If you enjoy A-Level Physics, you might be considering a Physics degree, and perhaps even an Oxford Physics degree. But there is a significant difference between A-Level and university; subjects can change in that gap. Does Physics? Read on, and find out.
How does university physics compare to A-Level physics?
Lots of the physics you study at university develops some of the key concepts you are exposed to at A-Level. For example, you will study circuits, electromagnetism and optics in great depth, all topics you have previously been exposed to at A-Level standard. However, the crucial difference at university-level is the depth with which you are expected to understand them. You are expected to peel away any pre-existing conceptions and rebuild your knowledge of the science from its mathematical foundations.
Not only will you learn how a system works, and how to apply an equation in a situation, but why you are doing so, and how these equations and concepts are originally derived. You will come to understand concepts that you previously just memorised, and Physics thus requires a vast array of mathematical skills that you may not have realised at school-level.
To give you a taste of Physics at University, and how it compares and differs to A-Level study, here is a breakdown of the first-year Oxford Physics syllabus.
This builds upon the Newtonian mechanics you have studied at school, but goes into more depth concerning the derivation of the equations and their wider repercussions.
In this course you will focus on the study of Newton’s Laws of Motion and the content that follows from that. This includes collisions, orbits, and the ideas of rotational mechanics versus translational mechanics. You will study further conservation laws, including conservation of angular momentum.
Lots of the physics you study in this course has familiar roots, grounded in A-Level Physics, although you will be expected to analyse and manipulate situations using more complicated mathematics than you are used to. For example, the equations of motion you are used to using in Cartesian coordinates you will also be expected to manipulate in Polar coordinates.
If you haven’t studied Further Mathematics A-Level, it is definitely worth looking over this content before you start studying physics at University. Although there will be introductory courses that cover this content, so that everybody’s maths is at the same stage, these go very quickly, so some independent study is required to fully understand the advanced A-Level maths. For example, an understanding of polar coordinates and hyperbolic curves is essential to the study of this classical mechanics module.
An example of a question on this topic would be:
Prove that if a particle of mass M moving with non-relativistic speed v collides head on and perfectly elastically with an identical particle at rest, the first particle comes to rest, and the second acquires speed v.
As you can see, this builds upon the collisions studied at A-Level, although you are now expected to prove this, so derive it from its foundations. Also, you have to understand how all the assumptions (such as ‘perfectly elastic’ and ‘head on’) contribute to the desired result.
The skills are similar to those required for A-Level, but you must be more specific and precise, and understand how everything is working within the system.
This is the study of electric forces and magnetic forces, touched upon in most A-Level syllabuses, but taught and explored from the foundations at university level.
In this course you will explore how electromagnetism works, and learn and understand a variety of new laws, such as Gauss’ Law, Ampere’s Law, and the Biot-Savart Law. You will be expected to apply vector operator identities and vector analysis to electromagnetic questions, as well as being able to manipulate equations about charged particles. You will also study electromagnetic induction in greater depth, and how it affects the energy of particles.
Gauss’ Law: The total of the electric flux out of a closed surface is equal to the charge enclosed divided by the permittivity.
Many of the concepts here may seem familiar, but this law also introduces new concepts, such as permittivity (a constant of proportionality that exists between electric displacement and electric field intensity), and a new relation between the factors. This law can also be employed and manipulated in an integral form, so integration becomes a key technique in this field.
Ampere’s Law: For any closed loop path, the sum of the length elements times the magnetic field in the direction of the length element is equal to the permeability times the electric current enclosed in the loop.
Permeability is a measure of the ability of a material to support the formation of a magnetic field within itself, and is another new concept introduced at university-level physics.
Biot-Savart Law: an equation that describes the magnetic field created by a current-carrying wire, and allows you to calculate its strength at various points.
This is a new topic explored at university, and is crucial to the later study of general relativity within the Physics course.
In special relativity you study the core physical effects that we get when particles move at speeds close to the speed of light, whilst holding the speed of light as a constant. You learn to draw space-time diagrams (an example shown below) that show how objects can appear to be moving at different speeds when measured by different observers.
This leads to some astounding results, including time dilation (where one person in one place can age more than another in a different frame) and length dilation (for example, to an observer, a pole of a greater length than a barn can fit entirely within a barn). You will study how to calculate the discrepancies in speeds when observed by different observers, using Lorentz transformations, which you will also learn to apply to dynamics and kinematics.
If you are interested in exploring special relativity before coming to university, you could investigate the Alice and Bob paradox, or the barn paradox.
This is an example of what a space-time diagram looks like:
In circuit theory at university-level you build upon many of the concepts you learn at A-Level, such as resistance, capacitance and inductance, but apply further mathematical techniques to understand their function.
