martes, 9 de diciembre de 2014

The Minerals

            MINERALS

         In this unit we are going to open a door into a fascinating world. The world of minerals. It tends to be apalling and attractive for students and teachers. Its target students are from a level o 1st ESO. Students are going to learn about minerals and its composition and inherent characteristics of minerals, properties, exploitation and usefulness. Moreover, we will see different methods of extraction with videos.
It will take three sessions to complete our unit although there are some extra materials for outstanding students.




You have all the links in this unit organized and collected at this site:






                                   Session 1 




Presentation with the video :





Then you have the tapescript of the video to comment and make some questions.

Tapescript (pdf):
Earth Materials
What do you think of when you hear the phrase 'natural resource?' Many people think of something that comes from Earth and that we as humans do not make ourselves. The Earth has many natural resources, known as Earth materials. There are four main resources, and they include minerals, rocks, soil and water. These four resources work together to form and sustain the majority of life on Earth.
Although these four resources are the most common, there are other Earth materials that are important and unique. Let's examine two additional types of Earth materials, known as metals and precious rocks.
Metals
First, let's examine metals. Metal is a substance that frequently has a shiny surface, conducts electricity and heat, and can be melted and shaped. If you look around you, there is most likely metal somewhere in your view. Although we mainly think of metal as a construction material or a component in electronics, there is actually metal found naturally within the Earth. Metals are essential nutrients that organisms need to grow and survive and are necessary to maintain healthy ecosystems.
Most metals are extracted from ores. Ores are naturally-occurring rocks that contain metals and other minerals. A rock is considered an ore if it contains a large amount of the metal and if that metal can be economically extracted from the rock. Basically, there are many types of rocks that contain metals, but some only contain small amounts, so it is not worth the expense of extracting the metal. When extracting metals, people look for large concentrations of ores so that they can make the largest profit for the extraction effort.
Humans extract metals from the Earth for a variety of reasons. One of the most famous natural metals is gold. During the Gold Rush, people traveled across the United States in hopes of extracting gold from the land and becoming wealthy. Other natural metals include aluminum, which is used to make cans, copper for wiring, lead for batteries, silver for jewelry, and iron for steel.
Precious Rocks
Now, let's examine precious rocks. What does the word 'precious' mean to you? Although most of us do not describe rocks as precious, some rocks are. Precious rocks are stones that are very rare and have economic value. Precious rocks are also referred to as 'gemstones' or 'jewels.' These stones gain their economic value due to their aesthetics, or natural beauty. They are also very durable and difficult to break or scratch. Precious rocks are commonly used in jewelry but are also carved or inserted into artwork or furniture.
Precious rocks come in many different colors, shapes and compositions. These stones also formed in a variety of manners. Most precious rocks are formed when a rock is exposed to a change in temperature, pressure or interacts with another solution. Some stones are even formed within the molten magma of volcanoes!
We have time to introduce vocabulary of the unit and comment on some doubts they may have about the readiing.at the same time, we make a presentation of the unit.

Make questions to check their understanding.Introduce new vocabulary.
Promote a debate about the importance of minerals.
To introduce the next session:
In this video they see the properties of minerals.
 
                                               Session 2

1.     Characteristics of minerals

Write them down in you notebook.
2.     Types of minerals

Make a chart with bubbles .

We have further materials to widen :


                                               Session 3

Extraction and processing

About minig process.
Tapescript we provide as a pdf:

Extracting Surface Minerals

Surface mining is just what it sounds like - removing minerals that are near the earth's surface because this is where the ore deposits are located. When the ore deposits are very large, open-pit mining is utilized. A large, open pit is created as machines scrape off any earth that is not ore and set it to the side. This material is called overburden, and as the overburden is scraped off, it's piled into spoil banks.
After the overburden is cleared from the ore, explosives are used to break up the ore material that is being removed from the ground, which is then taken away to be refined. The size of the ore bed increases as mining continues, and eventually, the pit becomes a very large bowl-shaped hole in the earth's surface. When the ore is found in a wide area but it's not very deep in the ground, strip mining is used.
In strip mining, instead of creating one large pit in the ground, long narrow strips are dug out. The overburden is removed and piled up along the strip. Once the ore is removed, the overburden is dumped back into the strip. While this may sound like a good method because the holes are re-filled instead of left open, the land actually looks more like a washboard after strip mining because of all of the re-piled soil.

Extracting Minerals Deep Underground

Some minerals are found very deep below Earth's surface - sometimes hundreds or thousands of feet deep! To remove these minerals from the ground, subsurface mining is used. In subsurface mining, a long tunnel is created either horizontally or vertically. The tunnel walls are reinforced with wood and ventilation shafts are created to provide air to the miners underground. The minerals themselves are removed a number of different ways.
One way is to blast apart the material and then send the ore pieces up to the surface in carts. Another method is longwall mining, which is when coal is sheared from the wall and collected on a conveyor belt, much like a potato peeler shears away layers of a potato. This is a very efficient way of extracting coal from an underground mine. Another method is solution mining, which is when hot water is injected into the ore to dissolve it. Once the ore is dissolved, air is pumped into it, and it's bubbled up to the surface.

The Harmful Effects Of Mining

While mining provides us with the minerals we need, it is also very destructive because it disrupts the landscape both on the surface and underground. It also causes quite a bit of pollution and can harm or kill mine workers. Surface mining is destructive to landscapes because it can cause changes in the topography and drainage and strips the land of vegetation, soil and rocks. The spoil banks of surface mining erode and weather away, and rainfall leaches toxic chemicals into the earth. In some cases, entire mountaintops have been removed for surface mining!

Further materials to deepen for outstanding students:







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