My Application Experience to Oxford for Undergraduate in Physics

Disclaimer:
This blog is about my personal application experience to Oxford Undergraduate Physics Department. This blog is not an official guide on admission process to Oxford, and it does not represent opinion from Oxford Admission tutors themselves.

Pre-interview and a little bit of intro into Oxford (and Cambridge)

I will try not to duplicate any info that readers can find by simple googling. For those who are unfamiliar with admissions process into Oxbridge (Oxford and Cambridge, people combine them into a single word because these 2 universities have the very similar (and unique) system that is really different from the rest of universities in the world), click on this link before you proceed. The link provides a very comprehensive info about general info on Oxbridge application. Before the interview, I had taken PAT (Physics Aptitude Test) a month ago, and scored reasonably well to get shortlisted for interview.

What I love about Oxbridge (besides reputation) is the idea of being taught by experts from physics (tutorial system), often on 1-on-1 or 1-on-2 basis. Oxbridge have a very, very low tutor to student ratio (1:1 / 1:2 / 1:3 ) and this means that those experts (for my case, world-class researchers and physicists) take a personal interest into your progress (How sweet is that, haha!!!). And for a theoretical physicist, having a great sifu (mentor in Chinese) is really essential before developing intuition and persistence needed in physics research.

Part One: Personal Statement (UCAS)

For my personal statement I mainly wrote about my passion in physics and what are the aspects in physics that excites me. I think the most important message for prospective applicants to include in personal statement is to demonstrate their interest for the course they are applying to. (Note: saying that “I’m interested to study blah blah blah because” and demonstrating passion in personal statement can be very different.)

My personal statement utilized a few aspects/ ideas to demonstrate my passion and aptitude for physics.  In my statement, I wrote about how my interest in physics started when I watched MIT physics lectures and how those counter-intuitive and cool demos by Prof Walter Lewin challenged my intuition and imagination about the world around me (You’ll probably want to watch his demos, rest assured, they are really mind-blowing and cool!) I went on to write a bit more about leisure readings related to physics outside of standard school syllabus and discussed a bit on “The Fabric of the Cosmos” ( semi-academic book by Brian Greene, intended to spread ideas like quantum mechanics to layman audience) and how this book stirred my curiosity and led me to keep questioning everything around me.

The next thing I wrote about is my involvement in science and math related activities and achievements and how these experiences convinced me that physics is the right thing for me to pursue at undergraduate level and beyond (I aspire to be a research physicist one day). I mentioned about mathematics competitions and how solving those “unusual” problems compared to problems in standard school curriculum sharpened my creativity and changed my perspective about problem solving in general.  For math-science related activities, my involvements in math club and tutoring are my channels to spread my passion and love for physics and mathematics to peers around me.

While I think this is optional, maybe applicants can include activities not related to their intended major, but care must be given not to write too much about, say, your achievements in football to the extent that it strays from original purpose of statement, which is to demonstrate passion.

To sum up, personal statement is about one thing: showing your passion.

Part Two: Admission Test

I wrote this part exclusively for application to Oxbridge (for most UK universities submitting UCAS online is suffice, but for Oxbridge they do have written tests and interviews as part of their selection process), and in my case, application to physics at Oxford (Note: Engineering, Material Science and Physics and Philosophy applicants to Oxford will need to sit for the same PAT test (Physics Aptitude Test) as well.)

So, I sat for PAT in early November during my application year to Oxford. Regarding to preparation for PAT, I think my advice will be somewhat generic: practice PAT style problems (from past PAT papers or British Physics Olympiad (BPhO) AS Challenge Problems) (Note: Just a bit of extra info, Oxford Physics Department is responsible for selecting British pupils to represent country for IPhO at international level, so they set national level Physics Olympiad problems and the ‘flavor’ of BPhO AS Challenge problems are much similar to what you’ll expect for PAT). As for the level of physics you need, I will advise people who have not attain enough prerequisite knowledge to do some self study before the test (sufficient level of preparation for physics is up to core syllabus of A2 Physics for Cambridge A Level, all the way to quantum physics in A Level). While for math part of PAT, you need to know your AS level Mathematics as well as how to solve some “probably” unusual problems.

So, the best way to prepare is: practice.

Part Three: Interviews

Here comes the part of application process that I enjoyed the most: Oxford Physics Interviews (and probably the most important part in your application)

For those who achieve passing score for PAT (Oxford shortlists from over 1100+ physics applicants to about 500 applicants for interview, you can refer to Oxford Physics admission statistics for further info), you’ll be emailed and called for interview(s). For those who’ve arrived to this stage: Well done and reward yourself some cookies J! I will start by writing some general interview advice for Oxbridge (Oxford and Cambridge) interviews and later on pinning down the details of my personal experience for Oxford interviews.

