transforming it into a different rock.
25. Listen, look at the rock cycle and say true or false.
Audio script and answer:
a) The rock cycle is a series of processes that a rock goes
through. (True)
b) The processes happen very quickly. (False)
c) Not all rocks can undergo the processes. (False)
d) If the rocks melt, magma will form. (True)
26. In which layer of the geosphere does the rock cycle
take place? Which rocks form at the deepest level?
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4. THE USE OF ROCKS
5. EXTRACTION OF MINERALS AND ROCKS
The evolution of humans since the Palaeolithic Age has been linked to the use
of rocks for building, ornamentation or making utensils for hunting. Today, we
continue to use rocks for these activities.
Rocks and minerals are extracted from mineral deposits in the Earth’s crust.
A deposit is the place where minerals or rocks are found in sufficient quantity
to make extraction economically beneficial.
The main uses of rocks are building, ornamentation and as a source of fuels and
technological materials.
The minerals that are of interest to extract are called ore deposit. The other rocks and
minerals are referred to as gangue.
❚ Building materials: some rocks are used directly. Others are modified for
building purposes.
To locate a deposit drill holes are made with large drills. Cylinders of earth are
extracted and then analysed.
Cement, concrete, ceramics and glass are some of most commonly used building
materials. They all come from rocks.
Depending on how deep a deposit is and its accessibility, the extraction can be
superficial or subterranean.
❚ Superficial extractions: rocks and minerals are extracted from the surface or
not very deep under the surface. This type of extraction has a great impact on the
environment. There are various types:
• In opencast mines, such as those in Riotinto (Huelva), the minerals are not
deep underground. To extract them, they make funnel-shaped holes (pits). The
edges are stepped to transport the minerals to the surface.
3
harden: to become hard
Remember
Cement is obtained by grinding and
heating limestone and clay. It is mixed
with water to create a substance that
hardens3 when dry. It allows us to stick
rocks together.
Concrete is created by mixing cement,
water, sand and gravel. When dry, it
is harder and stronger than cement.
This is why it is used for pillars and
foundations.
Ceramics are made with pulverised
clay mixed with water, modelled and
cooked at high temperatures.
They are used to make bricks, tiles
or dishes.
Glass is created from quartz present
in sand. Sand is placed in an oven at a
high temperature and it melts. When
cooled, glass can be shaped in different
ways.
• In quarries, large rocks are extracted, cut into blocks or slabs. An example are
the marble quarries in Macael (Almería).
• Gravel4 is extracted from gravel pits. These are usually found in or near large
riverbeds. There are many in the Tajo river basin.
❚ Subterranean extractions: rocks and minerals are located deep within the crust
and are extracted using underground mines. Vertical tunnels called shafts are
constructed and horizontal tunnels or galleries called adits, to extract the minerals.
28. Make a table of rocks
used to make building
materials. Include what
materials they are used
to make and the uses of
those materials.
29. Which types of rocks
are usually used for
decoration?
Understand
30. Explain the difference
between concrete and
cement.
Key concepts
❚ Rocks are used, directly
or modified, as building
materials.
❚ Rocks also have ornamental
uses, as fossil fuels or as
a source of minerals for
technological use.
4
gravel: a mixture of rock fragments
between 2 and 64 mm
Understand
32. Explain in your own
words, the difference
between a subterranean
mine and a quarry.
❚ Ornamental rocks: marble, granite, slate and basalt are often used in decoration.
Due to their beauty once they have been carved and polished, these rocks are
used in sculptures, floors of buildings and many other decorative elements in the
interior and exterior of buildings.
Key concepts
❚ Source of fossil fuels: sedimentary rocks such as coal and oil are used because
they produce a lot of when burnt.
Extraction of rocks
❚ Source of minerals for technological use: rocks rich in quartz are a source of
silicon, which is used to make computer processors or photovoltaic solar panels.
Aluminium, obtained from a sedimentary rock called bauxite, is used to make
many objects such as planes, soft drink cans or kitchen utensils.
Understand
31. What type of superficial extraction is shown in the picture?
60
❚ A deposit is the place
where minerals or rocks are
extracted.
❚ Extractions are classified
according
to
depth:
superficial or subterranean.
3. The geosphere
61
4. The use of rocks
5. Extraction of minerals and rocks
Ask the students: What objects can you see around you that are
made of rocks? Probably they will find objects related to building.
However, rocks are useful in the majority of objects around us,
from building to technological ones.
This section could make students think about the importance of
sustainable management of mineral and rock resources. It is essential to know the consequences of the uncontrolled use of those resources, both for the environment and for people.
Read the following sentences just to review some types of rocks
that will be useful during the lesson:
It is important that students become aware of the need for searching for alternatives to use and overuse of non-renewable resources as well as their consequences. Sustainable use of mineral
and rock resources allow better work conditions for millions of
people and also avoid unnecessary risks. Now students do questions 31 and 32.
❚ Granite and basalt are igneous or magmatic rocks.
❚ Limestone, clay, coal and petroleum are sedimentary rocks.
❚ Marble and slate are metamorphic rocks.
Tips: 31. Ask students to look at the different definitions of extraction and the image. 32. Elicit different answers from the class.
