Download WORKSHEET 2nd SS LESSON FOUR

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Avda. Juan Pereda Pila, 14 CP 06010 - Badajoz - Tfno. 924 230 280 - Fax: 924 20 71 23
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NATURAL SCIENCES
2ND COURSE (SECONDARY SCHOOL)
WORKSHEET: TYPES OF ROCKS
KEY WORDS:
1ST COURSE
Mining: process of extracting minerals from the Earth.
Nickel: shiny metallic element.
Relief: surface shape, due to differences in height among natural structures on land.
Rust: iron oxide, a reddish-brown compound formed when iron is exposed to air and
moisture.
Seam: underground layer of a mineral or element.
2ND COURSE
Cement: substance like glue that bond particles together to make rocks.
Crystallise: form crystals.
Erosion (to erode): when water, rain and ice remove the surfaces of rocks.
Fuse: mix or join together.
Grain: very small hard piece of something, such as a particle of sand that you can see.
Granular: composed of grains or tiny pieces.
Pore: open space in a rock.
Rough: uneven, irregular.
Sedimentary basin: area where sediments have accumulated.
Sediments: eroded particles of rock that are deposited by water, ice or wind.
Silicate: any compound that contains silicon, oxygen and either one or more metals.
Sink: move down.
Smooth: even, regular.
Solidify: turn into a solid.
CORE CONCEPTS:
1ST COURSE
The Earth is made up of four distinct layers:
THE INNER CORE is in the centre and is the hottest part of the Earth. It is solid and
made up of iron and nickel.
THE OUTER CORE is the layer surrounding the inner core. It is a liquid layer, also made
up of iron and nickel.
Provincia Marista Mediterránea |COLEGIO MARISTA NTRA. SRA. DEL CARMEN| Badajoz
Avda. Juan Pereda Pila, 14 CP 06010 - Badajoz - Tfno. 924 230 280 - Fax: 924 20 71 23
www.maristasbadajoz.com | [email protected]
THE MANTLE has a thickness of approximately 2,900 km. The mantle is made up of
semi-molten rock called magma. In the upper parts of the mantle the rock is hard, but
lower down the rock is soft and beginning to melt.
THE CRUST is a thin layer between 0-60 km thick. The crust is the solid rock layer upon
which we live.
The Earth crust is made up of ROCKS which in turn are made up of MINERALS
and CRYSTALS.
Minerals (studied by MINERALOGY) and crystals (studied by CRYSTALLOGRAPHY)
have the following features:
•
They are SOLIDS.
•
They occur NATURALLY.
•
They are INORGANIC.
•
They have DEFINITE CHEMICAL COMPOSITIONS.
•
Their atoms have a SPECIFIC, ORDERED PATTERN.
If any of them have not a specific, ordered pattern is called MINERALOID.
Mineralogists group minerals into families based on their chemical composition:
NATIVE ELEMENTS:
This is the category of the pure. Most minerals are made up of combinations of chemical
elements. In this group a single element like the copper shown here are found in a
naturally pure form. E.g: Gold, silver and copper.
OXIDES:
Oxides form from the combination of a metal with oxygen. E.g: Haematite and magnetite.
SULFIDES:
Sulfides are made of compounds of sulfur usually with a metal. They tend to be heavy
and brittle. E.g: Pyrite, galena and cinnabar.
SULFATES:
are made of compounds of sulfur combined with metals and oxygen. It is a large group
of minerals that tend to be soft, and translucent. E.g: Gypsum and barite.
HALIDES:
form from halogen elements like chlorine, bromine, fluorine, and iodine combined with
metallic elements. They are very soft and easily dissolved in water. E.g: Halite and
fluorite.
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Avda. Juan Pereda Pila, 14 CP 06010 - Badajoz - Tfno. 924 230 280 - Fax: 924 20 71 23
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CARBONATES:
are a group of minerals made of carbon, oxygen, and a metallic element. E.g: Calcite,
aragonite, malachite and azurite.
PHOSPHATES:
are not as common in occurrence as the other families of minerals. They are often
formed when other minerals are broken down by weathering. They are often brightly
colored. E.g: Apatite and turquoise.
The properties of minerals help us to identify them. The most important ones are:
1. COLOUR: some minerals can be easily identified as they are always the same
colour.
2. LUSTRE: how light is reflected from the Surface of a mineral. It can be metallic or
non-metallic. Non-metallic lustre can be vitreous (the mineral looks like broken
glass), pearly (the mineral changes colour according to the light, like pearls do) or
greasy (the mineral looks like oil on water). If the mineral has no lustre we say it is
dull.
3. STREAK: the colour of the mineral in powder form.
4. CLEAVAGE: the ability of a mineral to break along planes of weakness: this
produces regular fragments. Mica breaks into thin sheets, so it has basal
cleavage. Pyrite breaks into cubes, so it has cubic cleavage.
5. HARDNESS: resistance to scratching. To find out the hardness of a mineral, we
use the Mohs scale.
Provincia Marista Mediterránea |COLEGIO MARISTA NTRA. SRA. DEL CARMEN| Badajoz
Avda. Juan Pereda Pila, 14 CP 06010 - Badajoz - Tfno. 924 230 280 - Fax: 924 20 71 23
www.maristasbadajoz.com | [email protected]
2ND COURSE
Rocks found on the Earth's surface actually come from inside the Earth - so they
tell us a lot about the Earth's interior.
They are classified (organised) into three main groups:
1. IGNEOUS ROCKS
2. SEDIMENTARY ROCKS
3. METAMORPHIC ROCKS
IGNEOUS ROCK
Igneous rocks are formed by magma from the molten interior of the Earth. When
magma erupts it cools to form extrusive or volcanic rocks. If magma cools inside
the Earth it forms intrusive rock, plutonic which may later be exposed by erosion
and weathering.
Example of intrusive igneous rock is: granite.
Examples of extrusive igneous rock are: obsidian, pumice and basalt.
SEDIMENTARY ROCK
Sedimentary rocks are formed from sediments that have settled at the bottom of a
lake, sea or ocean, and have been compressed over millions of years. The
sediment comes from eroded rocks carried there by rivers or ice, and from the
skeletons of sea creatures.
Examples of sedimentary rocks include conglomerate, sandstone, clay, chalk and
limestone.
METAMORPHIC ROCK
Metamorphic rocks have been subjected to tremendous heat and/or pressure,
causing them to change into another type of rock. They are usually resistant to
weathering and erosion and are therefore very hard-wearing.
Examples of metamorphic rocks include marble, which originates from chalk rock,
slate, schist and gneiss which ones originate from clay and quartzite which
originates from sandstone.
Provincia Marista Mediterránea |COLEGIO MARISTA NTRA. SRA. DEL CARMEN| Badajoz
Avda. Juan Pereda Pila, 14 CP 06010 - Badajoz - Tfno. 924 230 280 - Fax: 924 20 71 23
www.maristasbadajoz.com | [email protected]
GRAMMAR: ------------------------------------------------------------------------------------(SPANISH)
LISTENINGS:
VIDEO: TYPES OF ROCKS AND ROCKS CYCLE
https://www.youtube.com/watch?v=XxoSUgIgQF0
ACTIVITIES: Draw a scheme about types of rocks.