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Precision vs Accuracy Target Diagram

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Description

This MicroSim uses a target and dart analogy to help students visually distinguish between two important but often confused measurement concepts:

  • Accuracy: How close measurements are to the true (accepted) value
  • Precision: How close measurements are to each other (repeatability)

The visualization displays four targets in a 2×2 grid, each demonstrating a different combination of accuracy and precision:

Target Accuracy Precision What It Means
Top-Left (Blue) High Low Measurements average to correct value but vary widely
Top-Right (Green) High High Measurements are correct and consistent
Bottom-Left (Red) Low Low Measurements are neither correct nor consistent
Bottom-Right (Orange) Low High Measurements are consistent but systematically wrong

How to Use

  1. Observe the dart patterns on each target
  2. Compare how clustered (precise) vs. scattered the darts are
  3. Note how close to center (accurate) vs. offset the darts are
  4. Click "Regenerate Darts" to see new random patterns that maintain the same characteristics

Key Concepts

Accuracy

  • Related to systematic error (bias)
  • Can be improved by calibrating instruments and improving technique
  • The orange target shows high precision with low accuracy—a classic systematic error

Precision

  • Related to random error
  • Can be improved by using better instruments or taking more measurements
  • The blue target shows high accuracy with low precision—measurements scatter but center on the true value

The Goal in Science

Scientists strive for measurements that are BOTH accurate AND precise (green target), where results are close to the true value and highly repeatable.

Lesson Plan

Learning Objectives

By the end of this activity, students will be able to: 1. Define accuracy and precision in measurement contexts 2. Distinguish between systematic and random errors 3. Identify measurement quality from visual data patterns 4. Explain why both accuracy and precision are important in scientific measurement

Grade Level

High School Physics (Grades 9-12)

Duration

15-20 minutes

Activities

  1. Prediction (3 min): Before viewing, ask students what they think "accurate" and "precise" mean in science.

  2. Exploration (5 min): Let students interact with the simulation, regenerating darts multiple times to see the characteristic patterns.

  3. Discussion (5 min): Ask students to describe each target pattern and identify which represents the best measurements.

  4. Real-World Examples (5 min): Have students brainstorm examples of each type:

  5. Accurate & Precise: A well-calibrated digital scale
  6. Accurate but Imprecise: Averaging many crowd-sourced measurements
  7. Precise but Inaccurate: A miscalibrated instrument
  8. Neither: A broken or unreliable instrument

Assessment Questions

  1. If all your measurements are clustered together but far from the accepted value, what type of error do you have?
  2. How would you improve the precision of measurements?
  3. Why might a precise but inaccurate measurement be more dangerous than an imprecise measurement?

References

  1. Accuracy and Precision - Physics Classroom - Clear explanation of accuracy vs precision with examples
  2. JCGM 200:2012 - International Vocabulary of Metrology - BIPM - Official definitions of measurement terminology
  3. Precision vs Accuracy - Khan Academy - Video tutorial on measurement concepts