Describe how to do the ruler-drop test - AQA - GCSE Biology Combined Science - Question 1 - 2019 - Paper 2

Group A drank water to serve as a control group. This allows for comparison against the groups consuming caffeine, helping to determine the specific effects of caffeine on reaction time.

Using Table 2, a distance of 23 cm corresponds to a reaction time of approximately 0.198 s. This can be found by interpolating between the values for 20 cm (0.181 s) and 26 cm (0.221 s).

As the mass of caffeine increases, the decrease in reaction time tends to be greater. This suggests that higher caffeine doses are more effective in reducing reaction time, likely due to caffeine's stimulant properties and its role in enhancing cognitive function.

The negative value indicates that the reaction time was longer after consuming the drink compared to before. This may suggest that those students experienced a decrease in focus or alertness, possibly due to factors such as tolerance to caffeine or individual physiological responses.

The range of results for group C is calculated by subtracting the minimum reaction time from the maximum reaction time. If the maximum recorded time was 0.2 s and the minimum was 0.12 s, the range would be calculated as:

$ext{Range} = 0.2 ext{ s} - 0.12 ext{ s} = 0.08 ext{ s}$

1. The time of day when the tests were conducted to ensure consistency in alertness levels of students.
2. The amount of sleep the students had the night before, as sleep deprivation can significantly affect reaction times.

The ruler-drop test does not involve a reflex action because the students have to consciously decide to catch the ruler. Reflex actions are automatic responses to stimuli that do not require conscious thought, whereas this test involves awareness and decision-making.