Human beings have been using rocks since the Palaeolithic
Age. At the beginning their use was natural, such as refuges
(caves or caverns) or utensils for hunting. Nowadays, the
main use of rocks is for building, ornamentation, and as a
source of fuels and technological materials. In the latter, they
do not use rocks directly to produce them, but rather minerals
extracted from them like aluminum, which is obtained from
bauxite.
Web page: THE PROCESS OF GOLD EXTRACTION
AND ITS USE
To finish this section, students could watch this video. It is about
the extraction of gold and its importance to humans. After
watching the video, answer the questions on the worksheet.
Now, students should do questions 28 to 30. 28. Ask students to
do this in their notebooks and then compare with another student. 29. Do this as a whole class activity, eliciting the answer. 30.
Write different possibilities on the board and then ask students to
choose the most appropriate answer for each.
Curricular adaptation: 8. MINERAL AND ROCK
EXTRACTION
Section adapted according to the curriculum.
Review concepts learnt in this section by reading the Key
concepts on page 60.
Curricular adaptation: 7. THE USE OF ROCKS
Section adapted according to the curriculum.
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Answer key
3
Understand
31. What type of superficial extraction is shown in the
picture?
Remember
28. Make a table of rocks used to make building
materials. Include what materials they are used to
make and the uses of those materials.
Rocks
Materials
Uses
Cement
Limestone and clay
Stick rocks
together
Concrete
Cement, water,
sand and gravel
Build pillars and
foundations
Ceramics
Pulverised clay
mixed with water
Make bricks, tiles
or dishes
Glass
Quartz present in
sand
Make windows,
bottles, glasses
29. Which types of rocks are usually used for decoration?
It is an opencast mine, they are making a funnel-shaped hole
(piles) to extract.
Plutonic rocks because of their beauty once they have been
cut and polished.
32. Explain in your own words the difference between a
subterranean mine and a quarry.
Understand
In subterranean mines, vertical tunnels called shafts and
horizontal tunnels or galleries are constructed to extract the
minerals while in quarries, minerals are extracted from the
surface or not very deep under the surface and it has a great
impact on the environment. Large rocks are extracted and
cut into blocks or slabs.
30. Explain the difference between concrete and cement.
Cement is made from grinding and heating limestone and
clay. Concrete is created by mixing cement, water, sand and
gravel. When dry, it is harder and stronger than cement. This
is why it is used for pillars and foundations.
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CONSOLIDATION
The Earth: origin and composition
33. Find out the thicknesses of the different layers of
the Earth and order them from thickest to thinnest.
34. Make a table to compare the characteristics of the
continental crust and the oceanic crust.
39. Describe four properties of minerals.
The use of rocks
40. Explain if an ice cube and coral used in jewellery
are minerals or not.
53. Explain which rocks provide the following building
materials:
41. Investigate and then copy and complete the table
in your notebook.
35. Were all materials distributed according to their
density from the very beginning? Explain your
answer.
36. Explain why the following statements are true or
false.
a) The seismic method only allows us to know the
composition of the Earth’ s crust.
b) The Earth is made up of solid materials.
c) The Earth’ s crust has a uniform thickness of 50 km.
d) Denser materials in the geosphere are found on the
Earth’ s surface.
e) The Earth’ s mantle is located between the Mohorovičić
discontinuity and the Lehmann discontinuity.
f) The Earth’ s inner core is solid because the temperature is
lower than in the outer core.
37. The following graph shows how seismic waves
move around the planet. Which seismic wave is
travelling at a higher speed? Which layers of the
Earth do they go through?
Moho
Gutenberg
Lehmann
Speed of siesmic wave (km/s)
12
Ore
...
...
Lead
Hematite
...
...
Zinc
Chalcopyrite
...
Waves S
6
c) cement
e) brick
b) concrete
d) lime
f) tile
55. What is sandpaper? Explain why it is not made of
fragments of gypsum or talc.
56. Copy and complete the table in your notebook for
the following rocks: petroleum, chalk, limestone,
clay and coal.
42. According to the Mohs scale, what is the hardness
of a mineral that scratches orthoclase but is
scratched by quartz?
43. Explain how can you distinguish white quartz from
orthoclase which is the same colour?
Rock
Use
Objects created with it
...
...
...
Outer
core
Mantle
0
1 000
2 000
3 000
4 000
Inner
core
5 000
6 000
Depth (km)
Minerals
38. Which property of materials
does the image show?
Slow but sure
In Chihuahua, Mexico, giant crystals were found in the
cave of Naica. They are mega-crystals of selenite (a variety
of gypsum). For years, the Spanish investigator Juan
Manuel García has been studying how fast they grow.
Thanks to a special microscope designed by Japanese
engineers, we now know that these formations grow
at the equivalent of one hair every 100 years. However,
their growth has stopped in recent years due to mining
activities, to extract minerals from the underground
water that the minerals need to grow.
57. Research how concrete and bricks are made. Make
a diagram.
44. Find out why the colour and streak of a mineral
isn’t always the same.
45. Find out why pyrite is also referred to as ‘fool’s gold’.
Rocks
46. Explain the three characteristics that are used to
classify rocks.
47. Pumice is a rock that floats in water. Why do you
think this is? Is it a natural or an artificial rock?
Justify your answer.
EVA VAN DEN BERG
National Geographic, November 2011
(Translated and adapted)
Extraction of minerals and rocks
a) What is the text about?