The general bits

Here are a few personal qualities that are important (my personal opinion, of course):    

1.) Demonstrating passion and clarity of thoughts.  Essentially, you will need to show that you’re really excited about the course that you’ll be studying at university. While personal statement is a way to show passion, I think it’s also important to show that you love your course and to show that you’ll be able to think critically about your subject through interview. During interview, a great way to break the awkward silence when you’re being interviewed by your interviewers is thinking aloud, by telling them what you think, and telling them why you think and argue about certain arguments in a certain way and how you arrived to the conclusions you’ve made. Ultimately, the interviewers are not interested in whether or not you’ve arrived to the correct solutions/ answers for interview questions, but they’re more interested in your thought process and the way you build up your arguments and reasoning. And also, speak out any assumptions you’ve made in your reasoning.

2.) Potential. During interview, it’s much more important to show your potential than to tell them your achievements thus far (you’ve probably included your achievements in personal statement so it’s best probably not to duplicate information while wasting your interview time). The tutors and interviewers are more concerned about how much you can grow and learn from them than how much you have achieved, which leads me to the next point.

3.)   Being teachable is really, really important. The interview is actually very similar to how tutorials are conducted at Oxford (or supervision at Cambridge), so the tutors are essentially choosing the students they'd love to teach for the next 3 or 4 years. If you enjoy the interview, you will probably enjoy the next 3 to 4 years of intellectual conversation with your tutor at Oxbridge. Basically I treat Oxford interview as an opportunity to learn physics from world class physicists, and that alleviates my nerve and stress before the interview while keeping me excited for the interview. And of course, you must be able to communicate your idea clearly, and don't be shy to ask for hints/ clarity in case you're stucked in the interview.

Another point to note: Don't freak out if you are unable to answer interview questions from Oxbridge. Oxbridge interviews are meant to push students beyond their limit and boundary, so that the tutors can assess the potential of students and how much students can be stretched. This is what the tutors actually aim to do, to see how far students can handle unfamiliar scenarios/ situations. The tutors certainly are not looking for what you have already known, but they are looking at how teachable you are and how much potential you have in the subject you intend to study at university (for my case, Physics).

The specific and personal bits

1st Oxford Physics Skype Interview (Conducted by Physics tutors from University College, Oxford)

I applied to University College (informally known as ‘Univ’) at University of Oxford, and as part of Oxford Physics department admission process, I was interviewed twice, once by ‘Univ’ and another interview by a second randomly assigned college (for my case, Pembroke College). Unlike Cambridge (where Malaysian applicants can choose to either fly to Cambridge for interview or had the interviewers coming over to Malaysia), Malaysian applicants to Oxford can only choose to either fly to Oxford for interview or have their interviews through skype. I opted for skype interview and I will write about my first interview here.

Okay, done with the explanation, now I will write about my personal experience about Univ interview. My interview lasted for 45 minutes and I will pick a few interesting problems for reader to see.  My interview revolves around interesting problems and phenomena around physics and mathematics.

An Integration Problem with Nice Clever Trick

After receiving this math problem, I’ve thought of standard substitution method and told my interviewers why substitution method works. But after working through the substitution method I’ve realized that I’ve worked through the problem longer than it should be. Hence, out of my curiosity, I asked my interviewers for hints as if there were other approaches to this problem (After all, math is about flexibility and math is beautiful because we can approach problems in many ways. J ), and I was shocked at how elegant and simple my interviewers would have otherwise solve it, here’s the hint (spoiler alert for people who try to solve this!):

I was awestruck at how simple this hidden pattern is! This approach is much shorter and elegant (In case you haven’t realize it, it’s simply has (1/x) and differentiated form of (ln x) and integral in the form of f’(x) / f(x) will result in ln ( f(x) ).).

After speaking out my thoughts and approaches on several math problems, the interviewers moved on to a physics phenomenon: moving charge in magnetic field. Rest assured, the interviewers didn’t just ask about issues and problems in which you can find in your standard A-Level syllabus, they went beyond and tested me on how much I can adapt and solve the unknowns. The interviewers started with standard A Level magnetic field case (where moving charge is moving perpendicular to magnetic field, in circular pattern) and moved on to moving charges moving at an angle (not perpendicular as in first case) inside uniform magnetic field (unusual to A-Level syllabus but if you break down the velocity component into horizontal component and realized that the component perpendicular to field will move in circular motion while parallel component will move in constant velocity, which resulted in helical motion). I will move instead to last part of this interview problem where I’ve spent almost 10 minutes struggling to understand:

(The problem is about predicting the motion of positive moving charge coming at an angle inside converging field)

On my previous 2 cases, I’ve only dealt with uniform magnetic field, and now I was asked about what will happened to the motion and trajectory of a moving charge coming at an angle to a converging magnetic field (see pic above). This is rather strange physical phenomenon where I’ve never thought about it before and I thought it would be interesting to speculate and predict the motion of moving charge. First, I’ve stated that magnetic field strength is increasing (since field is converging) but I’ve struggled (in a rather unfruitful direction) for first five minutes on this problem. Finally, I’ve asked for one hint, and it’s this one hint, that led the way to understanding and solving this problem.

