Required Practical 7: Reaction Time

What is meant by reaction time?

The time taken to respond to a visual stimulus.

What is the stimulus in the ruler drop experiment?

The visual stimulus is the ruler falling.

Which receptor detects the stimulus in this practical?

Photoreceptors in the eye detect the ruler falling.

What is the pathway of information during the reaction time experiment?

Eye detects stimulus → sensory neurones carry impulses along the optic nerve to the brain → brain processes information → motor neurones send impulses to hand muscles → hand closes to catch ruler.

What is a hypothesis?

A prediction of the relationship between two variables backed by scientific reasoning.

How do you create a hypothesis?

Observe variables affecting the outcome, choose one to investigate, then form a question and prediction explaining the expected relationship.

Give examples of factors that affect reaction time.

Stress, age, drug use such as caffeine, distractions.

What is the independent variable in the reaction time practical?

The factor that is changed, such as background noise or caffeine consumption.

What is the dependent variable in the reaction time practical?

The distance the ruler falls before being caught, which is converted to reaction time.

Give examples of control variables in the ruler drop experiment.

Use of dominant hand, height the ruler is dropped from, ruler orientation, practice time.

List the basic equipment needed for the reaction time practical.

Chair, table, metre ruler, stopwatch, and additional items depending on the factor investigated.

Describe the setup for the ruler drop reaction time experiment.

Person 1 sits with forearm on table and hand over the edge while Person 2 holds a ruler vertically with the 0 cm mark between thumb and finger.

Describe how the measurement is taken in the experiment.

The ruler is released without warning, Person 1 catches it, and the distance fallen is recorded at thumb level.

Why is the experiment repeated several times?

To improve reliability and allow calculation of an average result.

Why do participants swap roles?

To collect data for both individuals and improve reliability of results.

How are results converted into reaction time?

A conversion table is used to change ruler distance measurements into time values.

What conclusion can be drawn from lower reaction time values?

Lower reaction time means faster responses.

How are results analysed?

Calculate averages, compare conditions, and evaluate whether they support the hypothesis.

Why is this experiment prone to error?

Many variables are difficult to control and practice effects can influence results.

Suggest improvements for the reaction time practical.

Measure time in milliseconds, use more participants and trials, or use computer software for more precise measurement.

What is an alternative method to measure reaction time?

Using a computer program where participants click when a screen colour changes.