Question 1
A person touches a hot object and their hand moves away without them thinking. Describe the path taken by the nerve impulse in this reflex action.
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- impulse travels along the sensory neurone (from the receptor) to the CNS / spinal cord (1)
- impulse crosses a synapse to the relay neurone (1)
- impulse passes (across another synapse) to the motor neurone (1)
- motor neurone carries the impulse to the effector / muscle, which contracts (1)
- Max 3
Question 2
A student measured her reaction time five times using a computer test. The results were 0.26 s, 0.24 s, 0.31 s, 0.27 s and 0.28 s. Calculate her mean reaction time.
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- 0.26 + 0.24 + 0.31 + 0.27 + 0.28 = 1.36 (1)
- 1.36 ÷ 5 = 0.27 s (1) allow 0.272 s
- allow 1 mark for dividing their total by 5 if the addition is wrong
Question 3
Describe how you could investigate the effect of a distraction, such as music, on a person’s reaction time using a ruler.
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- partner holds ruler vertically and drops it without warning; the person catches it and the distance is read from the ruler (1)
- repeat with and without the distraction (1)
- control variables stated, such as the same person, the same hand and the same drop height (1)
- repeat several times and calculate a mean (for each condition) (1)
- allow: a shorter distance means a faster reaction