58. Complete the sentences in your notebook.
a) The rocks extracted from ….. are cut into blocks.
b) ….. are horizontal tunnels in underground mines.
c) ….. is sediment that is usually extracted in or near large
riverbeds.
b) Can you explain the title?
59. Explain the meaning of the terms deposit and mine.
c) Why have the crystals stopped growing?
d) Do you think the growth of these formations can be
observed by any person?
e) Find out about selenite. Explain why water is
essential for its formation.
STUDY SKILLS
❚ Create your own summary of the unit using
the Key concepts. Add any other important
information.
49. Are there any rocks which are not composed of
minerals? What type of rocks are they?
3
61. Discuss this statement: ‘New generation mobile
telephones are made of stone’.
READ AND UNDERSTAND SCIENCE
54. Why are coal and petroleum referred to as fossil fuels?
48. Copy the following terms in two columns in your
notebook and then match them.
A: limestone, granite, clay, marble, basalt, chalk, detrital
sedimentary
B: non-detrital sedimentary, plutonic, volcanic, foliated
metamorphic, non-foliated metamorphic
Waves P
9
0
Mineral
Cassiterite
a) glass
60. Find out what a slag heap is. What environmental
problems do they cause?
❚ Copy the following diagram in your
notebook and add the missing information
to create a conceptual map of the unit.
You can record
your
summary and
list
to it as many tim en
es
as you like to
revise.
The geosphere
50. When 1 kg of granite was analysed in the laboratory
using different chemical processes they obtained
250 g of a white mineral, 300 g of another mineral,
almost black, and the rest was a grey mineral.
a) What is the name of each mineral that composes granite?
b) Which mineral corresponds to the grams of minerals
above?
is divided in
51. On an excursion, Ana found a rock that contained
a plant fossil that lived on Earth millions of years
ago. What type of rock do you think it was? Explain
your answer.
is composed of
layers
minerals
rocks
...
are classified by
are classified by
...
...
❚ Create your own scientific glossary. Define the following terms: quarry, clast, sedimentary basin, deposit, discontinuity,
reef, phytoplankton, fossil, gallery, gangue, geosphere, gravel, magma, metamorphism, mineral, ore, rock, sediment,
seismic wave. Add any other terms you consider important.
52. Which rock forms quartzite after metamorphism?
What size are the grains of the original rock?
62
3. The geosphere
The Earth: origin and composition
36. Explain why the following statements are true or
false.
33. Find out the thickness of the different layers of the
Earth and order them from thickest to thinnest.
a) The seismic method only allows us to know the
composition of the Earth’s crust. False, it allows us to
know the composition and the structure of the Earth’s
interior.
Crust: between 6 and 70 km thick
Upper mantle: up to 670 km deep; around 600 km thick
b) The Earth is made up of solid materials. False, it is
made up of solid materials and molten rocks like in the
upper mantle and in the outer core.
Lower mantle: up to 2900 km deep; around 2230 km thick
Outer core: up to 5120 km deep; around 2220 km thick
Inner core: up to 6370 km deep; around 1250 km thick
c) The Earth’s crust has a uniform thickness of 50 km.
False, the thickness is variable in the Earth’s crust, for
example, the continental crust is thicker than the oceanic
crust.
In order from the thickest to the thinnest: lower mantle-outer
core-inner core-upper mantle-crust
34. Make a table to compare the characteristics of the
continental crust and the oceanic crust.
Characteristics
The age of materials
that formed it
Thickness
Rocks that formed it
Superficial reliefs that
composed it
Continental Crust
63
d) Denser materials in the geosphere are found on
the Earth’s surface. False, in the geosphere the densest
materials are found in the inner core and the lightest ones
in the crust.
Ocean Crust
More than 1 000
200 million years old
million years old
Between 10 and 70 km Between 6 and
10 km
Granite, clay and slate
Basaltic rock
Continental platform,
Sea floor
continent and islands
e) The Earth’s mantle is located between the
Mohorovicic discontinuity and the Lehmann
discontinuity. False because the Earth’s mantle is located
between the Mohorovicic discontinuity and the Gutenberg
discontinuity.
f) The Earth’s inner core is solid because the temperature
is lower than in the outer core. False, the inner core is
solid although its temperature is colder than in the outer
core, because the pressure is higher.
35. Were all materials distributed according to their density
from the very beginning? Explain your answer.
No, the density differentiation happened after the process
called accretion of planetesimals.
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The Geosphere
37. The following graph shows how seismic waves move
around the planet. Which seismic wave is traveling at
a higher speed? Which layers of the Earth do they go
through?
Moho
Gutenberg
42. According to the Mohs scale, what is the hardness of
a mineral that scratches orthoclase but is scratched by
quartz?
The hardness will be between 6 to 7 according to the Mohs
scale.
43. Explain how you can distinguish white quartz from
orthoclase which is the same colour.
Lehmann
Speed of siesmic wave (km/s)
12
We can distinguish them by other characteristics or properties,
like the streak or the lustre. The streak in the quartz is always
white. In case there are a fragment of quartz and another one
of orthoclase, you can compare their hardness as the quartz
scratch the orthoclase, but not the other way round.
Waves P
9
Waves S
44. Find out why the color and streak of a mineral isn’t
always the same.
