Unit 5-The Rocks
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Transcript of Unit 5-The Rocks
7/21/2019 Unit 5-The Rocks
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CIENCIAS NATURALES 1ºESO TEMA 5IES DELGADO HERNANDEZ DEPARTAMENTO DE FÍSICA Y QUÍMICA
UNIT 5: The rocks
VOCABULARY
Here is the vocabulary we are going to use in this unit. You have to look up the
meaning of the missing words and write it down in this table.
WORD MEANING
A rock is made of..... Una roca está hecha de (formada por).......
Absorb Absorber
According to Seg ún
Arrange Arreglar; organizar
Basalt
Bottom Fondo
Build up Acumular
Calcite
Cementation Cementación
Clay
Claystone
Compaction Compactación
Conglomerate
Cycle Ciclo
Derive from Provenir, obtenerse de
Detrital Detrítico
Erupt Entrar en erupción
Extrusive
Fit Ajustar, encajar
Forever Para siempre
Formation Formación
Fossil
Gap Espacio, hueco
Glue Pegamento
Grain
Granite
Gravel Grava
Igneous
Inside (n)interior;(prep)dentro de;(adv)dentro;(adj)interior
Instead En vez de
Interlocking Entrelazado
Intrusive
Lake Lago
Layer
Limestone CalizaLoad Carga
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CIENCIAS NATURALES 1ºESO TEMA 5IES DELGADO HERNANDEZ DEPARTAMENTO DE FÍSICA Y QUÍMICA
Marble
Metamorphic
Molten Fundido, líquido
Porous Poroso
Pressure (n)Presión;(v)presionar
Reach Alcanzar
Recycle Reciclar
Remove Quitar, sacar
Rock
Rounded Redondeado
Sand
Sandstone
Sea Mar
Sediment /
Sedimentary /
Sedimentation
Settle Asentarse
Slate
Split Dividir, separar
Soft / softer Blando / más blando
Squash Aplastar
Stick Pegar
Suffer Sufrir
The oldest El más viejo
The youngest El más joven
Trap (n)Trampa;cazar, atrapar
Underground Subterraneo, bajo tierra
Volcano
Weathering
Weight Peso
THEORY
1) What are rocks?
A rock is made of grains that fit together. Each grain in the rock is made from a
mineral, which is a chemical compound. The grains in a rock can be different
colours, shapes and sizes.
Some types of rock have interlocking grains. Granite is a rock with interlocking
grains. Other types of rock have rounded grains. Sandstone is a rock with
rounded grains.
Rocks with rounded grains absorb more water than rocks with interlocking grains.
This is because the water can get into the gaps between the grains. We call rocks
that absorb water porous. Rocks with rounded grains are usually softer than rocks
with interlocking grains.
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CIENCIAS NATURALES 1ºESO TEMA 5IES DELGADO HERNANDEZ DEPARTAMENTO DE FÍSICA Y QUÍMICA
2) Sedimentary rocks
A. Detrital
Detrital sedimentary rocks derive from the weathering of pre-existing rocks.
Formation
When a river reaches a lake or the sea, its load of transported rocks settles to the
bottom. The deposited rocks build up in layers, that we call sediments. We call
this process sedimentation.The weight of the sediments on top squashes the sediments at the bottom. We call
this compaction.
The crystals form a glue that sticks the pieces of rock together. We call this process
cementation.
It may take millions of years for sedimentary rocks to form. These are the different
processes in order:
sedimentation --> compaction --> cementation
We classify detrital sedimentary rocks according to their texture (grain size)
Gravel: Grain size greater than 2 mm --> conglomerateSand: Grain size 0.02 to 2 mm --> sandstone
Clay: Grain size less than 0.02 mm --> claystone
CONGLOMERATE CLAYSTONE SANDSTONE
B. Chemical/biochemical Sedimentary Rocks
These rocks derive from chemical components dissolved in the seawater. These
chemicals may be removed from seawater and made into rocks by chemical
processes. Examples of these rocks are rock salt and calcite (limestone).
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CIENCIAS NATURALES 1ºESO TEMA 5IES DELGADO HERNANDEZ DEPARTAMENTO DE FÍSICA Y QUÍMICA
CALCITE ROCK SALT
C. Organic Sedimentary Rocks (Coals)
This group consists of rocks composed of organic matter (mainly plant fragments).
