Wednesday, June 5, 2013

NTU Flagship: Day 2

8A - Tensile Testing of Engineering Materials
8B - Scanning Electron Microscope (SEM)
8C - Composite Material Processing

Teacher Advisor:

Ms Teo Wei Ting

Today was a good day. All the activities were interesting and I had a bit of prior knowledge about some projects for example I had a rough idea of how epoxy works and how to use fiberglass. The break times were appropriate and I also gained some additional knowledge about science during the last session.

For the first experiment/activity, I learnt about practical uses of Fiberglass and Carbon Fiber. They are relatively lightweight and very strong. Composites are combinations of two or more materials to get desirable properties that materials do not have individually and are used in modern planes (cannot be fully made of composite materials) and even racing cars to make them lightweight yet strong. We got to make our own Fiberglass and Carbon Fiber using epoxy and bring a piece back tomorrow.

For the second experiment/activity, I learnt about how to test for the yield strength, ultimate tensile strength and breaking point of a material. The width and thickness are measured and a graph is plotted on the computer about the different points and strengths of the materials during the respective tests. We tested mild steel bar, aluminium-copper alloy bar (code 6061), polyethylene bar and PMMA (Poly methyl methacrylate) bar. In real life applications, materials are roughly tested like this to see which material is most suitable for a specific purpose.

For the last experiment/activity, I learnt about how Scanning Electron Microscopes (SEM) work, how to operate them and what they are used for. The SEM has an electron gun which creates an electron beam to stream down the electron column and observe the surface morphology and elemental information of the object. It has a very high resolution (<1nm) but also has its limitation. It cannot zoom to the atoms of the object. Specimens are coated with gold to conduct the electrons and prevent the electrons from burning it away. We also got to try a virtual experiment since we are not qualified to operate the actual SEM. We got to see a demonstration of the instructor using the actual SEM and it is roughly how it is in the simulation.

Overall, these activities are those few that I gained the most knowledge about science from and I gained a lot of valuable experience. Those are very applicable in real life situations and I would definitely apply those knowledge in the near future.

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