6
3
Outer
core
Mantle
0
3
1 000
0
2 000
3 000
Because the colour of the streak or the powder produced
when a mineral is scratched is actually its ‘original colour’,
according to its chemical composition and its crystalline
structure. The colour of a mineral could have been influenced
by external factors and caused a variation on its original
colour.
Inner
core
4 000
5 000
6 000
45. Find out why pyrite is also referred to as ‘fool’s gold’.
Depth (km)
Because its appearance (colour and lustre) is similar to the
gold, but its commercial value is much cheaper. Historically,
millions of people were fooled by buying pyrite rather than
gold.
P waves are traveling at a higher speed.
P waves go through all layers of the Earth’s interior, while S
waves only go through the crust and the mantle.
Rocks
Minerals
46. Explain the three characteristics that are used to classify
rocks.
38. Which property of materials does
the image show?
The three characteristics that are used to classify rocks are:
Tenacity and resistance, that shows
when a mineral breaks.
- Composition: minerals that make up the rock.
- Texture: size and arrangement of the minerals in the rock.
39. Describe four properties of minerals.
- Origin: the way that the rock was formed.
Open answer. Students could choose four of the several
properties of minerals mentioned in the unit.
47. Pumice is a rock that floats in water. Why do you think
this is? Is it a natural or an artificial rock? Justify your
answer.
40. Explain if an ice cube and coral used in jewelry are
minerals or not.
Because it has many small holes in the surface. These were
formed by gases that were in the rock before solidified.
An ice cube is not a mineral because it is made up by a
human being when freezing water and giving it an artificial
geometrical shape. On the other hand, the natural ice is
considered a mineral.
48. Copy the following terms in two columns in your
notebook and then match them:
Limestone
Detritial Sedimentary
The coral used in jewelry is not a mineral because it is not
inorganic, it is formed by an animal called coral.
Granite
Non-detritial Sedimentary
41. Investigate and then copy and complete the table in
your notebook.
Clay
Plutonic
Marble
Volcanic
Basalt
Foliated metamorphic
Chalk
Non-foliated metamorphic
Ore
Metal
Bauxite
Aluminium
Blend
Zinc
Chalcopyrite
Copper
Cassiterite
Tin
Cinnabar
Mercury
Galenite
Lead
Hematite
Iron
49. Are there any rocks which are not composed of
minerals? What type of rocks are they?
Yes, coal and petroleum. These rocks are classified by looking
at the origin of the sediments that compose them and are
called sedimentary rocks.
50. When 1 kg of granite was analysed in the laboratory
using different chemical processes they obtained 250
g of a white mineral, 300 g of another mineral, almost
black, and the rest was a grey mineral.
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The Geosphere
57. Research how concrete and bricks are made. Make a
diagram.
a) What is the name of each mineral that composes
granite?
Feldspar, quartz and mica.
For example:
b) Which mineral corresponds to the grams of minerals
above?
Heating and milling of
limestone and clay.
Mixed with sand,
gravel and water.
Concrete
Feldspar: 250 g of a total of 1 000 g = 25 %
Milling and
pulverization
of clay.
Quartz: 300 g of a total of 1 000 g = 30 %
Mica: 450 g of a total of 1 000 g = 45 %
51. On an excursion, Ana found a rock that contained a
plant fossil that lived on Earth millions of years ago.
What type of rock do you think it was? Explain your
answer.
Mixed with
water and
model.
Oven at high
temperature:
cooking process.
Bricks
Extraction of minerals and rocks
58. Complete the sentences in your notebook.
a) The rocks extracted from quarries are cut into blocks.
It is a sedimentary rock, it was probably formed on the Earth’s
surface including a plant fossil between the sediments that
originated it.
b) Adits are horizontal tunnels in underground mines.
c) Gravel is a sediment that is usually extracted in or
near large riverbeds.
52. Which rock forms quartzite after metamorphism? What
size are the grains of the original rock?
59. Explain the meaning of the terms deposit and mine.
The sandstone, with a size above 2 mm.
A deposit is the place where minerals are found in sufficient
quantity to make extraction economically beneficial while a
mine is the place that is more profitable to explore by human
beings.
The use of rocks
53. Explain which rocks provide the following building
materials.
60. Find out what a waste dump is and what environmental
problems it presents.
a) Glass: sandstone
b) Concrete: mixed cement, water, sand and gravel (little
fragments of sedimentary rocks).
A waste dump is a place on the Earth’s surface where
human beings throw rests of building materials such as
bricks, cement, concrete, etc. Those places cause lots of
environmental problems. Living things that used to live in
those places will be moved or destroyed by those rests.
c) Cement: limestone and clay
d) Lime: limestone
e) Brick: clay
f) Tiles: clay; although there are areas where tiles are made
up by slates and similar materials.
61. Discuss this statement: ‘New generation mobile
telephones are made of stone.’
54. Why are coal and petroleum referred to as fossil fuels?
The statement means that a lot of materials that are used to make
new generation mobile phones are extracted from the rocks.
They are combustible because they produce energy for the
human beings. And they are fossils because they originate
from the remains of living things.
READ AND UNDERSTAND SCIENCE
a) What is the text about?
55. What is sandpaper? Explain why it is not made of
fragments of gypsum or talc.
It is about some giant crystals that were found in the cave of
Naica, Mexico.
