Homeostasis & ResponseRequired Practical
Required Practical: Reaction Time (RPA7)
Part of Nervous System — GCSE Biology
This required practical covers Required Practical: Reaction Time (RPA7) within Nervous System for GCSE Biology. Topic 2: Nervous System It is section 7 of 17 in this topic. Revise both the method and the reason for each step, because practical questions often test understanding rather than pure recall.
Topic position
Section 7 of 17
Practice
15 questions
Recall
20 flashcards
🧪 Required Practical: Reaction Time (RPA7)
In this practical, you measure reaction time using the ruler-drop method:
- One person holds a ruler vertically at the 0 cm mark between another person's open thumb and forefinger.
- The ruler is dropped without warning — the second person catches it as quickly as possible.
- Read the distance the ruler fell (in cm) and use a conversion table to find the reaction time.
- Repeat at least 5 times and calculate the mean to improve reliability.
Variables:
- Independent variable (what you change): e.g. caffeine intake, practice, distraction
- Dependent variable (what you measure): distance the ruler falls (reaction time)
- Control variables: same ruler, same hand, same starting position, same person dropping
Why repeat and average? Individual readings vary because reaction time is affected by concentration, fatigue, and anticipation. Taking a mean reduces the effect of anomalies and gives a more reliable result.