‘Combined Sciences’ or ‘Pure Sciences’?

At the end of Secondary 2, students are required to make a decision on their subject combinations for Upper Secondary.These will also be the subjects that they will be taking for their Singapore-Cambridge GCE ‘O’ Level. Students then need to decide whether they want to take ‘Pure Sciences’ or ‘Combined Sciences’, and this is a dilemma for many students. Even if students decided to take ‘Pure Science’, another question will be whether to take ‘Double Sciences’ or ‘Triple Sciences’.

We encourages students to choose ‘Pure Sciences’, if they are eligible to choose this pathway. Criteria differs in different schools, but schools are usually looking at Overall Grade and grades for Science and Mathematics. Taking ‘Pure Sciences’ will put a student in advantage if he/she want to pursue GCE ‘A’ Level (Science Course) or Science-related courses in the various Polytechnics in Singapore, after their GCE ‘O’ Level. However, at the end of Secondary 3, if students showed that they cannot cope with ‘Pure Sciences’, they will be given a choice to change their subject to ‘Combined Sciences’.

So, the question now is, what are the differences between ‘Pure Sciences’ and ‘Combined Sciences’? In terms of content coverage, ‘Pure Sciences’ will cover approximately 20% more content than ‘Combined Sciences’. For example, for Chemistry, ‘Pure Chemistry’ covers topics like Electrochemistry and Ammonia, which are not covered in ‘Combined Chemistry’. You may refer to the respective pages (under Division of Sciences) to see the differences between the syllabi. Questions in ‘Pure Sciences’ may not be as direct as those of ‘Combined Sciences’. ‘Pure Sciences’ emphasise on Data Reading & Analysis as well as Application of Concepts.

As Sciences are experimental by nature, students also need to undertake practical as part of their examination. For ‘Pure Sciences’, students will take three separate assessments during curriculum periods (known as School-based Science Practical Assessment, or SPA), whereas for ‘Combined Sciences’, students will take only one assessment (also known as Paper 5), usually during mid-October. For ‘Pure Sciences’, students are graded based on their experimental techniques and their answer scripts, whereas for ‘Combined Sciences’, students are graded solely based on their answer scripts (however, students may also be penalised if they request for assistance etc.).

Next, the grade for ‘Combined Sciences’ is obtained from the two Sciences subjects, whereas the grade for ‘Pure Sciences’ is of one subject only. For example, a student who scored A1 for one subject and C6 for another will probably scored a B grade if he/she takes ‘Combined Sciences’, but his/her grade will be two separate ones (i.e. A1 and C6) if he/she opted to take ‘Pure Sciences’. Further more, the ‘C6’ most likely not be used in the computation of aggregate scores, for admission into Junior Colleges / Polytechnics.

Then, the next question, ‘Double Sciences’ or ‘Triple Sciences’? Students are only advised to take ‘Triple Sciences’ if they obtained a very good grade (preferably 85% or above) for their Lower Secondary Sciences. If not, students are advised to take ‘Double Sciences’. There are some schools in Singapore that apparently stopped offering the ‘Triple Sciences’ combination, in which students need to take ‘Double Sciences’. This may be probably due to the objective of the school to develop students to be ‘all-rounded’, so schools would like to offer subjects of all fields (e.g. language & linguistic, humanities), so as to broaden the horizon of students.

These are the common MYTHS that students have on the different Sciences subjects.

  • ‘Pure Sciences’ are extremely tough.

‘Pure Sciences’ is actually not very difficult, especially for students with passion.

  • ‘Combined Sciences’ are for Lower Ability Learners.

‘Combined Sciences’ are offered to students who are not very strong in science, but these students may had done very well in other subjects, like literature, which are not related to Science. Students taking ‘Combined Sciences’ can also do very well for their examinations.

For Secondary 2 students, make a wise choice. For Secondary 3 students taking ‘Pure Sciences’, whether to change your subject to ‘Combined Sciences’ do not depends entirely on your Secondary 3 result. Change your subject combination only if you are not confident. There are students who failed their ‘Pure Science’ in Secondary 3, and obtained a merit for their GCE ‘O’ Levels.

For queries or feedbacks, please email us at horizoneduc@gmail.com.

The reason for the use of quotation marks is that the terms quoted are not the official terms. ‘Pure Sciences’ is known as Science with SPA whereas ‘Combined Sciences’ is known as Science.


BIOLOGY – Movement of Substances

The topic Movement of Substances is likely to be covered in Secondary 3. Students will need to know what is meant by the terms diffusion, osmosis and active transport. In addition, students also need to know the application of these processes.

Diffusion is the movement of substance from a region of higher concentration to a region of lower concentration, down the concentration gradient. Another process, osmosis, is also similar, with the exception of three differences

  • it is the movement of water, not substances
  • from a region of higher water potential to that of lower water potential (not concentration)
  • through a partially-permeable membrane.

Take note that diffusion and osmosis do not need energy (hence known as passive transport), but active transport requires energy. Active transport is the movement of substances from a region of lower concentration to a region of higher concentration, against the concentration gradient.

Students may find this easy, and it will be a bonus if this question come out, as a definition question, in Free Response Question. If question of this topic really come out, do expect some applications that you may not have seen in your textbook (e.g. transdermal patch).

Try this question: Describe what will happen to a red blood cell when it is placed in a beaker of (a) distilled water; (b) 50% glucose solution.