It is an utensil used in building and DIY made up of a paper
or cardboard in which there are fragments of hard sand stuck
on it. It is used to smooth surfaces and it cannot be made up
of gypsum or talc, because these have a low hardness.
b) Can you explain the title?
The title refers to the velocity to form those crystals.
c) Why have the crystals stopped growing?
Due to mining activities to extract minerals.
56. Copy and complete the table in your notebook for the
following rocks: petroleum, chalk, limestone, clay and
coal.
OBJECTS CREATED WITH IT
No, because these formations grow at the equivalent of one
hair every 100 years.
Combustible
and raw
material
Petrol or diesel and plastics such
as bottles
e) Find out about selenite. Explain why water is essential
for its formation.
Building
Cement
ROCK
USE
PETROLEUM
LIMESTONE
d) Do you think the growth of these formation can be
observed by any person?
CHALK
Building
Roofs, walls, coating, etc.
CLAY
Building
Bricks
COAL
Combustible
Energy source
Selenite is a variety of gypsum made up of hydrated calcium
sulphate, and it needs water during its process to hydrate.
STUDY SKILLS
Open answer
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The Geosphere
3
EXTENSION ACTIVITIES
Web page: THE EARTH’S CRUST AND ITS MATERIALS
Various revision activities.
Above the Earth’s crust, there are a group of inert materials such
as minerals and rocks. This web page will help students to review
the main contents of this unit and to do the activities.
Curricular adaptation: ASSESSMENT
Adapted for mixed abilities.
CONCEPTUAL MAP
To introduce the contents of the unit, you could show to the
student an incomplete conceptual map and ask them to complete
the gaps in their notebook or orally with the whole group. This
will help students to globally visualise the links between the
different contents of the unit.
ASSESSMENT TEST
Assess the learning outcomes that are seen in the unit.
PRESENTATION
Use the slideshow presentation to show the different sections
in the unit and to evaluate student’s learning. This tool can also
be used as revision at the end. The slides can stimulate student
participation, as they can be asked about certain topics before
they study them.
REVISION ACTIVITIES
Various revision activities.
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WORK AND EXPERIMENTATION TECHNIQUES
The Geosphere
3
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WORK AND EXPERIMENTATION TECHNIQUES
The texture of rocks
Some characteristics of rocks cannot be seen just by looking at
them. In this practical, you will learn to use a binocular loupe
to compare different rocks and distinguish them according to
texture.
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www
FINAL TASK
www
The environmental impact of mineral extraction
The objective of this task is to research
the environmental and social impact of
extracting coltan. You will present your
information in a slideshow presentation
and suggest some measures to contribute to solving the
problems.
Materials
❚ Binocular loupe
❚ Five different rocks, for example,
conglomerate, sandstone, basalt,
granite and gneiss
❚ Ruler
1. Research
Procedure
a) What are the negative effects of mineral extraction on the environment?
2. Tasks
1. Put each rock, one by one, on the slide of the binocular loupe. Look through the eyepieces
and move the macrometric screw until the rock is sharply focused.
b) What is coltan and what it is used for?
c) Where are the main coltan mines located? Are there any in Spain?
a) Prepare a slideshow presentation.
2. Observe each rock, and draw what you see for each rock.
d) How does the behaviour of the consumer affect the exploitation of
children in coltan mines? What can we do to help solve this problem?
b) Make a list of three ways in which we can contribute to the
sustainable management of mineral resources.
3. Place a ruler next to the rock and, with the help of the loupe, measure the crystals
or fragments that compose the rock.
Procedure
4. Do another drawing of each rock observed.
Follow these steps for your research:
Analysis of results
Research
❚ Find at least four different ways in which mines impact the environment and people. Suggest some possible solutions
to the problems.
To analyse the results and compare the rocks, use the following table next to your drawings:
Name of rock
Minerals it is
composed of
Size of the
components
Type of rock
...
...
...
...
❚ Do not trust only one source of information. Check that the answers to your questions are repeated in different
sources.
❚ Make a bibliography of all sources consulted.
Organise the information
❚ Make a table with the main impacts of coltan mining.
❚ Write the answers to the questions in the Research section.
Obtain conclusions and confirm research
❚ As a result of your work, resolve the initial questions of the Final task.
❚ Verify your answers.
❚ Check that you have answered all the questions.
Texture of conglomerate
Texture of gneiss
1.
Which of the observed rocks is homogeneous? How did you know?
2.
What are the main differences between conglomerates and sandstone?
Texture of sandstone
3.
What type of igneous rocks are granite and basalt? Can you observe any differences in their textures?
4.
Based on the results of this practical, define in your own words the different types of rocks (igneous, sedimentary
and metamorphic).
5.
Which of the rocks observed in this practical were formed in the exterior of the Earth’s crust? And in the interior?
SELF-ASSESSMENT
❚ Answer these questions to evaluate your work.
1. Have you resolved all the questions in the Research section?
2. Have you used reliable sources to find information?
3. Have you checked that the answers were repeated in various sources?
4. What rating, from 1 to 5, would you give your presentation?
64
3. The geosphere
The texture of rocks
2.
This science practical complements the contents worked in section
3. In that section the learning standard that is worked on is 7.1.
Identify rocks using information that could differentiate them.
What are the main differences between conglomerates
and sandstone?
Mainly the size of the grain, bigger in conglomerates.
