IB Sciences seem impossible at first. Biology feels like a memory test, Physics feels like a math test, and Chemistry is a confusing mix of both. But the students who get 7s across the board often known as "Triple Crown" students don't reinvent the wheel for each subject. They just understand the system.
This guide explains exactly how to adjust your study habits for the specific demands of each subject. We focus on the "Marking Algorithm," which is the specific way examiners are told to grade your papers.
1. Biology HL: The Vocabulary Trap
The most common complaint from Biology students is that they wrote a page of information, understood the concept, but still got zero marks. This happens because IB Biology is not a test of general knowledge. It is a test of specific terminology. The mark schemes are incredibly pedantic. You can explain a concept perfectly in plain English and receive no credit because you didn't use the mandatory keyword.
To fix this, stop summarizing your textbook into your own words. In Biology, "your own words" are dangerous. Instead, you need to reverse-engineer the mark scheme. For every major process like DNA Replication, Translation, or Photosynthesis find the long-answer questions from past papers and copy the mark scheme answers exactly. Memorize those specific phrases. For example, don't say "the enzyme cuts the DNA." Say "Restriction endonucleases cleave the phosphodiester bonds." The difference between a 4 and a 7 is usually just vocabulary.
2. Chemistry HL: Connecting the Topics
Chemistry often feels overwhelming because it seems like an endless list of disconnected facts. You study bonding, then stoichiometry, then organic chemistry, and they all feel like separate islands. The secret to Chemistry HL is realizing that the subject is modular. Topic 1 (Stoichiometry) is not a chapter you finish and forget; it is a tool you must use in Topic 8 (Acids) and Topic 9 (Redox).
You must focus on the foundations first. If you cannot effortlessly convert mass to moles (\(n = m/M\)), you will fail Equilibrium and Kinetics questions later. Once the math is solid, focus on understanding mechanisms rather than memorizing reactions. In Organic Chemistry, don't memorize every single reaction as a unique event. Learn why a double bond is an area of high electron density, and you will understand why electrophiles attack it. When you study Periodicity, force yourself to explain the trends using Atomic Structure. Connect the dots between the chapters, and the workload drops significantly.
3. Physics HL: Identifying the Variables
Physics is often the most feared science because you cannot memorize your way through it. You can define "Simple Harmonic Motion" perfectly, but that won't help you solve a complex mechanics problem involving a spring and a pulley. The key here is to stop staring at the problem and start auditing the data.
When you are stuck, look at the numbers you have been given. Write down every variable explicitly (e.g., \(u = 0\), \(t = 5\), \(a = 9.81\)). Then, write down the target variable you need to find. Finally, go to your data booklet and find the single equation that links the variables you have with the variable you need. This turns a terrifying physics problem into a simple matching game. It removes the panic and gives you a logical step-by-step process to follow.
4. Tracking Your Mistakes
Regardless of which science you study, the most efficient way to improve is to track your errors obsessively. When you get a question wrong in practice, do not just check the answer and move on. That is a wasted opportunity. You need to write down exactly why you got it wrong.
Did you not know the content? Did you misread the command term? Did you make a calculation error? By writing this down in a dedicated notebook or spreadsheet, you create a personalized map of your weaknesses. Review this list before every single exam. It is the fastest way to stop making the same mistakes twice.
Science at the HL level is not about knowing everything. It is about knowing exactly what the examiner wants to hear. If you master the mark scheme, the content becomes much easier to handle.