Everything that we see or feel or interact with is made up of some material, whether it is a solid material, a liquid or a gas. So what exactly are materials made of?
Well...this depends. But good answers would be atoms, molecules, particles, crystals, electrons, protons and neutrons. Because different materials can be made up of different things. And this changes the properties of the material, making each material different to another.
So how can we describe different materials? Again, there are different ways of how we can describe material properties. But good answers would be weight, magnetic properties, electrical or thermal conductivity, colour, density, strength, chemical composition, hardness and the list goes on and on.
A materials engineer would learn how to study these properties to develop better materials for different applications. And one way to do this is to look at different materials through different magnifying tools.
Observing materials through a stereo microscope
A stereo microscope lets us magnify objects up to about 600 times. This lets us understand the structure of matter.
Have you ever tried to swat a fly? They always seem to be able to see you coming. If we look at the eyes of insects, we notice that these are ordered as a hexagonal array. The way the insects' eyes are structured determine the way light travels through to the insects' eyes and this is important for their survival.
These pictures are of a moth seen at different magnifications we can see the hexagonal array clearly at high magnification!
Why would engineers look at insects' eyes?
Engineers often look at the way nature works to copy and develop materials. This is called biomimicry. For example, by copying the structure of insects' eyes, engineers have developed antireflective materials without the use of chemicals or coatings. This concept has also been used to produce more efficient PV panels.
Observing materials through an optical microscope
To look at things using a higher magnification, the Optical Microscope is a better tool to use. The Optical Microscope can magnify an image up to 1,000 times. In other words, 1mm can be magnified to look like 1m. Looking at different metals and their microstructure, one can identify the type of material and even have an idea of its hardness and chemical composition.
Observing materials through a scanning electron microscope
If we want to look at things at an even higher magnification, we can use a scanning electron microscope or SEM in short. This is different from stereo and optical microscopes because instead of using light to look at things, the electron microscope uses electrons.
With an SEM we can magnify objects by 1,000,000 times. That's right! With the SEM, 1mm can be magnified to look like 1km. The SEM gives us the ability to see structures that are just a few nanometers large.