Practical Reaction Time

 

EXPERIMENT: REACTION-TIME Aim: In this experiment, use what you know about falling object to measure reaction time Theory: 1 Free falling object falls through a distance of :   .    

2

where d  is  is distance, t  is  is the time, and g  and g  is  is 9.80 m/s2. Gravity is pulling down on the ruler at a constant rate. The longer it falls, the faster it goes. By measuring how far the ruler falls, we can calculate the speed at which it is moving and the time it took you to catch it. Materials and Tools:

1.  ruler (50 cm) Procedure: 1.  Hold the index finger and thumb of your dominant hand about 2.5 cm apart, and then have your friend hold a ruler vertically in the space between your finger and thumb (as shown in figure A2.2). 2.   Note the position position of the ruler relative relative to your index index finger. finger. 3.  Without warning your friend should let go of the ruler, and you should try to catch it with your fingers as quickly as you can (without moving your hand downward). 4.   Notice what what cm-mark cm-mark your fingers are are on when you catch the ruler. Note the final position of your fingers after you get hold of the ruler. 5.  Repeat the measurement of the distance for 5 times. 6.  Average the results of distance, then calculate the value of average time taken using equation from the theory. That average time is your average reaction time. Experimental Data

value of gravity = 9.80 m/s2  Your name : Trial

Age : 1

2

3

4

5

Average value

Initial position /cm Final position /cm  Distance /cm

Calculation of your reaction-time:

Average value of your reaction-time:

s

Results & Discussion

1.  Why do you think it takes time for your fingers to react r eact when your eyes see the stick start to fall?

2.  Compare your reaction-time with your friends’ reaction-time. Do both of you have the same value? Give  possible reason(s) reason(s) as for why it could could happen. happen. Yes / No,

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Free-fall Object: Reaction Time, Physics Grade X SMA IBC 1st sem., 2015-2016 Devilim, S.Si.

 

3.  Do this experiment with adult (it could be your parent or someone older than you). Record his/her data in the table below and find his/her reaction time. Experimental data

value of gravity = 9.80 m/s2   Name of adult: adult: Trial

age : 1

2

3

4

5

Average value

Initial position /cm Final position /cm  Distance /cm

Calculation:

Average value of reaction-time:

s

Compare his/her result with your reaction time. Who is quicker?

What do you think the reasons why reaction time might be different for an adult and a child?

4.  Explain one benefit of knowing human’s reaction time in daily life.

Conclusion:

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Free-fall Object: Reaction Time, Physics Grade X SMA IBC 1st sem., 2015-2016 Devilim, S.Si.