The hint is: The Lorentz force acting on positive moving charge, in real mathematical form, is cross product of qv and B ( F = qv X B). While this hint was obvious to me, I never thought that this hint was rather useful in handling this problem. Then, I’ve come out with a sketch of my solution while explaining verbal what’s going on (see pic below):

This is on why the hint is useful:

As you see, the cross product will change the perpendicular component of velocity and since the field strength is increasing, it will “attract” the vector of velocity towards the perpendicular component towards itself. But the cross product constraint will require that the magnitude of velocity stays the same and hence it resulted in a rather weird helical motion which will eventually result in circular path. I’ve spent around 10 minutes speaking out my though process, assumptions and reasoning on interviewers on this problem and realized I enjoyed the experience and learnt new physics along the way! (For those who are interested in greater depth on the mathematical details of this phenomenon, it’s called Magnetic Mirror and you can find out more by googling.) 

Another version of explanation (hope this will clear up any doubt):

As the converging magnetic field implies that the magnetic force (which is common perpendicular to both field lines and velocity) is increasing, this will thus increase the perpendicular Lorentz force to the velocity (The direction of Lorentz force (which is always perpendicular to velocity) will have some complicated change in direction due to the change in velocity and increasing in magnitude so I will not show the details but the big picture.). Drawing perpendicular force with analogy of centripetal force acting perpendicularly on velocity, stronger centripetal force will cause some sort of spiral-in effect due greater change in perpendicular component of velocity due to acceleration. In 2D spiral-in motion, the magnitude of velocity increases due to increasing centripetal force (centripetal acceleration = r*w^2, while circular radius decreases the w need to increase more than r in order to account for increasing centripetal acceleration) (this corresponds to increase in perpendicular component of the motion of charged particle in converging magnetic field). But the Lorentz force (in this 3D situation) is cross product of velocity and field line and magnitude of speed needs to be constant. In order to accommodate the effect with increasing perpendicular velocity component, the horizontal component of velocity needs to be reduced to keep the magnitude constant.

2nd Oxford Physics Skype Interview (Conducted by Physics tutors from Pembroke College, Oxford)

My 2^nd Skype interview was held 2 days after my first interview. Compare to my first interview, I would say that this interview was much ‘quirkier’ in a sense that the questions are rather much more open-ended and required general mathematical aptitude rather than specific mathematical techniques.

Of course, in this section, I’ve handpicked interesting problems as well to present my interview experience. Here’s one of the weirdest interview questions:

At first, this problem appeared to be too broad and I thought of too many approaches (that didn’t work out that well, somehow). While this problem appeared to be too broad and I didn’t know where to get myself started, I’ve instead made some assumptions. I clarified that the sunlight shines at some small angle to London while it’s directly above Paris and assumed that the distance between the city was just a very little minor arc of earth surface (and can be approximated as straight line) and the interviewers immediately corrected me on these 2 faulty assumptions.

So, my corrected assumptions are as below:

a.)   Sunlight is assumed instead to come in parallel straight line

        b.)  Earth is perfectly spherical and 2 cities and located at 2 points on minor arc (See pic below)

After I’ve been corrected on my assumptions, I was immediately enlightened about the right approach to this problem. By utilizing general geometry principles about parallel line, I could work out the distance arc (which is the distance between London and Paris). 

This is a big problem with 4 sub-problems, but I’ve picked up the interesting piece of sub problems to write about it here (2 of the 4 sub problems here). While I was unsure about the term ‘Flux’ in the context of problems, the interviewers clarified it and in a more mathematical language, it’s simply the rate of change of volume (flow rate). After clarifying the word ‘flux’, I went on to solve this problem by modeling it using differential equation. In case you are interested in how h(t) can be obtained, here’s the solution:

After solving it, I immediately realized it’s negative exponential function and went on to solve the 2 subsequent sub-problems during the interview. The interviewers final question (arguable one of the toughest) was:

While I struggled to imagine the general picture of the curve, the interviewer once again enlightened me by asking me 2 questions:

      a.) What happened to the beginning of the curve and how it should looked like?

b    

      b.) When almost all water from 1^st Jar has been transferred to 2^nd jar, how should the water level on 2^nd jar dropped?

