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.