In addition, it will help students to become familiar with materials
and instruments used in a laboratory such as the binocular loupe.
3.
What type of igneous rocks are granite and basalt?
Can you observe any differences in their textures?
Granite is a plutonic rock while basalt is volcanic. The
difference is visible on the texture and we can see the crystals
on a naked eye in the granite.
4.
Based on the results of this practical, define in your
own words the different types of rocks (igneous,
sedimentary and metamorphic).
Student’s own answer
5.
Which of the rocks observed in this practical were
formed in the exterior of the Earth’s crust? And in the
interior?
Conglomerate, sandstone, basalt and gneiss were formed in
the exterior of the Earth’s crust while granite was formed in
the interior as being a plutonic rock.
By doing this laboratory practical students will achieve the
following key competences:
❚ Mathematical competence and basic competences in
science and technology (MCST).
❚ Learning to learn (LL).
❚ Sense of initiative and entrepreneurship (SIE).
Answer key
1.
65
Which of the observed rocks is homogeneous? How
did you know?
Both sandstone and gneiss are homogeneous rocks. It is
checked by observing them with a binocular loupe.
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FINAL TASK
The Geosphere
3
The environmental impact of mineral extraction
The final task of this unit aims to raise awareness of the importance of the sustainable management of mineral resources. Nowadays, we
live in a world of consumers, and we rarely ask ourselves where things we use come from, or the human costs and environmental needs.
When new objects come out in the market, we do not appreciate the ones we have and often refuse to use them even if they still work
properly. We do not even think about what to do with the objects we do not want anymore and how they can pollute the environment if
we do not throw them away properly.
At the beginning of the unit, the final task and its objectives, in this case, were introduced with a slideshow presentation.
On page 47 we introduce the final task with some questions to motivate the curiosity of students.
On page 65 we explain how to do the research and how to prepare the slides.
❚ In the section Research there are four questions to guide students during the research.
❚ In the section Tasks there is a reminder about what they need to do.
❚ The Procedure section indicates the steps students must follow during the research, how they organise the information before making
the slides, and the importance of reviewing all the information to make sure they are doing things correctly.
❚ The Self-assessment at the end of the page will make them think about their work and the development of the final task.
Unfortunately, there is no time to present all the slideshows. Choose one, or reduce the timing presentation and give the chance to another
group.
The learning outcome that will be reinforced by doing this task, in the section 2, is the 10.1. Recognise the importance of minerals and
rocks for humans and of managing these resources in a sustainable way.
The learning outcomes from sections 1 and 7 will be also developed.
An example of how to assess the final task is shown here:
0 = not handed in
1 = very basic
2 = well done
3 = excellent
0
1
2
3
SLIDESHOW PRESENTATION
The presentation is adjusted according to the instructions.
Slides are eye-catching and the proportion of the texts and images is balanced.
Slides include information and images that complement the explanation.
The language, in the oral presentation, was expressed in appropriate and understandable terms.
Images sources consulted were mentioned.
Able to answer the questions proposed by the teacher and classmates.
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15, 16, 48
17, 18, 31, 54
22, 23, 27, 28, 32, 33, 55,56,
58, Work and laboratory
practical techniques
19, 20, 21, 24, 25, 26, 29, 30,
53, 57, 59
6.1 Describe some of the more
frequent uses of minerals in our
daily life.
7.1 Understand the concept
of rock.
7.2 Recognise the three types
of rocks according to their
origin and identify the main
characteristics of each one.
8.1 identify rocks using
information that could
differentiate them.
4, 5, 9
4.1 Understand the concept of
minerals.
11,12, 13, 14, 45, 46, 49, 50,
51, 52
40, 41
3.2 Describe the main
characteristics of the crust, the
mantle and the core and the
materials that have form them.
5.1 Identify minerals using
information that could
differentiate them.
2, 40, 41, 42, 43
3.1 Describe the main
characteristics of the most
frequent materials in the
external areas of the planet
and explain their distribution
according to the density.
6, 7, 8, 10, 47
3, 44
2.1 Relate the layers of the
geosphere and its formation
process.
4.2 Apply the concept of
mineral to recognise if a
substance is or not a mineral.
1, 42
Assessment tools
1.1 Describe the formation
process of the Earth
Evaluable learning
outcomes
Solves all the activities
correctly.
Solves all the activities
correctly.
Explains the concept in a clear
manner, providing quite a few
valid examples.
Explain the concepts in an
appropriate way, providing
quite a few valid examples.
Solves most of the activities
correctly, with mistakes in some
of them.
Solves most of the activities
correctly, with mistakes in some
of them.
Explains the concept in an
incomplete way, providing a
few valid examples.
Explains the concepts in a valid
but incomplete way, providing
a few valid examples.
Solves most of the activities
correctly, with mistakes in some
of them.
Solves most of the activities
correctly, with mistakes in some
of them.
Explains the concept in an
incomplete way, providing
quite a few valid examples.
Explains the concepts in a valid
but incomplete way, identifying
quite a few of the main
elements and its relations.
Explains the concepts in a valid
but incomplete way, identifying
quite a few of the main
elements and its relations.
Explains the process in a valid
but incomplete way, identifying
quite a few of the main
elements.
Explains the process in a valid
but incomplete way, identifying
quite a few of the main
elements.