For the first part, I figured it will look almost like some sort of increasing exponential shape and for the second part I figured it will look almost like negative exponential(not exactly because while water is filling 2^nd jar water is flowing out at the same time so the exact curve shape and equation will be different) and here’s my sketch (of course, my assumption is that when water in level is falling exponentially it will come to a point where it can be approximated as 0):

After I’ve sketched this last sub problem, 30 minutes had passed and the interviewer ended the interview. In general, I loved the kind of intellectual conversation going on in both interviews and I couldn’t wait to see myself engaged in this kind of conversation in next 3 to 4 years in Oxford tutorial system with my tutor. These problems, once again, broadened my problem solving perspective and I must say that I loved it.

Part Four: Conclusion

For my last words, I will advise and say that the best preparations you can do to get into Oxbridge are: 

            

      1.) Not being afraid to explore and think about new ideas and issues

      2.) Learn to communicate clearly and clarify your thoughts during interview

      3.) Mostly important, apply to the course you’re really passionate about! As the famous saying goes “Love what you do, or leave.” I believe this doesn’t apply just to scientists but also to all of us in general.

And, all the best!!! J Give yourself a try, and you might not know some of your best efforts will be paid off. 

Crazy idea to change scientific education

Well, before you read this, I'm going to voice out a disclaimer that the content in this blog is purely based on personal opinions and reading this blog do not require any advance physics knowledge.

I know the title might sound revolutionary, but if the idea can really be implemented, we will see next generations full with great scientists around. Of course, the idea needs many manpower and strength to even start to see it happen in effect. To be frank, it is one of my aspirations to build a new technology school that can beat even MIT or Caltech in decades or centuries to come, but let's just be realistic to myself about my goals. The first goal of this idea, is therefore, to elicit a CHANGE in MALAYSIA, and particularly, scientific education in Malaysia. I believe that if the foundation of Malaysia scientific education is changed, many areas will subsequently become better. We will witness the rise of economic status in Malaysia, first or more bullet trains in Malaysia, and even Malaysia first Field Medalist or Nobel Laureate. In this blog I will address the problem up to high school students as I am still a high school student myself at the time I write this post.

Caltech, one of the world greatest institute for pure science

MIT, famed as one of the world best for its application of science in engineering and hacking

Okay, without beating around the bush, I will voice out my idea - CHANGE THE TRUE OBJECTIVE OF MALAYSIA EDUCATION, thoroughly. Yes, change is scary, but some changes can be rewarding in the end. A well known fact about Malaysia scientific education is that it is geared towards grades. But beyond grades, what else? Can the students appreciate the beauty of Archimedes's principle, for instance? Do the students feel excited about learning calculus? Do the students feel the great curiosity to explore more about DNA codes and how it really constitutes to human physical characteristics? In my perspective as a Malaysia student, a sad truth is, none of this is instilled inside students' heart. Science is fun, it is everything around us. Then, how can we be not curious about stuffs that work around us? And let's just face this fact, grades are just a number or statistics, it tells nothing about a student's personal drive, passion and perseverance towards science. It also tells nothing about how resilient a student is if he suddenly fails in his test or in his future career, for instance. I have eye-witnessed myself how some of my most sincere friends, while they are really passionate about mathematics, did not get higher marks than those who study math for exams only. And education in Malaysia regards people with higher scores as having a greater potential to excel. This is misleading. Something is fundamentally wrong. The 'something' is the objectives of scientific education in Malaysia.

The objective of scientific education should be INSPIRING AND INSTILLING THE SENSE OF CURIOSITY AND LOVE FOR SCIENCE in students. I will explain how this can be done in the some practical ways or steps. I wish to see a next generations of Malaysians, coming out to talk about applications, new inventions and new ideas about science instead of some statistics or numbers. And for me to be an agent of change, I need to voice out my opinions. Here you go:

1.) To instill a love for learning and a love for science, childhood scientific education is crucially important. If an educator fail to impress a child about how fantastic science is, the child will grow up thinking that science is boring. Therefore, START YOUNG. Instill the passion in science among children. Children's learning is well suited with colorful diagrams, sense of touch, sense of smell, sense of hearing and sense of taste. Make full use of these 5 senses in children when delivering a scientific fact. For instance, if the lesson is about manufacturing plastic, bring kids to factories and let them see and explore about how plastics are made. If a lesson on biology is about the relationship between taste and pH value of objects, let them touch and taste the objects. Fully utilize their 5 senses, and they will not have hard times swallowing facts. In fact, they will get so curious about the world around them that they come to love science. Focus on imparting interesting concepts that can be applied easily in daily life first. Build up the concepts without the need to include very complicated mathematical equations first. And it is worthwhile to spend these much of efforts to let kids love science, because, after all, kids are future leaders. The investment, though requiring huge effort, is really fruitful.