You will study the use of summation, integration and differentiation in investigating circuits, and also the growth and decay of currents in circuits, and how the time constant is derived and operates. The circuit representations you learnt at A-Levels will be used in circuit theory at university, so make sure you are familiar with the content of your A-Level Physics before attempting university circuit theory! It also introduces you to key concepts such as impedance and complex impedance (which is essentially the effective resistance dependent on other factors in the circuit.)
“Circuit theory is one of the first times you will see imaginary numbers, introduced as obscure and strange in Maths A-Level, applied directly to Physics.”Jake J., Physics, Oxford
Waves and Optics
Optics is integral to some A-Level syllabuses whilst absent in others. It addresses the basic properties of how light behaves, and will be built up from a foundational level at university, due to the disparity in students’ previous knowledge.
In your first year optics course you will look at familiar properties such as reflection, refraction and diffraction. You will also look at the effects of light beginning to display wave-like properties. This is a more knowledge-based course, and although it may not introduce any more theory than is included in some A-level courses, it does introduce more content.
For example, you go into more detail about converging and diverging lenses, and how lenses are used in telescopes, and in medical devices. You will also study the mathematics behind optics.
In your first-year of optics you will only study geometric optics – that is, treating light as straight lines and using mirrors, lenses etc. In your second year you will also study wave optics, where you will now treat light as an actual propagating electromagnetic wave which can diffract and interfere.
An example of a question from this course would be:
Describe the conditions necessary to observe optical interference fringes in a Young’s slits experiment.
Maths (split into two exams)
Maths forms a hugely important part of physics at university, due to the depth of understanding required. In your first year you will be exposed to a large amount of maths, and sit two mathematical methods exams, which explore the content covered. Although lots of it will be developed from A-level content, you will also be introduced to entirely new fields of mathematics, and their applications to physics.
This includes content like:
- Differential equations, first and second order, and their application to forced vibrations of mechanical or electrical resonant systems
- Complex numbers (including argand diagrams and De Moivre’s Theorem)
- Vector algebra, and applying these skills to classical mechanics
- Eigenvalues and eigenvectors, and matrix diagonalisation.
“The notion of vector spaces and linear algebra can seem very abstract at first but is so so useful for quantum mechanics which is a big part of second year.”Jake J, Physics, Oxford
This includes content like:
- Elementary ideas of sequences, series, limits and convergences
- Differentiation techniques, including partial differentiation and Taylor expansions to explore maxima minima and saddle points
- Double integrals and their evaluation by repeated integration in Cartesian, plane polar and other specified coordinate systems
- Transformations of systems using Jacobians
- Basic Probability theory
- Derivation of the one-dimensional wave equation and its application to transverse waves on a stretched string, and D’Alembert’s solution, and solving wave equations of first order using separation of variables.
Every week you will spend about 6-8 hours in the lab, and are expected to complete certain projects that contribute to your mark at the end of your first year. You will then have to evaluate and understand your results, and use statistical analysis to present them.
You do labs in all four of the main sections covered in first year, and some examples of the labs you do in each section are:
- E.g. Excitation of circuits by step emfs:
This experiment compares measurements and models of real circuits (called equivalent circuits) when they are excited by emfs which step abruptly from one steady value to another
- General Physics
- E.g. Radioactivity and statistics:
The first part uses the random nature of the radioactive decay in the study of probability distributions. The second part of the experiment is on the properties of alpha, beta and gamma radioactivity.
- E.g. Grating monochromator:
Spectral lines of mercury are used to obtain an accurate calibration. The Balmer lines of atomic hydrogen are investigated, and the Rydberg constant obtained.
- Electrostatics and Magnetism
- E.g. Self and mutual inductance and Faraday’s Law of Induction:
Here you will explore the self-inductor as a circuit element. Air-filled coils are used as well as ferrite core inductors. The relation between self and mutual inductance is explored. A quantitative check of Faraday’s law of induction is made.
Computer labs form a major part of the practical course in first year:
- No previous computing experience is required for this course.
- You will learn to use the MATLAB language.
- The computing projects count for 2 days’ lab credit. You have 17 days worth of labs, and you need 12 days worth of lab credit in total to pass the year.
- The computing labs are so important because you will use the skills you learn in MATLAB when doing data analysis in the main practical labs.
These modules are the core of first-year physics at university, but you also get the opportunity to study short options, including complex variables, astrophysics, and quantum ideas. As the course progresses it becomes more diverse, with further options, but your degree will be fairly structured throughout.
As you can see, the course builds upon pre-existing knowledge, but reworks the way in which you study physics, focusing on derivations and mathematics, not just the accumulation of knowledge and facts.