Satisfactory
2
Solves the activities but makes
mistakes in quite a few of
them.
Solves the activities but makes
mistakes in quite a few of
them.
Explains the concept with
mistakes, providing limited or
non-existent examples.
Explains the concepts with
mistakes, providing limited or
non-existent examples.
Solves the activities but makes
mistakes in quite a few of
them.
Solves the activities but makes
mistakes in quite a few of
them.
Explains the concepts with
mistakes, providing limited or
non-existent examples.
Explains the concepts with
mistakes, identifying few of the
main elements and its relations.
Explains the concepts with
mistakes, identifying few of the
main elements and its relations.
Explains the process with
mistakes, identifying few of the
main elements.
Explains the process with
mistakes, identifying few of the
main elements.
In process
1
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Not achieved
0
Score
The Geosphere
Solves all the activities
correctly.
Solves all the activities
correctly.
Explain the concepts in an
appropriate way, providing
quite a few valid examples.
Explain the concepts in an
appropriate way, identifying
all the main elements and its
relations.
Explain the concepts in an
appropriate way, identifying
all the main elements and its
relations.
Explains the process in a clear
manner, identifying all the main
elements.
Explains the process in a clear
manner, identifying all the main
elements.
Excellent
3
3
LEARNING OUTCOMES RUBRIC
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34, 35, 36, 60, 61, 62, 63, 64
37, 38, 39, 65, 66, 67, 68,
Research task
10.1 Recognise the importance
of minerals and of managing
these resources in a sustainable
way.
Assessment tools
9.1 Describe some of the most
frequent use of rocks in our
daily life.
Evaluable learning
outcomes
GEOLOGY_1ESO_Ud03_LP.indd 127
Explain the concepts in an
appropriate way, providing
quite a few valid examples.
Explain the concepts in an
appropriate way, providing
quite a few valid examples.
Excellent
3
Explains the concepts in a valid
but incomplete way, providing
a few valid examples.
Explains the concepts in a valid
but incomplete way, providing
a few valid examples.
Satisfactory
2
Explains the concepts with
mistakes, providing limited or
non-existent examples.
Explains the concepts with
mistakes, providing limited or
non-existent examples.
In process
1
Answers in an incorrect way or
does not answer.
Answers in an incorrect way or
does not answer.
Not achieved
0
Score
LEARNING OUTCOMES RUBRIC
The Geosphere
3
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OXFORD INVESTIGATION
The Geosphere
Objectives, contents and methodology
TYPES OF RESOURCES AND METHODOLOGY USED TO MEET OBJECTIVES
●
Interactive activities. Elaboration and verification of a hypothesis.
❍
Search for information on the Internet.

Watch videos.
❏
Analyse images.
■
Analyse texts (news articles, scientific articles, etc).
SECTIONS
Minerals
OBJETIVES AND CONTENTS
METHODOLOGY
Identify that aligned atomic structures is a property in minerals (crystalline structure).
●
Recognise the two basic characteristics that define a mineral: chemical and structural
composition.
●
Identify mineraloides as solid bodies without a crystalline structure.
●
Recognise the influence that a crystalline structure has on the properties of minerals.
(Diamond/Graphite).
●
Concepts: mineral, mineraloide, crystalline structure
Rocks
Find out the composition of rocks. Define the concept of rock.
●
Recognise the two basic characteristics that define a rock: mineralogical composition and
texture.
●
Recognise the influence that texture has on the characteristics of rocks (marble,
limestone).
●
Concepts: rocks, mineralogical composition, texture
Rocks
Find out the main types of rocks.
❍

Find out the different processes that form rocks.
❍

Recognise the characteristics of rocks for each type (magmatic, metamorphic,
sedimentary).
❍
❏
Concepts: classification of rocks, magmatic rocks, metamorphic rocks, sedimentary rocks
Extraction of minerals
and rocks
Find out and identify the main types of mineral extractions
❍
Concepts: mineral extractions, superficial extractions, subterranean extractions, gravel pits, quarry
Final task
Recognise minerals, rocks and types of deposits
❍
Analyse the social and environmental impact that could cause the mineral extraction.
■
❏
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EXAM A
The Geosphere
3
6. Correct the following statements.
1. Write the difference between the following concepts:
a) The conglomerate in a non-detrital sedimentary rock
with a superior grain size up to 2 mm.
a) Ore and gangue:
Ore refers to the minerals which are profitable to extract
from a deposit while gangue refers to the ones that are not
profitable to extract.
The conglomerate is a detrital sedimentary rock.
b) Sandstone is a detrital sedimentary rock that produces
effervescence in contact with acids.
b) Colour of a mineral and streak of a mineral:
The colour is the appearance of the mineral while the streak is
the color of the powder produced when a mineral is scratched.
Sandstone does not produce effervescence.
c) Tenacity and cleavage:
Coal and petroleum are formed by organic remains that have
not decomposed.
c) All of sedimentary rocks are formed by minerals.
Tenacity describes how easily a mineral breaks and cleavage
describes the way a mineral breaks.
d) Clay is made up of grains of a size inferior to 2 mm
but easily visible.
2. Make a complete classification of rocks according to
their origin.
The grains of clay only can be observed with a magnifying
glass or a microscope.
3. Why do the seismic methods help us to study the Earth’s
interior?
