Metal - how it is used Science Gr 4-5

We learned in the previous lesson about the differences between metals and non-metals.  

                                      

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These two groups of materials have many uses depending on what you want to use it for.  

You first need to decide what is the purpose of the material (must it be strong, flexible, water resistant etc.) and then you can decide which material you are going to use to produce (make) something. 

Different properties and uses of metals

Lets have a look at the different uses of metals.  Their special properties make them suitable for many uses.

1.  Metals and magnets

Different metals have different magnetic properties - this mean some will be attracted by a magnet and some will not.

Watch the video for more information

2.  Metals and heat 

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Metals are good conductors of heat which means the heat will move through it quickly.  Metal will also expand (become bigger) if it is heated.

Different metals have different rates of conductivity - this means that heat will move faster through one metal and slower through another.  In order to find out which type of metal is the best conductor of heat you can do an experiment

3.  Corrosion of metals

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Corrosion means that metal will become less shiny like when they are new and the metal will start rusting and breaking up.

Rust forms when iron corrodes  and it has a reddish brown cover and a rough texture.

The iron reacts with the oxygen in the air or in the water and a chemical reaction takes place and iron oxide (rust) forms.

Different metals corrode in different ways

1. Silver will tarnish
2. Copper objects will get a green coating called patina
3. Brass will get black spots
4. A grey coating will cover aluminium and this is called aluminium oxide

• find a picture of each of these types of metals and what it looks like if it starts corroding

If you look at new and old copper coins you will see that the new coins are shiny, but the old ones are dull.  We can clean metals in different ways.  Have a look at how you can get your coins all shiny again

Metals can be used for different things

Metals have thousands of uses and we use it every day.  Sometimes we will even use it without knowing.  Here are some uses of metals

• the cables used to transfer electricity is made of metal
• metal can be made into sheets and these sheets can be used to build cars, trucks, trains and aeroplanes
• metals are very strong and can be used to build structures such as bridges or metal roofs and window frames

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