METALS. MIND MAP

Mapa Mental creado con GoConqr por Marta Profedetecno

What is a pop rivet?

Metals can  be joined together by  permanent or temporary  joints.

Some permanent  joints are made by  rivets.

For this joint  we need a riveting tool. At  first glance, it is not easy to understand how this tool works. This video shows us quite explicity how it works.

 

RUSTING EXPERIMENT

Rust is usually used to refer to a very common, reddish-brown compound called iron oxide (Fe₂O₃). Iron oxide is formed when iron and oxygen react in the presence of water or moisture in the air. Rust occurs when iron or its alloys, such as steel, corrode.

 

The process of rusting is a combustion reaction, similar to fire. Left in contact with oxygen, iron will react with the oxygen to form rust. 

 

There are certain factors that can speed up the rusting process. For example, water speeds up the reaction. Other substances, such as salt, can also increase the speed of the rusting process.

This experiment will help you to find out what caused rust to occur:

 

MATERIALS:

5 glasses (transparent), steel wool, water, salt, bicarbonate of soda and vinegar.

PROCEDURE:

1. Line up the glasses and label each one as 1, 2, 3, 4 and 5, so that you can write down what you have put in each.
2. Put a bit of steel wool in each container.
3. Pour some water into your first glass labelled '1' and put the lid on it.
4. Leave your second glass labelled '2' open and exposed to the air  (air contains water vapour).
5. Mix some salt with some tap water and pour this into your third glass labelled '3' and place the lid on it.
6. Add a pinch of bicarbonate of soda in your fourth container labelled '4' and place the lid on it. (bicarbonate of soda may help to remove water vapour from the trapped air).
7. Pour some vinegar into your fifth glass labelled '5' and put the lid on it. 

Observe the glasses the following day and write down your observation.
Clue: Container '4' will only start to show rust if the air and any water vapours get through the lid into the glass.
 

SUMMARY OF METALS

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It is not  easy to   find in  nature Metals in their pure form. They are usually alloyed with  other  metals.

The metals group has some common properties:

Mechanical properties	They are hard, tough and can be malleable and ductile.
Thermal properties	They  are conductors of heat; depending on the temperature, they expand or contract  and can  be soldered easily.
Electrical and magnetic properties	They are good conductors of electricity; some  are magnetic, for example iron and cobalt.
other	They  rust easily, conduct sound and are solid at room temperature.  They  can  be recycled and reused. Some of them, such as lead or mercury are toxic for the enviroment.

According to their composition, metals can be classified as:

• Ferrous: if they  contain mainly iron. 
• Non ferrous: they  don’t contain iron.

Ferrous  metals: are formed by iron and its alloys with carbon. dependding on the percentage of carbon alloys of iron  are classedas:

Pure Iron	It contains less than 0.03% of carbon. It’s brittle and doesn’t have many applications.
Steel	It`s Made mainly with iron and 0.03% to 1.76% of carbon. It’s tough and easy to  work with. It’s widely used.
Cast Iron	It's made from iron and 2% to  6.67% carbon. It’s very hard but it is not tough as steel.

There are many  non ferrous metals. In this unit  we have studied:

Copper	It’s a very good conductor of electricity. It’s very  ductile and malleable and can be shaped easily.
Tin	It’s easy  to  work with and melt. It’s used as a filler metal to soft soldering. When it is allowed with cooper it is called bronze.
Aluminium	It’s very light, highly resistant to corrosion, non toxic and easy to shape. It  has many  applications.
Zinc	It is malleable, ductile and very  resistant  to corrosion. It is mainly used to protect others metals  from rust. When it is allowed with  cooper is called brass.

Before working  with metals, we must  know which tools to  use.

Measurements and layout	Ruler, set square, steel tipped compass, centre punch.
Holding and bending	Gloves, jack, vice, pliers.
Cutting	Pliers, tinsnips.
Perforating	Punch and hammer, drill.
Filling	File.
Joints	Rivets, glue, soldering, nuts and bolts, pins.
Treatments	Rust-inhibiting paint, chrome.

To learn more about metals

Have a look this web page where you can  find more information about  the classification of metals in two  groups Ferrous and non-ferrous metals and its main  properties

BBC - Metals 

Here there is a nice video about  Ferrous Metals:

And this video it is about Non Ferrous Metals

 

 

Las Médulas

The Romans mined large quantities of gold and silver in this region in north-west Spain, along with others metals like cooper and iron, using a technique based on hydraulic power.