7. Indicate the name of the processes mentioned:
Because the speed of the seismic waves vary as they pass
from one layer to another. The study of the data obtained
helped scientists to deduce the composition of the Earth’s
interior and thanks to it we know that the Earth is divided
into three layers: the crust, mantle and core.
a) Transforms a magma into igneous rock.
Cooling and solidification.
b) Transforms a sedimentary rock into metamorphic.
Metamorphism.
4. The following diagram shows the layers of the
geosphere. Write the name of each one of them and
their discontinuities.
c) Transforms and igneous rock into sediments.
Weathering, transportation and sedimentation.
d) Transforms a metamorphic rock into magma.
Fusion.
8. What rocks are used as combustible fossils?
Coal and petroleum.
9. Give an example for each case:
a) Soft: calcite, fluorite or apatite
b) Very soft: talc or gypsum
c) Hard: orthoclase or quartz
d) Very hard: topaz, corundum or diamond
10. Look at the images below and explain the types of the
superficial extractions.
5. Explain what happens in the process of diagenesis or
lithification.
It is the process in which sediments transform into sedimentary
rocks.
The image on the left is a quarry. In quarries, large rocks are
extracted and cut into blocks or slabs.
Sediments deposited in sedimentary basins firstly suffer a
process of compaction, when they lose volume due to the
weight of them on top so they become compacted. After
that, cementation takes place after the water is lost and the
salts form crystals. The crystals act like cement and stick the
sediments together to form sedimentary rocks.
The image on the right is an opencast mine. The minerals
are not deep underground so to extract them, they make
funnel-shaped holes (pits). The edge are stepped to
transport the minerals to the surface.
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EXAM B
The Geosphere
1. Indicate the similarities and differences between
opencast mines and underground mines.
c) Plutonic igneous rocks are also called extrusive rocks.
They are both mines to extract minerals. In opencast mines,
minerals are extracted from the surface or hot very deep
under the surface while in underground mines they make
funnel-shaped holes called pits to extract the minerals.
d) Granite is the most abundant volcanic rock in the
continental crust.
Plutonic igneous rocks are also called intrusive rocks.
Granite is a plutonic rock.
6. Answer the following questions:
2. Match the following minerals to their hardness:
Very hard
Hard
Diamond
a) What is the effervescence of a mineral?
Gypsum
It is the capacity to produce bubbles in contact with acids.
Topaz
b) What does it mean if a mineral has a crystalline
structure?
Apatite
Soft
It means that the particles are arranged to form a geometric
structure that is repeated constantly.
Talc
Quartz
Very soft
7. Indicate the ore that correspond to each mineral.
Orthoclase
a) Bauxite: aluminium
Calcite
b) Chalcopyrite: tin
3. Observe the following drawing and explain how the
Earth was formed.
c) Galena: lead
d) Hematite: iron
8. What are decorative rocks and what are they used for?
Give some examples.
Decorative rocks are the ones that after cut and polished
are so beautiful that they could be used to make sculptures,
building floors or any other element of decoration. Marble,
granite and basalt are great examples of decorative rocks.
9. Explain the rock cycle.
The rock cycle is a series of processes that a rock goes through
to transform into another type of rock. These processes occur
very slowly, so the rock cycle takes place over millions of
years. All rocks, exposed to the action of wind and water,
can undergo the processes of erosion, transportation and
sedimentation. Sediments deposited in sedimentary basins
undergo the process of diagenesis or lithification and are
transformed into sedimentary rocks.
4 600 billions of years ago the Sun was formed from chemical
reactions in a giant cloud of dust and gas called nebula. In the
cloud of matter that surrounded the Sun, smaller dust particles
collided and grew in size. This process which formed the
planets is called accretion of planetesimals.
The rocks in the Earth’s crust are subjected to high pressures
and/or temperatures from metamorphic rocks. If the mineral
melts, magma will form. Magma can rise and cool under the
crust, creating plutonic igneous rocks. Magma can also come
out of the crust to the exterior and solidify, creating volcanic
igneous rocks.
For 1 000 million years the Earth was incredible hot. Due to the
immense heat stored in the Earth’s interior, there was a lot of
volcanic activity during the period. As the Earth’s temperature
decreased, gravity pushed heavier elements, such as iron,
towards the Earth’s interior. Lighter elements, such as oxygen,
moved towards the Earth’s surface. This process is called density
differentiation.
10. Look at the following
diagram and explain
the formation of
sedimentary rocks.
4. Draw an explanatory diagram of the parallel layers of
minerals in foliated metamorphic rocks. Why does this
reorientation happen?
The process in which
sediments transform into
sedimentary rocks is called
diagenesis or lithification.
Sediments deposited in
sedimentary basins (1)
often follow two essential
processes for the formation of sedimentary rocks:
It happens because of the pressure on the rocks.
5. Correct the following statements.
Compaction (2) is when sediments lose volume. Due to the
weight of the sediments on top, water is lost and the sediments
become compacted.
a) Volcanic rocks cool slower than plutonic rocks.
Plutonic rocks cool slower than volcanic rocks.
b) Basalt is the most abundant volcanic rock in the
continental crust.
Granite is the most abundant volcanic rock in the continental crust.
Cementation (3) takes place after the water is lost and the
salts form crystals. The crystals act like cement and stick the
sediments together to form sedimentary rocks.
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