3
The Geosphere
124
WORK AND EXPERIMENTATION TECHNIQUES
The texture of rocks
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.
In addition, it will help students to become familiar with materials
and instruments used in a laboratory such as the binocular loupe.
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.
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.
2.
What are themaindifferences between conglomerates
and sandstone?
Mainly the size of the grain, bigger in conglomerates.
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.
64
65
3. Thegeosphere
3
The environmental impact of mineral extraction
FINAL TASK
The texture of rocks
WORK AND EXPERIMENTATION TECHNIQUES
1.
Which of the observed rocks is homogeneous? How did you know?
2.
What are the main differences between conglomerates and 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 science practical, define in your own words the different types of rocks (igneous,
sedimentary and metamorphic).
5.
Which of the rocks observed were formed in the exterior of the Earth’s crust? And in the interior?
1.
Puteach rock,onebyone,on theslideof thebinocular loupe.Look through theeyepieces
and move the macrometric screw until the rock is sharply focused.
2.
Observe each rock, and draw what you see for each rock.
3.
Place a ruler next to the rock and, with the help of the loupe, measure the crystals
or fragments that compose the rock.
4.
Do another drawing of each rock observed.
Procedure
Somecharacteristicsof rockscannotbe seen justby lookingat
them. In this sciencepractical,youwill learn touseabinocular
loupe to compare different rocks and distinguish them
according to texture.
Materials
❚
Binocular loupe
❚
Five different rocks, for example,
conglomerate, sandstone, basalt,
granite and gneiss
❚
Ruler
Textureof conglomerate
Textureofgneiss
Textureof sandstone
To analyse the results and compare the rocks, use the following table next to your drawings:
Analysis of results
Name of rock
Minerals it is
composed of
Size of the
components
Type of rock
...
...
...
...
Follow these steps for your research:
Research
❚
Find at least four different ways in which mines impact the environment and people. Suggest some possible solutions
to the problems.
❚
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.
Procedure
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.
a)
Whatare thenegativeeffectsofmineralextractionon theenvironment?
b)
What is coltan andwhat it is used for?
c)
Where are themain coltanmines located?Are there any in Spain?
d)
How does the behaviour of the consumer affect the exploitation of
children in coltanmines?What canwe do to help solve this problem?
1. Research
a)
Prepare a slideshow presentation.
b)
Make a list of three ways in which we can contribute to the
sustainablemanagement ofmineral resources.
2. Tasks
❚
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?
SELF-ASSESSMENT
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