Accuracy and precision
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👩 Teacher’s Guide
🎯 Objective
Students will be able to:
- Define accuracy and precision and give examples of each
- Identify sources of random and systematic error
- Suggest improvements to increase accuracy and/or precision
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📝 Teaching Notes
- Key idea to emphasize: Main concept: accuracy is closeness to true value; precision is repeatability.
- Common misconception: Misconception: accuracy and precision are the same thing.
- Suggested teaching approach:
- Use target diagrams to illustrate both.
- Separate random vs systematic errors.
- Suggest method changes to improve each.
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💬 Discussion Starter
Ask students:
- Why is evidence more important than opinion in science?
- What makes an experiment a “fair test”?
- How can scientists disagree and still make progress?
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🧒 Student Worksheet
Concept and Helping Material
Accuracy is how close you are to the true value, and precision is how consistent repeated measurements are. Understanding errors helps you improve both.
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Vocabulary and Definitions
- — Closeness to the true value.
- — How close repeated measurements are to each other.
- — Unpredictable variation that affects precision.
- — A consistent error that shifts all results.
- — Checking and adjusting a tool to improve accuracy.
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Hands-On Experiment or Activities
Activity 1: Target Diagram Activity
What You Need: target diagrams, sticker dots.
What You Do: Place dots to represent measurements; label each as accurate/precise and explain.
Think and Talk: What changed? What stayed the same?
Activity 2: Error Hunt
What You Need: equipment with deliberate setup issues (e.g., mis-zeroed balance).
What You Do: Find and describe possible random/systematic errors and how to fix them.
Think and Talk: What changed? What stayed the same?
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Practice Questions (QA)
1. What is accuracy?
2. What is precision?
3. Which type of error affects precision most?
4. Which type of error shifts all results the same way?
5. Give an example of random error.
6. Give an example of systematic error.
7. How can calibration improve results?
8. If results are precise but inaccurate, what might be wrong?
9. How do repeats help?
10. Why record uncertainty?
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Reflection
- How could accuracy and precision help you make a better decision in real life?
- What is one habit you can practice to improve your scientific thinking?