Venue: NUS
Time: 2.30–6.00pm
Today, I went to NUS to meet up with Professor Huang and Professor Li to conduct some experiments and enquire some questions about undergraduate physics. I also plan to ask them questions about potential topics to write my Extended Essay I need to write next year during IB.
Firtly, I was taught by Professor Li. He wants to show me an experiment about the electromagnetic force. I learnt about three types of magnets, ferromagnetic, diamagnetic and paramagnetic. Ferromagnetic materials can be grouped into two distinct groups, unmagnetised and magnetised materials. Unmagnetised ferromagnetic materials have an overall charge of zero, meaning that on a microscopic scale, they have a specific direction the magnetic domain that points to the same direction. However, if I zoom out, I will find out that some parts of the ferromagnet has the opposite direction, hence creating an overall zero charge. Next, we used a microscope and observed five such types of ferromagnetic materials. I observed the intricate patterns of the magnetic domains, indicated by the dark and light yellow areas on the ferromagnet. After that, I tried to bring a small magnetised ferromagnet towards the unmagnetised one. Interestingly, I discovered that the patterns on the unmagnetised ferromagnet changed, with the darker area of yellow becoming thinner and thinner, eventually the lighter areas took over the whole place.
I was told by the professor that the round metal magnet has a south, north pole and that the direction of flow is from the north to south pole. Therefore, when it is brought close to the unmagnetic ferromagnet, all of the magnetic domains aligned to the same direction as shown in the picture below. If I reverse the direction of the magnet, the darker areas will take over the whole place as the direction of magnetic domains align. When I questioned the professor about the approximate size of the magnetic domains, he suggested me to use my strand of hair as a comparison. Although it was very hard to secure my strand of hair, I managed to view my hair as a very thick strand under the comparatively small magnetic domains.
The professor told me that my hair is approximately 50 micrometres. Therefore, I can deduce that the length of one magnetic domain is about 8 micrometres, because there are approximately 6 lengths of domain cover the width of my hair. The picture below shows the width of my hair compared to the magnetic domains. Furthermore, I attempted to view the details of my hair under the highest magnification (x100).
I was told by the professor that the details inside the hair is due to a protein called keratin, and now I am seeing the intricate patterns of keratin.
Next, I had a chat with Professor Huang about my my Extended Essay. At first, I was going on about how I can test out the properties of graphite in my EE, for example, the strength, the conductivity etc. Additionally, I suggested that I could use graphite to replace the separator in lithium-ion battery. However, he advised against it because he said I will take too much time doing that, and I should switch to an alternative experiment, one that is much more straightforward and takes less time. He suggested me looking at the strange phenonenum of everyday life and start from there. After that, we started brainstorming ideas for the possible topics for EE. In the end, after multiple failed attempts, I came up with an idea about the ultimate lunch angle for a projectile so that it can cover more range. However, Professor Huang said that the experiment is too common and asked me to come up with another aspect of the experiment. In the end, after a few trial and error, I ended up deciding to investigate how the effects of air resistance affect the total range covered by a projectile. I planned to devise a formula for the range covered under the influence of air resistance.
All in all, this visit has let me gained deeper knowledge and understanding towards physics as a whole and definitely piqued my interests in the subject. Therefore, I am more confident to handle the Extended Essay because I had a rough idea of what I want to do.
