Some factors affect human reaction time (e.g. the time taken to catch a ruler after it is dropped).
Writing a testable prediction or hypothesis about the effect of a factor on human reaction time.
Identifying independent and dependent variables, range of values to test, and which factors to control and how.
Safe use of apparatus, and safe and ethical use of human test subjects.
Interpret data from measurements of human reaction time.

Common misconception

Describing and identifying independent, dependent and control variables and following a method with care and accuracy are skills that take time to build and need frequent revisiting.

The variables in the practical and the method are outlined and discussed. Considerations on the ethicality of the experiment due to human subjects, and the presence of anomalous data, are also covered in detail.

Keywords

Reaction time - The time taken to react to an event.
Ethical - Something that is morally good and does no harm.
Variable - Something that can be changed, measured or controlled in an experiment.
Prediction - A scientific prediction is a testable statement about a possible outcome of an experiment.

Ensure that students take their time with the practical so that the student subject is not rushed or pressured, that the results collected are of good quality, and that poor data is not collected and the procedure repeated to gain better results and avoid anomalous data. More repeats are encouraged.

Teacher tip

Equipment

Ruler (30 cm or 1 m)

Content guidance

Risk assessment required - equipment

Supervision

Adult supervision required

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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Starter quiz

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6 Questions

Q1.

If an insect flies towards our eye, we blink to protect our eye. Which common life processes enable us to react in this way?

excretion

growth

Correct answer: movement

reproduction

Correct answer: sensitivity

Q2.

The system of the human body enables us to detect and react to changes in our internal or external environment.

Correct Answer: nervous

Q3.

A change in our environment that is detected by our nervous system is called __________.

an effector

a receptor

a response

Correct answer: a stimulus

Q4.

The eye contains sensory __________ that detect light. This enables us to see an insect flying towards us.

detectors

Correct answer: receptors

reactors

stimuli

Q5.

When sensory receptors in the eye detect light, they transmit impulses along sensory in the peripheral nervous system.

Correct Answer: neurones, neurons, neurone, neuron

Q6.

We blink in response to an insect flying towards our eye. Match each keyword to the correct structure.

Correct Answer:effector,Muscles in the eyelid that contract to make us blink.

Muscles in the eyelid that contract to make us blink.

Correct Answer:motor neurone,Nerve cell that transmits impulses from the CNS to the eye.

Nerve cell that transmits impulses from the CNS to the eye.

Correct Answer:spinal cord,Structure in CNS, receives nerve impulses from receptors in the eye.

Structure in CNS, receives nerve impulses from receptors in the eye.

Q4 Alexander_P/Shutterstock

Exit quiz

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6 Questions

Q1.

What is the correct definition of reaction time?

The time taken for a nerve impulse to travel along a motor neurone.

The time taken for a nerve impulse to travel along a sensory neurone.

The time taken for a stimulus to be detected by receptors.

Correct answer: The time taken to react to a stimulus.

Q2.

Some students plan investigations into reaction time in a human participant. Whose investigation would be considered ethical?

Andeep: Poke them with a sharp pin and time their reaction to the pain.

Correct answer: Izzy: Time how long it takes for them to say “on” when a lamp is switched on.

Jun: Compare their reaction times before and after eating a large dose of sugar.

Q3.

Put the method steps in order to describe how to measure the reaction time of a test subject using the ruler drop test.

1 - Hold ruler with the 0 cm end aligned with the subject’s thumb and forefinger.

2 - Without any countdown, let go of the ruler.

3 - The subject must catch the ruler as quickly as they can.

4 - Record the distance at which the ruler was caught.

Q4.

The ruler drop test can be used to investigate reaction time. In one test, the person catches the ruler at a distance of 33 cm. Use the table to convert this result to a reaction time.

Correct Answer: 0.26, 0.26 s, 0.26s, 0.26 seconds

Q5.

The test subject caught the ruler at 52 cm with their left hand, and at 59 cm with their right hand. Which hand had the fastest reaction time?

Both hands had the same reaction time.

Correct answer: The left hand had the fastest reaction time.

The right hand had the fastest reaction time.

Q6.

The test subject caught the ruler at 52 cm with their left hand, and at 59 cm with their right hand. What can you conclude about whether they are left-handed or right-handed?

It’s not possible to conclude this from the results.

Correct answer: The left hand appears to be their dominant hand.

The right hand appears to be their dominant hand.

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