MEASURING REACTION TIME

MEASURING REACTION TIME

Objectives

1. Calculate your reaction time and compare it to the reaction time of the class.
2. Compare the reaction time of males and females in the class.
3. Compare the reaction time in terms of age for the class.

Theory

If an object is released from rest the distance it falls is given by the equation:

In this Equation:

g =9.80 m/s² (acceleration of the meter stick which is constant for all objects near the earth surface).

T= Time of fall of the meter stick. (time from when the meter stick is released to when it is caught). This is the reaction time.

The reaction time is given by the equation:

Equipment

1. meter stick.

Procedure

1. Have your lab partner, whose reaction time is being measured, place his/her forearm on the lab bench with the fingers overhanging the edge. This is to prevent your partner from moving their arm downwards, chasing after the falling ruler.
2. Suspend the ruler between your partner’s thumb and finger, held about 1 cm apart. Drop the ruler without warning while the first partner attempts to catch it.
3. Record the distance the ruler fell.
4. Repeat ten times.
5. Calculate your reaction time for each run and then calculate your average reaction time.
6. Change places with your partner and repeat steps 1 – 5. THEORY

Data

Round 1

Round 2

Calculations

Reaction time (sample)

Dollar Bill:

Size 16cm x 7cm

Analysis

The average reaction time between men and women is the same, and hence there is no difference in reaction time. Research shows that a reaction time starts to decline at the age of 24 years. The person with the fastest reaction time in class is ______. My reaction times improved over time because I had a higher reaction time on my first trial and low reaction time in my 10^th trial. When I measured the length of a dollar bill, it was 16cm, and from my reaction time, I am able to catch the dollar bill at the height of 7.66 cm. When I tried the experiment, I was able to capture the dollar bill in the majority of the trials.

Conclusion

1. The reaction time for my partner and I are 0.189 and 0.125 seconds, respectively. I estimated using my reaction time if I was able to catch a dollar bill, and I realized It was right at a distance of 7.66cm.   However, there are errors that resulted from the experiment, which resulted from estimating the gap between the thumb and the finger. Also, the ruler might not have been perpendicular to the earth’s surface. The percentage error of my experiment was 4%, which is within the acceptable range.
2. The objective of the experiment was to calculate my reaction time and to compare with that of a classmate, to compare the reaction time between male and female and to compare the reaction time in terms of age in class. It was not possible to compare the reaction time with the classmates because it is online classes. However, the objective of calculating the reaction time with my partner was achieved.
3. The major systematic error in the experiment is the position of the ruler. If the ruler was placed past the hands of the partner, the experiment could result in a systematic error that cannot be noticed. For example, if the ruler was down by 0.5cm, and the average distance is 8cm, the error is 6.25% (0.5/8 *100%). The error results in greater reaction time that the actual reaction time.
4. The random error might have been cost by variation of the distance between the thumb and the finger. When the distance is small, the reaction time is short, and when the distance is large, the reaction time is long. The systematic error percentage in the experiment was about 4%.