Using all of the information that I have collected and presented throughout this project I will answer some key questions about aluminum. Over the course of my investigation into Aluminum I have used these questions to channel my lines of enquiry to provide the most thorough answers possible, and to give my research a focus.
How does aluminum avoid corrosion?
Aluminum forms a 1 nm (or sometimes slightly thicker) layer of aluminum oxide on its surface when it is exposed to air. Even though aluminum is reactive this oxide layer prevents the actual aluminum making contact with other elements which it could react with. In this way aluminum avoids reaction and corrosion. This is a particularly important feature for aluminum is its outdoor uses where being resistant to weathering is essential. If the layer breaks it immediately reforms when the aluminum is next in contact with oxygen.
Why is aluminum used so much in transport?
Aluminum is a low density material which gives it its lightweight property. When mixed with other elements in alloys it is also very strong. This unique combination of strength and weight is essential for the transport industry. As Force = Mass x Acceleration, the bigger the mass the more force will be needed to achieve a certain acceleration. This means that using aluminum is transport vessels saves money on fuel, allows more cargo to be carried, and is better for the environment. Aluminum's corrosion resistance perfect this profile making it absolutely ideal for its uses in aeroplanes, trains, cars, and ships.
Why is aluminum so reflective?
Aluminum can reflect up to 97% of light that falls upon it when highly polished, but how does it do this? Reflections occur when light hitting a material provides enough energy for an electron to move to an excited state, from where it emits a photon of light upon returning to its ground state. In aluminum there are many electrons that are free to easily become "excited" like this, this makes it an extremely good reflector.
Why is aluminum not magnetic?
In all materials electrons orbit atoms, and as each of the electrons has an electric charge each of these electrons produces a tiny magnetic field. In most materials electrons pair up in energy sublevels with opposite "spin" properties, so the effect of their tiny magnetic field is cancelled out by each other. However in some materials the electrons frequently don't have to pair up so an overall magnetic field can be created if a magnet forces the electrons to align in the same direction which it does in metals like iron. In iron and steel some electrons stay aligned, and this is why large magnets are often made out of these materials. In aluminum the electrons don't give an overall magnetic field in one direction, so it isn't magnetic.