Part IA and IB Physical Natural Sciences

by Charlie Bridge

Part IA

Part IA Natural Sciences has a reputation for being one of the toughest first year courses in the world, because it is. It contains effectively three and a half times the volume of a normal first year course at other universities and so time management is perhaps the most valuable tool for a Part IA natural scientist. Part IB is equally extensive and noticeably more difficult. Luckily the style of teaching is virtually identical in both years – achieving well in the first year bodes well for the second. In my experience, there is no effective short-cut to achieving in the Physical Natural Sciences – it takes time.

In contrast to the Biological Sciences the Physical Sciences has a very clear, structured and closed syllabus. Understanding the syllabus is essential to being able to perform well in the exams – there are few surprises in the Tripos papers.
Part IA Structure

Within the “pure” Physical Sciences there is a limited choice of courses. Everyone does some form of Maths. I recommend that anyone starting Part IA begin the year with the Mathematics B option. It is always possible to drop down to the A option later in the year and the additional Mathematics is very useful in later years. The remaining courses are fairly straightforward: most students should cope with their complexity. The difficulty arises with managing four different workloads. Completing supervision work as soon as possible is a healthy way to spend your Cambridge career. It is possible to juggle a variety of other commitments such as sport, drama or music if you are an efficient worker. If you are not then you will have to compromise to obtain high marks in the exams. Keep an up-to-date calendar that includes deadlines to stay on top of the work – you will never have nothing to do.

Part IB

Slightly more focussed than Part IA but still broad, there is an obvious choice of courses in Part IB if you know what you want to do in part II. Taking Maths is essential for Physicists and recommended for Chemistry students. The Materials course blends well with all others in the Physical Sciences allowing you to choose according to preference or to assist with future Materials interests. Taking one part of any of the two-part courses is only recommended if that course is not your preferred Part II choice or if you intend on taking the Half-Subject Physical Sciences course in Part II (although that course is not recommended). There are exceptions. Notably, taking Chemistry B without Chemistry A confers little, if any, disadvantage, although there are some restrictions on subject choice in Part II. Often, students taking a third course that is completely different from their other two, or even from the Biological Sciences, find the difference makes it more difficult to keep track of all their courses at once. Do not spread yourself too thinly in an attempt to keep your options open, balance the two. Taking Mathematics with both Physics options, for example, leaves almost no choice in Part II but there is considerable overlap between the courses and they are very complementary.

A proficiency in mathematics greatly facilitates the study of all the courses in the Physical Sciences. Simply being swift and reliable at algebraic manipulation will save a great deal of time throughout the year and, crucially, in the exams. If you are not a competent mathematician, seriously consider devoting extra time to improving your maths or specialising in a less mathematics intensive course, such as the Earth Sciences.

Lectures and Notes

The lecture notes are a sufficient resource for achieving very high marks in the exam papers. The lecturers are closely involved with the writing and marking the Tripos papers. Attending all the lectures is the simplest way to absorb all of the information required to do the example sheets. With the courses being so different, especially in Part IA, it is not easy to teach yourself.
The notes provided as part of the course are mostly of very high quality and almost all lecturers supplement them with additional notes making lecture attendance even more important. It is often made clear what the lecturer feels is a more important part of the course during lectures, allowing for targeted revision.

Additional books can be helpful but changes in notation can cause confusion and it often takes a great deal of time to find relevant passages. Lecturers will recommend books that are appropriate for the course and some imply that reading these books is vital. I recommend following a book for whole chapters or sections properly or ignoring them completely. The Tripos examinations will use the same notation used in the notes and some problems closely resemble ones brought up in the lectures.

Examples sheets

If you have attended every lecture and completed every examples sheet then you should find yourself in a very good position to revise for the examinations. I cannot emphasise enough the importance of these examples as they are the only way to efficiently memorise the material in the courses. They also provide an extremely useful revision tool.

The easiest way to complete these sets of problems is in tandem with the lectures. Do not let the fact that your supervisions are behind schedule delay tackling the problems relevant to the lectures you are currently attending. The examples sheets are designed to lead up to Tripos questions and your exams will almost certainly contain questions that are very similar to those completed during the year, some may even be identical in places. If you cannot complete the examples sheets, you will not be able to score highly in the exams.


Supervisions are the best way to cement understanding and iron out any issues you may have with the examples sheets. Make full use of the supervisors, who are usually very competent. Turn up on time with the questions you wish to ask already in your mind. Do not let slower fellow supervisees hold up the supervision – use them as practice by trying to answer their questions ahead of the supervisor if you can. If you can teach someone how to answer a problem then you have fully understood it. Equally, do not let fellow students rush over important points or skip questions you do not understand. Supervisions are short and important, do not waste them.


These do not count for a large proportion of marks in Part IA and IB, so do not devote an inordinate amount of time to perfecting the write-ups. Completing them all is still necessary, as having a solid base of marks on starting the exam period is comforting. They can assist with understanding but I advise that little time should be spent on problems that arise during experiments as they are not worth the time taken to solve, especially in physics where the experiments often use theory beyond the scope of the course.

Past Papers

A student who has not completed a great many past papers questions will probably not do well in their exams. These are easily available online and should be started as early as possible as completing a decent number of questions from past papers from all four (Part IA) or three (Part IB) of your courses takes a lot of time. Do not waste time with questions that are no longer relevant to the syllabus – this becomes common with older papers.


There is no substitute for spending time in order to achieve high grades in Natural Sciences. This time is best spent evenly spread during the year, as it allows for more efficient revision and a more relaxed Easter term. There are students who can get away with very little work and do well. They are the minority and it is likely that you are not one of them if you are reading this. Keeping all of your notes and example sheet answers (neatly written up) in order is essential. The first two years of Natural Sciences are compatible with an active social life, despite what you may think, if you organise your time effectively.