Lesson 3: Reaction Time RP

Question 1

What is the method of testing for someone’s reaction time?

Answer 1

1.) Person 1 sits on a chair with good, upright posture.
2.) Person 1 places forearm of their dominant arm across the table - with their hand hanging over the edge.
3.) Person 2 holds a ruler vertically. The 0cm mark betwen Person 1’s thumb and first finger.
4.) Person 2 will drop the ruler randomly, person 1 will catch the ruler as quick as possible.
5.) Record the number on the ruler that is level with the top of Person 1’s thumb.
6.) Have a short rest, repeat the test serveral times and calculate a mean.
7.) Repeat the test with Person 2 catching the ruler and person 1 dropping it.
Use a conversion table to convert measurements into reaction times.

Question 2

What do we use to convert the ruler measurements from the experiment into a reaction time?

Answer 2

• We use a conversion table.

Question 3

What are 2 control variables for this practical?

Answer 3

• Starting distance between a specific person’s thumb and first finger should be kept constant.
• Keep conditions in the room the same (ie. lighting/ background noise)

Question 4

What are some independent variables that we could have in this practical?

Answer 4

• The person who’s catching the ruler.
• Effect of practise
• Dominant vs non- dominant hand (of the same person.)
• Effect of chemicals ie. caffeine.

Question 5

What is the dependent variable in this practical?

Answer 5

• Dependent variable = reaction time.

Question 6

How would you investigate the effect of practise on reaction time?

Answer 6

• 1 person catches the ruler a large number of times.
• See if reaction time of the person changes the more tries they have.

Question 7

How wold we investigate the effect of caffeine on reaction time?

Answer 7

• Person will carry out experiment normally and record their reaction time.
• Drink 25cm3 of cola (with caffeine) half an hour before the 2nd experiment.

Question 8

Why do we need to carry out the investigation with caffeine- free cola as well as caffeinated cola when experimenting the ffect caffeine has on reaction time?

Answer 8

• Acts as a control.
• There may be other chemicals in the cola that are effecting the person’s reaction time.