🧪 Part 1: Multiple Choice Questions

1. Which factor is MOST likely to increase the rate of decomposition?

Low temperature

High moisture levels

Lack of oxygen

Dry conditions

2. In a controlled decomposition experiment, which variables should be kept constant?

Container type

Temperature

Amount of material

Type of organic matter

3. What is the main purpose of recording data at regular time intervals?

To make the experiment longer

To observe changes over time

To use more equipment

To fill in data tables

4. Which measurement would provide the MOST reliable quantitative data?

"The material looks different"

"Mass decreased by 2.5g"

"It smells bad"

"The colour changed"

✏️ Part 2: Investigation Design and Analysis

5. Complete the method checklist for your decomposition investigation:

Key variable to measure: _________________________________

Range of this variable: _________________________________

How other variables are controlled:

6. Explain why wearing gloves and proper disposal are important safety measures in this investigation:

7. Write a preliminary conclusion based on your Time Point 0 observations. Use the sentence starter:

"Based on my evidence, I predict that..."

8. Label the diagram showing factors affecting decomposition rate:

Draw and label: moisture, temperature, oxygen, and organic material

🎯 Part 3: Extension Challenge

9. Advanced Learners: Design an improvement to increase the reliability of this investigation. Consider how you could reduce subjectivity in qualitative observations or add more quantitative measurements:

10. Compare two decomposition drivers (moisture vs. oxygen exposure). Explain how your controlled conditions help reduce alternative explanations for observed changes: