IB Physics Options

Hi! I am Saad. I am a Mathematical Physicist and a Mathematics and Physics tutor at The Edge Learning Center. I thoroughly enjoy researching and teaching Mathematics and Physics.

Over the years, I have often seen pupils concerned about selecting the appropriate options for their IB exams since (for obvious reasons) they tend to have very little knowledge of the demands of each option before actually working through the relevant course material. Therefore I have prepared a brief survey of the options in the IB Physics curriculum to enable pupils to make an informed decision.

The IB Physics curriculum requires students to select one option out of the four currently available to them. Each option is then further split into Core and Higher Level topics. Often students have difficulty in selecting an option, since they tend to lack the information required to make an informed decision. In what follows, we’ll review the fundamentals of each of the four options:

A. Relativity

This option explores Einstein’s theory of relativity, with a focus on Special Relativity

EinsteinThe Core section largely deals with the kinematic aspects of relativity. The Birth of special relativity resulted from Einstein’s exploration of the incompatibility between Maxwell’s Equations of Electromagnetism and the Galilean/Newtonian picture of spacetime. Insisting upon the speed of light as an invariant quantity, Einstein went on to establish his laws of relativity. Since Einstein’s theory insists upon the equal-footedness of all frames, in order to change perspectives (i.e. reference frames) we must use Lorentz Transformations which are essentially equations relating the spacetime coordinates of one observer’s reference frame to those of another observer’s reference frame. To better understand spacetime transformations, we are led to Spacetime Diagrams that geometrise the relationship between the coordinates of different observers’ reference frames.


Space TimeThe Higher Level section largely deals with the dynamical aspects of relativity. Relativistic Mechanics explores the consequences of Einsteinian relativity for a particle’s energy, momentum, and acceleration and applies the results of those consequences to understand relativistic processes, e.g. high energy particle decays and collisions. Finally, we explore General Relativity wherein we understand how the curvature of spacetime affects the dynamics of particles within that spacetime.

If you want to know why E2 =p2c2+m2c4, then you should pick this option!

B. Engineering Physics

This option largely further explores Mechanics and Thermodynamics with a view to analysing the properties of more realistic physical systems of practical importance. 

RotationThe Core section initially explores the mechanics (i.e. kinematics and dynamics) of Rigid Bodies. Whereas in the Mechanics core students mostly work on point particles, in this section they explore the mechanics of more realistic extended rigid bodies (e.g. rulers, wheels, etc) in which all constituent parts may not exhibit the same motion. Since rigid bodies have the possibility to rotate about given axes, an understanding and analysis of Rotational Dynamics is also required. The second Core topic of this section is Thermodynamics, which is the study of the bulk properties of physical systems without regard for details at the short length-scale. Temperature is a physical property that is only sensible for an ensemble of particles.

Jet planeThe Higher Level section initially explores the properties of Fluids and Fluid DynamicsThe ability of fluids to flow distinguishes them in from solids and grants them unique properties, e.g. viscosity. Moreover, students will analyse the bulk movement of fluids, in particular laminar flow and turbulent flow. The second topic deals with Forced Vibrations and Resonance. The students investigate the interaction of oscillating systems with external forces (e.g. friction) and analyse their effects on the properties of the system, such as the amplitude, energy, etc.  

If you want to know what it takes to engineer the greatest jet planes and the fastest hypercars, then you should pick this option!

C. Imaging

This option explores various aspects of how electromagnetic radiation can be used to probe and study physical systems and to better understand our universe.

telescopesThe Core section initially explores the Fundamentals of Imaging such as image formation with lenses and mirrors and the properties of those images such as magnification and aberrations. The focus is on geometric optics whereby ray diagrams are employed as the main tool for understanding the formation and manipulation of images. This knowledge is subsequently used to understand the design and functioning of Imaging Instrumentation such as microscopes and telescopes. Furthermore, the fundamentals of imaging are employed in the analysis of Fiber Optics, especially their use in information transmission.

The Higher Level section is focussed on Medical Imaging, in particular X-Ray, Ultrasound, MRI, and NMR imaging techniques. The section requires students to develop an understanding of how the different techniques are used to produce images and the pros and cons of each technique.

If you want to know how physicists explore the breadth of the universe, what really enables cloud services to work, and how MRI scans are used for diagnosing various illnesses, then you should pick this option!


D. Astrophysics

This option is a survey of astrophysics. It explores the various important areas of research in astrophysics and several of the important solved and unsolved problems within each area.


The Core introduces the fundamentals of astrophysics. Stellar Quantities employed in measuring distances to and characteristics (e.g. luminosity, apparent brightness, etc.) of astrophysical objects are introduced and defined. The stellar quantities are then used to explore and understand Stellar Characteristics and Stellar Evolution. This involves an analysis of the properties of stars and their classification based on these properties. Remarkable insights and patterns image from this simple classification scheme. Finally, the Core explores the evolution of the universe as a whole in terms of its Cosmology. The beginnings of the universe and the Big Bang Hypothesis as a leading hypothesis explaining the likely origins of the universe are discussed in the context of evidence from the Cosmic Microwave Background (CMB) and Cosmological Red Shift data.

big bang expansion

The Higher Level section essentially explores detailed aspects of topics explored in the Core. It analyses Stellar Processes with a focus on the Jeans Criterion for star formation and the process of Nucleosynthesis which is responsible for the creation of the variety of atomic elements. Further Cosmology discusses and analyses several outstanding and vital questions in modern Cosmology. These include the problems of the nature and origins of dark matter and dark energy. Only around 4.6% of the matter-energy content of the universe consists of atomic matter. The remainder is made up of dark matter and dark energy. They are called dark as they are not detectable using conventional optical and radio astronomy. 

If you want to learn about the most exciting frontier in modern physics, explore some of the toughest outstanding questions puzzling physicists today, and  get a head start on exploring some of the deepest mysteries of the universe, then you should pick this option!

All the options are extremely exciting and offer ample opportunities for students to satisfy their curiosities. In an ideal world, students would perhaps study and explore each of the four options. Each option requires students to demonstrate a wide variety of analytical skills. Ultimately students should decide which option to select once they have completed the essential elements of the IB Physics course. Having taken the aforementioned overview into consideration in light of their preferences, the students should be able to make an informed decision with respect to selecting an appropriate and academically fruitful option!

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