These are the coals.
3) Igneous rocks
Formation
The inside of the Earth is very hot - hot enough to melt rocks. Molten (liquid) rock
forms when rocks melt. We call the molten rock magma. When the magma cools
and solidifies, forms igneous rock.
What are they like?
Igneous rocks contain interlocking crystals. The size of the crystals depends
on how quickly the molten magma solidified. If the magma cools quickly,
small crystals form in the rock. This happens when the magma erupts from
a volcano. Basalt is an example of this type of rock. It is an extrusive
igneous rock. If the magma cools slowly, large crystals form in the rock. This
happens if the magma cools deep underground. Granite is an example of
this type of rock. It is an intrusive igneous rock.
BASALT GRANITE
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CIENCIAS NATURALES 1ºESO TEMA 5IES DELGADO HERNANDEZ DEPARTAMENTO DE FÍSICA Y QUÍMICA
Unlike sedimentary rocks, igneous rocks do not contain any fossils.
4) Metamorphic rocks
Metamorphic rocks derive from other rocks that change because of heat orpressure.
Formation
Some rocks suffer heat and great pressures and the minerals that they contain
change: we have a metamorphic rock.
Remember that the rocks that form metamorphic rocks do not melt. Those rocks
that do melt, form igneous rocks instead.
What are metamorphic rocks like?
Crystals in metamorphic rocks arrange in layers.
Slate is useful for making roof tiles because its layers can be split into separate
flat sheets.
Marble is another example of a metamorphic rock. It derives from limestone.
Metamorphic rocks sometimes contain fossils.
SLATE MARBLE
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CIENCIAS NATURALES 1ºESO TEMA 5IES DELGADO HERNANDEZ DEPARTAMENTO DE FÍSICA Y QUÍMICA
5)The rock cycle
Remember that there are three main types of rock:
• Sedimentary, for example limestone, sandstone and conglomerate;
• Igneous, for example basalt and granite;
• Metamorphic, for example slate and marble
The Earth's rocks do not stay the same forever. They are continually changing
because of processes such as weathering and large earth movements. The rocks
recycle over millions of years. We call this process: the rock cycle.
ACTIVITIES
1) Identify the following rocks:
CARACTERISTIC ROCK
Its layers can be split into separate flat sheets.
They derive from chemical components dissolved in theseawater.
The grain size is between 0.02mm and 2 mm
The magma cools slowly, large crystals form in the rock.
The grain size is smaller than 0.02 mm
It derives from limestone.
The magma cools quickly and small crystals form in the rock.
The grain size is greater than 2 mm
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CIENCIAS NATURALES 1ºESO TEMA 5IES DELGADO HERNANDEZ DEPARTAMENTO DE FÍSICA Y QUÍMICA
2) Work in pairs and complete the following sentences with the
right word (or words):
a) A rock is made of __________ that fit togetherb) The Earth's __________ do not stay the same forever
c) __________ is another example of a metamorphic rock
d) Crystals in metamorphic rocks arrange in __________
e) Rocks with __________ absorb more water than rocks with __________.
f) The weight of the sediments on top __________ the sediments at the
bottom.
g) We call the molten rock __________.
h) We call rocks that absorb water __________.
i) Unlike sedimentary rocks, igneous rocks do not contain any __________.
j) Detrital sedimentary rocks derive from the __________ of pre-existing
rocks.
k) The size of the crystals depends on how __________ the molten magma
solidified.
l) It may take __________ for sedimentary rocks to form.
3) The rocks riddle. You have to choose one rock and write two
characteristics of your rock. Your classmate have to guess the
name of the rock. For example:
ROCK CHARACTERISTIC
Marble - It's a metamorphic rock - It derives from limestone.
SOURCES:
- Sparkleboks: http://www.sparklebox2.co.uk/
- Sedimentary Rocks, by Pamela J. W. Gore, Georgia Perimeter College:
http://facstaff.gpc.edu/~pgore/geology/geo101/sedrx.htm#Terrig
- BBC KSbitesi!e:
http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/rock_cycle_9.
shtml
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