Do email us your answer to this question to horizoneduc@gmail.com and we will provide comments for your answer.

We hope that you will find this post useful. For any questions / feedback, please email to horizoneduc@gmail.com and we will respond to your email as soon as possible.

Release of GCE ‘O’ Level Time-table 2015

Secondary 4 Express and Secondary 5 Normal (Academic) students in Singapore are currently in their preparation for the National Examination, Singapore-Cambridge GCE ‘O’ Level. The Singapore Examination and Assessment Board (SEAB) had released the time-table for the National Examinations a few weeks ago.

There is no need for students to print out or study the time-table, but it will be good for students to look at the time-table released first. Later in the year, eligible candidates will be given an entry proof, which will contain the individualised time-table. However, it is unlikely that the entry proofs will be ready before the mid-year Mother Tongue Written Papers.

As of the time of publication of this post, the date for Mother Tongue Papers will be 2 June 2015 (Tuesday), whereas for Mother Tongue B will be a day after. Candidates might like to take note that the Mother Tongue Written Papers are in less than 3 months. Mother Tongue is ‘special’, as candidates have the choice to ‘re-take’ the written papers (Paper 1 and Paper 2)  in end-year in the situation when they are not satisfied with their results. However, it is advisable for students to do well for the mid-year Papers, so that they can utilise more time in the second semester to prepare for other subjects, specifically humanities, mathematics & sciences as well as other subjects.

Horizon Education will be constantly providing assistance to students. Should you need any academic advise on the subjects that we covered, do email us at horizoneduc@gmail.com. We will also be uploading more resources for students to refer to. Horizon Education wishes all the best for candidates taking GCE ‘O’ Level Examinations.

CHEMISTRY – The Periodic Table

The periodic table is provided for Singapore-Cambridge GCE ‘O’ Level Examination, but there is this topic in the syllabus that covers the ‘chemistry’ of the periodic table, specifically

  • Group I elements (alkali metals)
  • Transition Metals
  • Group VII elements (halogens)
  • Group 0 elements (noble gases)

All the different classes of elements have different properties, which students must be familiarised. Special care need to be taken that the noble gases are inert, and explain why it is inert, with the application of the idea of atoms achieving stability.

More resources on this topic will be released soon.

CHEMISTRY – Reactions of acids

Acid is a form of chemical, that dissociates to give hydrogen ions in aqueous solution. There are some chemical reactions related to acid that students need to know, and hence apply them. Note should be taken that these equations are very important for the topic, salt, which involves the preparation of salts.

Acids react with metals to produce salt and hydrogen gas.

  • Take note that the metal need to be reactive. However, metals that are too reactive (like potassium) will reactive violently with acid. For metals that are not reactive, a reaction will not occur.
  • For a reaction of lead with either hydrochloric acid & sulfuric acid, the liberation of hydrogen gas is initially observed. However, the liberation of hydrogen gas will then stop, due to the formation of lead(II) chloride and lead(II) sulfate, which are insoluble salts that ‘shield’ the lead metal from further reaction.

Acids react with oxides & hydroxides to produce water and salt. 

  • This reaction is also known as a neutralisation reaction.
  • This reaction, especially the one between acid and hydroxide, is commonly observed in titration (volumetric analysis).

Acids react with carbonate to produce carbon dioxide, salt and water.

  • The production of carbon dioxide and water can be linked to the thermal decomposition of metal carbonates.

The topic Acids and Bases is quite commonly tested in Singapore-Cambridge GCE ‘O’ Level Examinations, with specific association with the following topics:

  1. Stoichiometry
  2. Qualitative Analysis (also known as volumetric analysis)
  3. Salts
  4. Chemical Bonding

CHEMISTRY – Tests for Presence of Organic Compounds

In Organic Chemistry, students will ‘encounter’ questions on the test of unsaturated organic compounds (typically alkene) and alcohol, which is less common.

Firstly, unsaturated organic compound is defined as an organic compound with double or triple carbon-carbon bond. As unsaturated organic compound react with bromine, bromoalkane, in an addition reaction with bromine, known as bromination.

For the identification of alcohol, students need to recognise that alcohol can oxidise to carboxylic acid, specifically with the use of an oxidising agent, solution of acidified potassium manganate(VII). During this process, the solution of acidified potassium manganate(VII) will turn from purple to colourless.

Hence, in summary,

  1. An unsaturated organic compound can be tested by adding aqueous bromine into the compound. Bromine will turn from brown to colourless.
  2. Alcohol can be tested by adding solution of acidified potassium manganate(VII) solution, under reflux. The solution of acidified potassium manganate(VII) will turn from purple to colourless.

SCIENCES – Practising Fundamental Concepts

One trend observed in the Preliminary papers for Sciences in schools is that setters (teachers) rarely assess students on the fundamental concepts — Preliminary papers are usually set at a higher standard, and this explains the difficulty of the examination. For lower-ability students, you may like to first practice on the IGCSE Past-year Examination Papers, as it is easier, as compared to the Singapore-Cambridge GCE ‘O’ Level Examination, not to mention school Preliminary Examinations.

Students are advised to practice questions in the following orders:

  1. IGCSE Past-Year Papers
  2. International GCE ‘O’ Level Past-Year Papers
  3. Singapore-Cambridge GCE ‘O’ Level Past-Year Papers
  4. Past-Year Preliminary Papers

We will also be uploading questions for students to practice their fundamental concepts, and also application questions.