Utilize 5 senses, instill the curiosity in kids

2.) Secondly, CONTINUE THE EFFORTS IN MIDDLE OR HIGH SCHOOLS. After the students get interested in science at young age, they will move into adolescence. So, keeping up their passion and love is important, too. In middle and high schools, planners and educators play important roles. For school authorities, learn to be less curious about those statistics and start to care about student's interest and personal progress in science. For students, learn to be really curious about facts in textbooks and don't shy away from asking questions, even if they are 'stupid'. And teachers, learn to answer those 'stupid' questions, and don't rebuke students for asking 'stupid' questions. The effort is not by one party alone, but it requires a change in attitude. If the students have the curiosity in young age, with some encouragement, they will start to be brave to ask 'stupid' questions. And teachers, learn to spend time to think about how to deliver science in an interesting way. The approach will be slightly different to those intended to kids because youngsters are more prepared with some advance ideas or concepts. Youngsters also can withstand a suitable amount of 'black and white' textbook. But still, make efforts to make science appealing. Offer some demonstrations in classroom. Let the students know about reasons and applications behind a theory. Reveal the beauty of mathematical equations to students, tell them how our world is shaped through these equations. Then, the students will lose their virginity to science, and that is one of the most wonderful experiences a youngster can have in science education. And also, try to encourage and inspire instead of criticizing a student when students flunked in their tests. Imparting the optimism is important, too. And on the high school curriculum, try to focus more on problem solving than just a certain fixed facts.

It is not enough to tell students about equations. Reveal the beauty inside equations. Let them see beyond equations.

3.) Different students learn at different pace. In general, there are 3 paces of learners, slow learners, moderate learners, and fast learners. CLASSIFY STUDENTS ACCORDING TO DIFFERENT PACES AND DEVICE SUITABLE PROGRAM RESPECTIVELY.  The schools should also have a program specially targeted at specially gifted students to let them gone through accelerated learning. For the fast, gifted learners, they will feel boredom under normal school teaching pace. They are capable of absorbing facts and learn problem solving at an accelerated pace. Therefore, don't be afraid to include a university course or two in their learning. Set up few schools to accommodate the 'genius' in science by giving them rigorous science education and moderate humanities education. For moderate science learners, normal schooling pace is suffice. Malaysia schools mostly are targeted at this group of students, so moderate students should learn at this suitable pace. While for the slow learners, spend the extra efforts to develop science program to suit their pace. Most slow learners who are placed at normal schools will feel left out in the learning pace. So set up schools for these groups of people, too. Slow learners, when given appropriate education, can be successful scientist, too. And slow learner's learning need to be more personalized, so one on one is the best strategy.

4.) ENGAGE STUDENTS IN RESEARCH, FIELD TRIPS, AND OTHER SCIENCE STUFFS OUTSIDE CLASSROOM. One of the greatest misconceptions about science is that it is very academic. This, again, is another misleading concept. Science can be a hobby. There are kids who enjoy hacking. There are youths who enjoy deriving calculus in their spare time. Yes, don't mock people who enjoy science as a hobby by calling them nerds and geeks. In fact, the schools, educators and students need to be open minded about taking in science as a hobby. For university professors, start initiating research mentor program with high school students who are really serious about becoming scientists. Encourage and mentor the students throughout the process. Encourage them and push their abilities and passion in science beyond boundaries. For teachers, organize a field trip to bring the students to some of local university laboratories. Let the students see those advance equipment themselves. The schools should organize more science fairs and competitions for students to take part in. Organize innovation competitions, or give training to gifted students in school in science Olympiads competitions to give an eye opener to them about how interesting real science problem solving can be. Send students to local or overseas science summer camp program, and they will have the opportunity to meet peers of similar interest internationally. And high school students, don't be afraid to approach university professors and ask about joining them in science research. Students need to have the drive themselves, too. And students, don't feel afraid to try out crazy innovative ideas at home. By all means, let the students get involved in science outside classroom, and we will really see it ourselves the emerging of great scientists.

Summer Program, an opportunity to meet peers of similar interests around the globe.

In conclusion, change the objectives, implement the steps, and we will see a gradual (not sudden) change in nation's science standard and technology. MAKE SCIENCE INTERESTING. The efforts can reward the nation. If Malaysia implements the steps, we will see a futuristic nation full with great technology around.

