affect of age on reaction time

                   3. Controlled/constant variables: To have a fair test, so you could have a good, fair-resulted experiment, you have to control a few variables. These are:  

1. Same ruler. The ruler has to be the same height and the same weight so that the person doing the experiment (trying to catch the ruler) will face the same properties of the ruler that the other person did, for example if the ruler was very short, the ruler may fall down before the person even catches it and therefore this will vary and change the results big-time.
2. Same number of people for each age group. This is to have a fair result for each age group in the end as I will find the average of both age groups.

Materials needed: Ruler

Method:

1. Get 21 people, 7 for each group (10-20, 20-30 and 40 and over).
2. Get the material used (ruler).
3. Hold the ruler vertically from the end of the ruler (45 cm).
4. Then let the volunteer spread his thumb and middle finger 8.75 cm apart and centre the ruler between his fingers.
5. Then, let go of the ruler and your volunteer has to try to catch it as fast as possible.
6. Mark the point on the ruler were the volunteer caught it.
7. Do this to all 21 volunteers.
8. Record your results and find the average for each age group.

Data collection

Table #1

Conclusion:

As we can see from the results above, there was a major decrease from each age group. The first age group, which was between 10 years and 20 years, had the best reaction time scoring an average of 25 cm for each catch. This shows us that the age group between 10 and 20 years which mainly contains teenagers is the group with people with the best reflexes scoring the best reaction times as I said in my hypothesis, that this age group will score the best average reaction time as there muscles (effectors) are still new and unharmed therefore reacting quickly to a stimulus. The second age group which was between the ages 20 and 30 years scored the second best average reaction time just as I said in my hypothesis. The difference in the average reaction time between the first and second age group is very minimum (1 cm). This shows us that in the 2nd age group time (from the 20s to the 30s) our muscles (effectors) are still not harmed a lot to therefore decrease the reaction time a lot and react slowly to a stimulus. As the reflexes stayed the same, or weren't affected a lot by this age, the reaction time didn’t differ a lot. As for the third average reaction time for the third age group (60 and over) it was the worse as I mentioned in the hypothesis. We can clearly see that in this age the effectors (muscles) and reflexes in general are affected a lot so therefore this will increase the reaction time a lot. Also, to prove this point, we can see that the difference between the highest age I used before the lowest age (in the last age group) scored an average reaction time of 22cm, cm while the lowest age in the last age group (60 and over) scored 15cm. The difference here is quite large, it is about 7 cm which means that the reaction time was decreased a lot. As we compare the average reaction time of the highest age (28cm) in the first age group (10-20), and the average reaction time of the lowest age (25cm) in the 2nd age group (20-30) we find out that the difference is very minimum (28-25=3) therefore proving my point in the hypothesis (I think that the reaction time will increase as I begin to test older people) right.

Sources of error:

1. The length between the ruler and the hand of the volunteer has to be the same when measured from the lower end of the ruler to his hand. If this wasn’t true in the experiment, the point where the volunteer catches the ruler would’ve varied.

Improvements:

1. Measure the same length between the ruler and the hand of the volunteer. This length has to be measured from lower end of the ruler to his hand in order to have a correct and more accurate table of results. You can do this by simple drawing a small line on a wall behind the volunteer, and then use this height while dropping the ruler for all the volunteers.

Bibliography

1. Williams, David. "Reaction Time Test." David Williams. 13 Jan. 2008 <http://www.drdavidwilliams.com/nc/reaction_time_test.asp>.

2. "Aging's Effects." MERCK. Feb. 2003. 13 Jan. 2008 <http://www.merck.com/mmhe/sec06/ch076/ch076e.html>.

3. "Does Age Affect Reaction Time?" Wikianswers. 13 Jan. 2008 <http://wiki.answers.com/Q/Does_age_affect_reaction_time>.