At O level students have the option to take Pure Science (Choosing 2 from Physics, Chemistry or Biology) or Combined Science (Choosing between the combination of Physics and Chemistry or the combination of Biology and Chemistry). Pure Science covers a wider range of topics and offers a more in-depth exploration of the concepts in each subject area. Conversely, combined science teaches several key components of Biology, Chemistry and/or Physics (in pairs of Physics & Chemistry or Biology & Chemistry) and is counted as a single subject.
For information on the exact difference between combined science and pure science, you may download the Syllabus documents from the SEAB link below. Take note that you need to look at the syllabuses examined from 2024 as this year is the start of the new upper secondary Science Syllabuses.
A. Knowledge and Skills
While Combined Science pairings cover about 75% of the Pure Science subjects, they are assessed as a pair. So while there is less to cover, taking combined science means that you have to do well in both subjects in the pair. Pure science is a good choice if you have a particularly high ability in one of the sciences.
B. Entrance in Junior College (JC)
Pure Science is useful if you want to take 2 science subjects in Junior College.
In JC, if you want to take the science stream subjects, some JCs do not allow you to take 2 science subjects if you don't have the relevant pure science subjects taken at the O Levels. All Polytechnic courses only require Combined Science as a minimum requirement for the science based diplomas.
DO NOT CHOOSE PURE SCIENCE TO AVOID COURSE WORK!
Some students choose Pure Science as a way of avoiding subjects that have a coursework requirement. This is a highly discouraged as this often leads to students taking on a subject that is not actually a subject of interest. Given the intensity of the Pure Science Syllabuses, this lack of interest will mean that it will hard to motivate themselves to do well in the O Levels.