Introduction
All GCSE Chemistry specifications include practical work related to energy changes, although the exact investigations differ between AQA, Edexcel and OCR. Regardless of the exam board, students are expected to measure temperature changes accurately, identify exothermic and endothermic reactions, analyse results and evaluate practical methods.
Summary
• Practical investigations measure energy changes by monitoring temperature.
• Exothermic reactions increase the temperature of the surroundings.
• Endothermic reactions decrease the temperature of the surroundings.
• AQA, Edexcel and OCR assess similar practical skills using different investigations.
• Students should understand sources of error and improvements.
• Practical questions are common in GCSE examinations.
Practical Investigations Across the Exam Boards
| Exam board | Typical practical | Main measurement |
| AQA | Reacting acid and alkali in an insulated cup | Temperature change of the reaction mixture |
| Edexcel | Burning alcohols to heat water | Temperature change of the water |
| OCR | No directly equivalent required practical | Understanding energy changes and practical techniques |
Which Energy Changes Practical Will I Do?
The investigation you complete depends on your exam board:
- AQA usually investigates neutralisation using an acid and alkali.
- Edexcel investigates the energy released by burning alcohols.
- OCR assesses similar practical skills through other investigations rather than a single required practical.
AQA-Style Investigation
A common AQA investigation measures the temperature change when an alkali is added in portions to a fixed volume of acid in a polystyrene cup placed inside a beaker. This neutralisation reaction is exothermic because it transfers energy to the surroundings, causing the temperature of the reaction mixture to increase. You can learn more about why this happens in our guide to Exothermic Reactions.
Figure 1: Typical AQA apparatus.
Figure 2. Temperature–volume graph for the AQA neutralisation practical showing the maximum temperature at the equivalence point.
Edexcel-Style Investigation
A typical Edexcel investigation measures the energy released when an alcohol fuel is burned beneath a container of water.
Figure 3: Simple calorimetry apparatus used to investigate the energy released by burning fuels.
Common Practical Skills
- Measure temperatures accurately.
- Record results.
- Calculate temperature changes.
- Identify exothermic and endothermic reactions.
- Evaluate methods and suggest improvements.
Variables, Sources of Error and Improvements
| Practical | Typical source of error | Possible improvement |
| AQA | Heat loss | Use a lid and better insulation |
| AQA | Thermometer reading errors | Use a temperature probe/data logger |
| Edexcel | heat loss | Use a draught shield and insulate sides of beaker |
| Edexcel | incomplete combustion | Reducing the distance between flame and container. |
Common GCSE Exam Mistakes
- Confusing exothermic and endothermic reactions.
- Forgetting the starting temperature.
- Ignoring heat loss.
- Not explaining why insulation improves accuracy.
Exam Tips
• Know the practical used by your specification.
• Mention heat loss when evaluating.
• Suggest realistic improvements.
How This Topic Links To Other GCSE Chemistry Topics
- Energy changes
- Exothermic reactions
- Endothermic reactions
- Reaction profiles
- Activation energy
- Bond energies
Final Thoughts
Although the practical investigations differ between AQA, Edexcel and OCR, they all assess the same core scientific skills. Understanding how energy changes are measured, interpreted and evaluated will help you answer both practical and theory questions with confidence. For a detailed overview of other topics, see our GCSE Chemistry revision guide.
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