And thank you if you read this blog thoroughly. Even if this blog does not change your mindset, I believe instilling a concept can spark changes in the future too.

3 Myths in Physics

The three myth of physics that constantly trigger me...

1. Stephen Hawking had once proposed chronology protection conjecture. This great physicist, having made use of Einstein's General Relativity to made postulates for Black Hole Theory, once said: If time travel is possible, where are the travelers from the future? 

So, it is known that Hawking challenged the physics community to somehow prove it both mathematically and experimentally (in an indirect approach) that laws of physics prevent time travel. But the hypothesized wormhole did not prevent time travel by mathematical calculation. 

Chronology Protection Conjecture, history must be protected!!!

2. The detection of gravitational waves. There had been thousands and thousands of experiments that directly and indirectly proved Einstein's General relativity (also known as Einstein theory of gravitation). Yet, in this theory, it predicts the existence of gravitational waves. To date, scientists had calculated the frequency of gravitational wave and it yielded 10^ -30!!! This is way too small too be detected by the built model of gravitational wave detector.

Two physicists, Russell Hulse and Joe Taylor, in 1993, had once successfully detect this extremely small frequency of wave, which gave confidence to physicists to use formula and theory of general relativity without doubt. The problem is, it is only detected ONCE (and they were offered Nobel Prize in Physics)!!! There is still no machines that can fully eliminate ground noise and other disturbance. So, the physics community are still challenged till today to build a gravitational wave detector that functions all the time.

Gravitational Waves is disturbance in spacetime, and a mean of how gravitational force is transmitted.

3. Quantum gravity. This is highly related to Einstein's childhood dream, that is to simplify the beauty of all laws of nature given by God into a single equation, perhaps not even an inch long. But, Einstein had this Theory of Everything listed as his unfinished work that had taken out his last two or three decades, he died with those papers placed messily on his table in 1955. The attempt to unify quantum mechanics and general relativity (theory of gravitational) had always resulted in failure, though tried by geniuses physicists. The significance is, if this is done, then Einstein's dream of creating Theory of Everything (TOE) that unifies all four types of major forces in universe will be finished.

It is now proposed that five versions string theory (or more) are the leading candidates of TOE. Yet, in all its splendor and beauty, it can only describes up to Tenth dimensions (the mathematics broke down at eleventh dimension). Hence, it is profoundly convincing that our world need another genius, on equal footing or surpass the supremacy of intelligence of Mr. Albert Einstein.

String theory proposes that there are more than three dimensions of space, where other dimensions are internal dimensions.

Family of Thermodynamics - Fundamental yet Impactful

So, why that old aged Mr. Thermodynamics, huh? I have been pondering about laws of thermodynamics for quite some time, at least I want to dive into both superficial and deep implications of laws of thermodynamics. Thermodynamics is all around us, from the obvious applications in car engines and refrigerators, to even the way haze spread around (haha, sorry for taking in haze example, but the widespread of haze is closely related to thermodynamics, and we shall see it later). In this blog, I will generally focus on second law of thermodynamics.

Okay, I will start off by giving a very brief definitions on the basics of thermodynamics, by expressing it in both technical wordings and layman terms. Here you go:

Technical and Formal

1.) Zeroth Law of Thermodynamics -  If two bodies are in thermal equilibrium with a third body then the first two bodies are at thermal equilibrium with each other.
2.) First Law of Thermodynamics - The total energy of an isolated system is constant despite internal changes.
3.) Second Law of Thermodynamics - Mechanical work can be derived from a body only when the body interacts with another at lower temperature; any spontaneous process will result in increase in entropy.
4.) Third Law of Thermodynamics - Entropy of a substance approaches zero as its temperature approaches absolute zero.

resources: http://wordnet.princeton.edu/

Family of Thermodynamics, in mathematical form, written by myself on my whiteboard

Layman and Informal

1.) Mr Zero - We give each other heat in equal amount, if we have equal temperature (All are equal).
2.) The No. 1 guy - Energy is a stubborn kid, prefers to always be constant in his life, although energy can change in different costumes, its attitude never change. (You can't get energy for free).
3.) 2nd Brother - Your stuff will only get messier, never tidier.
4.) 3rd Little Brother - The more you are chilled and calm, the less you want to mess around with people.

resource: myself

Mr Zero

Okay, enough of these whole bunch of definitions, we shall focus on its impact on our surroundings. Start with Mr Zero in the thermodynamics family. Mr Zero is more fundamental and obvious in our daily life experience. Imagine immersing yourself in hot, lukewarm and cold water, you can immediately tell that whether heat flows into your body, no net transfer of heat in and out of your body or heat generally flows out from your body. Its impact has been used almost in all mechanical devices, yes, Mr Zero is fundamental and impactful, and I will not elaborate too much with Mr Zero.

