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Part IA - Examinations

The Natural Sciences Tripos exam for IA Earth Sciences consists of two papers.  These are taken in the main examination period, during the second half of the Easter Term (although some colleges may set exams at other times).

Theory paper: The theory paper is three hours long and divided into two sections. Section A will be a single compulsory calculation question, typically involving numerical or graphical analysis of data or concepts. From section B you will be asked to answer four questions chosen from eight or nine offered. You can expect about two questions for each half-term of the lecture course, although there may be questions covering different parts of the course. Calculation components to these questions are not precluded.  60% of the marks are allocated to the theory paper.

Practical paper: The practical paper is three hours long and comprises four compulsory questions taking three quarters of an hour each:
Q1 - Identification of 15 hand specimens of rocks, minerals, fossils or of photographs of geological features.
Q2 - Microscopic description and identification of rocks.
Q3 - Description, identification and interpretation of fossil material.
Q4 - Interpretation of a geological map.
40% of the total Earth Sciences marks are allocated to the practical paper.

You can take an approved NST calculator plus appropriate writing and drawing equipment into the examination. You cannot take in any reference material, although a reference booklet is provided for Q2 of the practical exam.

Although there is no continuous assessment, the high proportion of marks attached to the practical exam means that you need to attend and make the most of the practical classes that we offer. It is difficult to get a good grade overall without doing well in the practical.

Earth Sciences is one of the subjects in IA NST that requires you to write ‘essay-style’ answers for the theory paper. Guidelines on what is expected are provided in Appendix III to this booklet ‘Writing answers to Earth Sciences questions in supervisions and exams’. A guide to how marks are allocated is included as Appendix IV.

The IA Earth Sciences marking is done by a panel of four examiners, not necessarily staff who have taught the course in that year. Given the 60%/40% ratio of theory to practical marks, each theory question is effectively scored out of 12% and each section of the practical exam out of 10% of the total marks. No marks are awarded for missed questions. The raw total mark out of 100% is used to rank candidates by order-of-merit. The raw marks are then scaled (‘norm-referenced’) such that approximately 25% of candidates get a First Class (scaled mark ≥70), 65% get a Second (≥50) and 10% get a Third (≥40) or Fail (<40). The overall mark in IA NST is totaled using these norm-referenced unrounded subject marks, ensuring comparability between different subject combinations. Your College Director of Studies receives a breakdown of your marks into a theory and practical score for each subject.