Subject: Physical Sciences Grade: 12 (Matric) Focus: Physics (Mechanics, Electricity) and Chemistry (Matter, Change)
Introduction
Physical Sciences is a two-paper subject. You need to master both the “Physics” side (formulas and calculations) and the “Chemistry” side (reactions and molecules).
This guide breaks down the curriculum based on the Examination Guidelines.
Paper 1: Physics (150 Marks)
Physics is about applying laws to real-world situations.
1. Mechanics (±63 Marks)
This is the biggest section.
- Newton’s Laws:
- Newton 1: Inertia (objects keep doing what they’re doing).
- Newton 2: F_net = ma. This is the most tested formula. Know how to draw free-body diagrams for slopes and hanging masses.
- Newton 3: Action-reaction pairs.
- Work, Energy & Power:
- Work-Energy Theorem: W_net = Delta (K). This theorem links force and velocity.
- Conservation of Mechanical Energy: Only use this when there is no friction.
- Momentum & Impulse:
- Conservation of Momentum: sum of momentum(p) _ before = sum of momentum(p) _ after. Crucial for collisions (cars crashing, balls bouncing).
2. Waves, Sound & Light (±17 Marks)
- Doppler Effect: The change in frequency when a source moves.
- Formula: $f_L = \frac{v \pm v_L}{v \pm v_s} f_s$. Know when to use $+$ or $-$ (Towards = Higher Frequency).
3. Electricity & Magnetism (±55 Marks)
- Electric Circuits:
- Internal Resistance: Understand why voltage drops when you close the switch.
- Series vs. Parallel: Current splits in parallel; Voltage splits in series.
- Electrodynamics:
- Motors vs. Generators: Know the difference. (Motor = Electrical to Mechanical; Generator = Mechanical to Electrical).
- AC vs. DC: Know the graphs for voltage and current.
Paper 2: Chemistry (150 Marks)
Chemistry is about molecules and how they react.
1. Organic Chemistry (±54 Marks)
This is a huge section and very learnable.
- Nomenclature: Naming compounds (IUPAC rules). Alkanes, Alkenes, Alcohols, Esters, etc.
- Physical Properties: Boiling points and melting points. Understand Intermolecular Forces (Hydrogen bonds vs. Van der Waals forces). Stronger forces = Higher boiling point.
- Reactions: Addition, Elimination, Substitution. Know the conditions (heat, catalyst) for each.
2. Rate and Extent of Reaction (±23 Marks)
- Rates: How to speed up a reaction (Temperature, Concentration, Surface Area, Catalyst).
- Maxwell-Boltzmann Distribution: Be able to draw and interpret this graph.
- Chemical Equilibrium: K_c calculations. Le Chatelier’s Principle is 100% guaranteed to be in the exam.
3. Chemical Change (±43 Marks)
- Acids & Bases: pH calculations, Titrations, Indicators.
- Electrochemical Cells:
- Galvanic Cells: Anode (Oxidation), Cathode (Reduction). Acts as a battery.
- Electrolytic Cells: Using electricity to split chemicals (e.g., Chlorine production).
4. Chemical Systems (±15 Marks)
- Fertilizers: N-P-K ratios. Eutrophication (too much fertilizer causing algae blooms).
My Top Tips for Distinction
1. Master the “Free Body Diagram” In Paper 1, you will be asked to draw forces acting on an object.
- Arrow heads: Must be present.
- Labels: Use standard labels (F_g, N, F_(fric).
- Touching: The arrows must touch the dot (object).
2. Le Chatelier’s Principle (Chemistry) You will be asked to explain a shift in equilibrium. Use the bullet-proof structure:
- “The disturbance is…” (e.g., Temperature increased).
- “According to Le Chatelier, the system opposes the disturbance by…” (e.g., cooling down).
- “The forward/reverse reaction is favoured.”
- “The yield of products increases/decreases.”
3. Definitions are “Free Marks” Physics and Chemistry have very specific definitions (e.g., “Work done by a net force”). Memorize them word for word from the guidelines. Don’t paraphrase.
Conclusion
Physical Sciences is tough, but logical.
- Paper 1: Practice calculations. Be comfortable with your calculator.
- Paper 2: Practice naming organic molecules and explaining equilibrium shifts.
Good luck with your Matric Finals!