The No. 1 guy

No. 1 guy, sure, is stubborn. The total energy in our universe is always constant, regardless to its form. In layman words, No. 1 guy promises to change himself, but he only changes his costumes (forms) without actually changing himself (the total energy in a system). In first law of thermodynamics, the change in internal energy is often converted into net heat transfer into or out of the system and the net work done by / on (note the difference) the system. Hence, all energy is conserved. Implication and application? Yes, look at your refrigerators, car engines, air conditioner, etc. All these devices work based on The No. 1 Guy in the Thermodynamics family. In the sense of cosmology, the universe will always have the same amount of mass- energy (due to mass-energy conservation in Einstein's E = m c^2), but the universe, which is always with its constant energy available, is still vulnerable to its fate of 'death'. This 'death' concept of universe will be discussed in our dear nasty 2nd Brother. But still, I'm more interested in the 2nd brother, who is mysterious and new to many high school students or even layman readers.

The 2nd Brother

He is your messy guy, he always mess around with others. In formal words, second law of thermodynamics states that entropy (the measure of disorder) of a system will never decrease (as implied by the image I have uploaded). So, the concept of entropy can be new to many readers. Here is the thing, when you accidentally break your glass, you increase the entropy of the glass (or the glass you look messier, of course). Now, I will refer back to the spreading of haze into the second law of thermodynamics, a link of concept which might not be obvious to layman readers. Imagine gas in a container, before the cap of container is removed, all the gas molecules are kept in container, so the number of ways and free space of in which the gas molecules can move is restricted. Imagine removing the cap, or increase the space for the gas molecules to move in the piston, there will be more space available for gas molecules (and hence, more directions). Hence, the movement becomes more random (with more free space) and with the increase in randomness, the disorder of the system increases (and hence increase in entropy). Same example of observations of spreading of haze and dye is linked to 2nd law of thermodynamics, The 2nd Brother.

For a piston, an increase in space increases the direction in which gas molecules can move, and hence the movement of gas molecules become more random.

Spreading of Dye, an artsy image, it is also a phenomenon associated with concept of entropy

The 2nd Brother has another nickname, the Death God to the universe. Why such mysterious and disturbing name? Well, second law of thermodynamics is a death warranty to our dear universe. The entropy of the universe will always increase and never decrease. Observe our surroundings, apples decay, metals rust, all credit goes to our dear 2nd Brother in Thermodynamics family that only allows things to get messier (increase in entropy). Now, general readers with interest in science do know that our universe is expanding, and hence there will be more space available to the same amount of energy in the universe. This cases energy to be more disperse and spread out and hence the increase in entropy (an explanation offered earlier on how the  entropy increases when space increases). Even in charcoal, when we burn out our charcoal, the charcoal will turn into a less usable form in dust, with less useful energy available. So imagine stars in the universe being the charcoals, when stars get burnt out, its content is less usable and less heat can be obtained from aging stars that is approaching to its death. New stars will form at slower rate than old aging stars die because there will be less usable gas form available in the universe due to increase in disorder (entropy). With the expansion of universe and slower rate of formation of stars, the increase of disorder and entropy in universe sentenced death to out universe in hundreds and trillions years to come. Our universe will eventually become a cold place where the light emitted by stars will be less and less. And, hence a nasty name to 2nd brother in thermodynamics family.

3rd Little Brother

He is the little brother who looks a lot similar to 2nd brother, and 3rd law can actually be derived from 2nd law (will not elaborate the mathematical details here). His impact? This brother forbids absolute zero temperature (together with second brother). Why? Combining 3rd law and 2nd, you shall see that entropy (disorder) can never decrease and hence the temperature can never get down to absolute zero. In absolute zero temperature, all kinetic energy will be abstracted out of a system, and hence you make something in total stillness. This can't happen, it is forbidden by our Mr. Uncertainty (Heisenberg Uncertainty Principle). In formal words, Heisenberg Uncertainty Principle states that you can never know position and momentum of a particle at the same time. There is always uncertainty about the positions of molecules. Hence, by lowering a molecule's temperature to absolute zero, you are making it in total stillness and you can determine with certainty on where the molecules is and its momentum (momentum being zero). This is forbidden in quantum mechanics, a family of laws in physics.  

The Conclusion

In all our families of thermodynamics, we see that these laws affect us in both macroscopic and microscopic scale, ranging from simple daily life observation with spreading of dye to the death of universe. Physics, in all its implications, is beautiful. I have to admit that The Family of Thermodynamics, after all, is really fundamental and impactful. Hope you enjoy reading and have a nice day ahead.

