Mathematics Advanced Year 11 - Module 3 - Lesson 13
Volumes of Solids of Revolution
1. Key Ideas
Spin a curve around an axis and it traces out a three-dimensional solid — a vase, a rocket nose cone, or a wine glass. By slicing that solid into infinitely thin disks and adding up their volumes, we can find the exact volume of almost any rotational shape. This is the power of volumes of solids of revolution.
- The disk method formula for rotation about the $x$-axis and $y$-axis
- How revolving a curve generates a three-dimensional solid
2. Success Criteria
By the end, you should be able to:
- The disk method formula for rotation about the $x$-axis and $y$-axis
- The washer method for regions between two curves
- How to identify the radius function for a given solid
3. Key Terms
4. Activity: Build the Lesson Map
Use the lesson to complete the table. Keep answers brief but specific.
| Prompt | Your answer |
|---|---|
| Main concept | |
| Important example | |
| Common mistake to avoid | |
| How this links to the next lesson |
5. Short Answer Questions
1. Explain this lesson goal in your own words: "The disk method formula for rotation about the $x$-axis and $y$-axis". Use one specific example from the lesson.
2. Apply this idea to a new example: "The washer method for regions between two curves". Show your reasoning clearly.
3. Analyse why this idea matters for understanding Volumes of Solids of Revolution: "How to identify the radius function for a given solid".
6. Extend: Apply the Idea
A student gives a memorised answer about Volumes of Solids of Revolution but does not use evidence or reasoning.
Improve the answer by writing a stronger response that uses accurate terminology, a relevant example and a clear explanation.
7. Multiple Choice
1. What is the best first step when answering a question about Volumes of Solids of Revolution?
A. Identify the key concept being tested
B. Write every fact from memory
C. Ignore the command word
D. Skip examples and evidence
2. Which answer would show stronger understanding of Volumes of Solids of Revolution?
A. An answer with accurate terms and reasoning
B. A copied definition only
C. A single-word response
D. An answer with no example
3. What should you do if a question asks you to explain?
A. Link the idea to a reason or cause
B. List unrelated facts
C. Only draw a diagram
D. Write the shortest possible answer
8. Success Criteria Proof
Finish with evidence that you can do each success criterion.