Curriculum
Science — Third Preparatory
Science — Third Preparatory
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Science — Third Preparatory 2026/2027
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Unit 1 — Chemical Reactions and Their Environmental Impacts
Preview -
Unit 2 — Electricity and Magnetism
Preview
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Unit 3 — Variation of Traits in Living Organisms
Preview
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Unit 4 — Dating Planet Earth
Preview
- 1.1 How do we know that dinosaurs lived millions of years ago?
- 1.2 What is a fossil and how does it form?
- 1.3 Types of fossils
- 1.4 The fossil record
- 1.5 The importance of the fossil record
- 1.6 Causes of the diversity of life forms through time
- 1.7 Comparative anatomy
- 1.8 Summary of Lesson 1
- 2.1 How old is Earth?
- 2.2 The geologic time scale
- 2.3 Reading Earth's history from rocks and fossils
- 2.4 Determining the age of rocks
- 2.5 Relative age
- 2.6 Absolute age
- 2.7 Comparing relative and absolute dating
- 2.8 Exploiting resources and extinction (issue)
- 2.9 Summary of Lesson 2
- How a fossil forms, step by step
- How to read a rock column (relative dating)
- Choosing a dating method
- Half-life calculation recipe
- Common mistakes
- 📌 Comprehensive Scientific Terminology & Definitions:
- ⚖️ Governing Scientific Laws, Principles & Mathematical Formulas:
- 🔍 In-Depth Explanations, Deductions & Core Concepts:
- 📊 Common Radioactive Isotopes Used in Absolute Geological Dating:
- 💡 High-Yield Exam Traps & Key Takeaways:
Unit 1 - Force, Motion, Acceleration and Physical Quantities
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Text lesson
Unit 4 — Dating Planet Earth
Unit 4 — Dating Planet Earth
2.7 Comparing relative and absolute dating
2.7 Comparing relative and absolute dating
| Point | Relative age | Absolute age |
|---|---|---|
| Meaning | Whether a rock is older or younger than another | The actual age in years |
| Given in years? | No | Yes |
| Principle | Law of superposition and index fossils | Radioactive decay and half-life |
| Used for | Arranging events in order | Finding the exact age of rocks and fossils |
- Critical thinking. Relative dating is needed when no radioactive material suitable for measurement is present (for example in many sedimentary rocks), or when only the order of layers is needed.
- Often both methods are used together.
- Index fossil vs transitional fossil. An index fossil is a fossil of an organism with a short time range and a wide distribution, used to date and match rock layers.
- A transitional fossil shows features of two groups and supports evolutionary change (Archaeopteryx).
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