Understand the key components of valid experimental design by evaluating a sample experiment against a comprehensive checklist.
Experimental Design Checklist
Score: 0 / 8 components
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Sample Experiment
Aim: Does temperature affect the solubility of potassium nitrate (KNO₃) in water?
Independent variable: Temperature of water (20°C, 40°C, 60°C, 80°C)
Dependent variable: Mass of KNO₃ dissolved per 100 mL water
Controlled variables: Volume of water, stirring rate, type of salt, container
Use the checklist below to evaluate whether this experiment is well-designed. Tick each component you think has been addressed.
Reflection — Working Scientifically
A well-designed experiment must include all 8 components to be considered scientifically valid. Missing any of these introduces potential sources of error or bias.
Key points for this experiment:
The aim is clearly stated with a specific question
The hypothesis should predict the relationship (e.g., "As temperature increases, solubility of KNO₃ increases")
All three variable types are explicitly identified
The method should include step-by-step instructions with safety precautions
Risk assessment is essential when working with hot equipment
Results should be recorded in a table with proper units and repeated trials
Analysis should include a graph of solubility vs temperature
The conclusion must directly address the aim and hypothesis