How Observations in Astrophysics are done, and some unexpected discoveries that follow

Hello world, I have been inactive on blogging for a while due to external examinations going on. However, while I was preparing for my exams, I have thought of some astrophysics ideas to be shared on my blog right after exams. Okay, let's start with some 'flashback' of what have been done in astrophysical researches in past century.

One of the most interesting feature in astrophysical observations is that we make a lot of deduction and extract a lot of information, based on one thing, light itself (in more technical term, electromagnetic wave). I will discuss a few aspects and on how so many information can be extracted, purely based on light itself, and on some examples of past historical amazing discoveries that follows.

Before I proceed to astronomical observations and applications of light, I will bring in some intro of bizarre features exhibited by light, an amazing phenomena in many aspects. In 1900s, physicists discovered a very weird property of matters that emits light. When hot matter is heated up to a very high temperature, it glows. The hotter it is, the brighter it glows. But one of the weird features was that, when the object is heated, it gives out a discrete pattern of different colors of light instead of just a spectrum of continuous rainbow lights. It is as if the colors, frequency and wavelength of lights are quantized (can only have certain fixed value, for example, think of Malaysian currency, we can only have 5 cents, 10 cents, 20 cents and so on. We pay in terms of 5 cents as smallest currency instead of 1 cent). And for a matter to emit light, these must be a transition of energy level of electron from higher energy level to lower ones, and only fixed wavelength (and color) of lights emit will imply that electron can be at certain fixed position only.

Quantization, as the diagram implied, is just like a staircase. In our daily life, the concept of quantization is best to be think of as currency note.

Transition of electron from higher energy level to lower ones will emit light, the mystery of emission of light hence is due to electrons 'jumping' to lower level, and since electron can only be at certain level of energy, only certain colors of wavelength is observed.

So why do I explicitly elaborate on property of emission of light on quantum mechanics aspect? Well, discovery of helium comes from this property of physical law. Remember helium,  the element you often see in your high school periodic table (for those who take chemistry)? Helium is extremely rare on earth and only exist in trace amount (can hardly be detected). In 1968, researchers' pursue for discovery of helium is finally accomplished when astrophysicist made an observation of light emitted by sun during solar eclipse. The first discovery of helium, which subsequently lead to the use of helium in balloons, is done through astrophysics! Helium is discovered through emission of light (that certain object will glow and give specific wavelength), though this first discovery has been an indirect observation.

But astrophysical observations through light is not only used to detect undiscovered elements in periodic table alone! There are many more information that we can extract, purely just based on light. I will feature 2 more examples in this post. Another information we can get (other than elements present in certain planets ) is on temperature range of the planet. This is a direct implication from a physical law, Wien's Law, which states that wavelength of light emitted from glowing object is inversely proportional to temperature of glowing object. This means that the greater the wavelength, the lower the temperature, and this actually explains one of the high school students' myth (the fact that redder sun is colder and blue stars are hotter). From the color (and hence the wavelength of light) itself, we can make startlingly accurate prediction of temperature range of a certain stars, and this, is another amazing application of light.

Wien's Law, to show the inversely proportional relationship between wavelength of light and temperature of glowing
object.

The last application of property of light in astrophysics will be on a phenomena called 'gravitational red shift'. This phenomena is based on 2 important laws, 1.) light is electromagnetic wave 2.) Doppler's effect, when there is relative motion between observer and source of wave, there will be apparent change in frequency. I know the definitions of Doppler effect will sound daunting to many tenth graders, so I will offer a simplified explanation of it. Imagine a lorry sounding a horn as it is approaching you and leaving you, when it is approaching you, you will find that the tone of horn will get higher as it is approaching you and tone of horn getting lower as it is leaving you. This is one of the most common Doppler Effect phenomena in daily life (on the apparent change in frequency of wave), and the same property goes to light, an electromagnetic wave. In astronomical observations, there is apparent red shift of light (that the wavelength of observed light emitted from stars), the light gets redder (and hence the increasing wavelength, and the frequency of light gets lower) and as the frequency of emitted light from stars decreases, this implies that the stars observed is leaving and distance itself from mother earth (just like the lorry example). And actually, the expansion of universe is based on gravitational red shift! Again, amazing discoveries that are beautifully linked to each other.

If you don't understand Doppler Effect, imagine a lorry sounding horn as it is coming to you.

I'm only able to post 3 beautiful applications of observation of light in astrophysics. There are more, for sure! And I hope you enjoy reading the tidbits of astrophysics.