Measuring Human Reaction Time

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Measuring Human Reaction Time

How does ___ or ____ affect reaction time of humans?

1. The Nervous System

a. What is the main job of the nervous system?

b. Describe the two main parts of the nervous system. Describe the organs that belong to each part and what they each do.

c. Which part of the brain processes seeing the ruler? Which part of the brain controls the muscles moving to catch the ruler?

2. The Neuron

a. Describe a nerve/neuron. Include function, labeled diagram with cell body, dendrite, axon, and synapse.

b. What is an action potential and how does it work?

c. Describe a neurotransmitter. Give at least two examples.

3. The Muscles

a. Name the muscles in the arm and hand that would be involved in contracting to catch the ruler.

b. Describe the structure of a muscle including muscle fibers, myofibril, sacromeres, actin and myosin. A drawing may be helpful.

c. Describe how the muscle contracts and relaxes using actin and myosin.

d. Describe how the nervous system and the muscle are connected to make the muscles contract or relax.

e. Trace the path of stimulus for catching the ruler beginning with your eyes ending with your hand contracting. (In words and/or in a drawing)

4. Reaction Time

a. What is reaction time?

b. What are stimulants? Name two and describe how they work.

c. What are depressant? Name two and describe how they work.

d. What other factors might affect reaction time?

5. My Experiment

a. Why did you choose this topic?

b. Describe your independent variable and why you chose it.

c. Describe your dependent variable and how you plan to measure it.

d. Describe any lab safety rules you need to follow during your experiment.

e. Describe any special equipment you will use in your experiment.

Resource 1: Textbooks

McDougal LIttell, Biology:

▪ Chapter 29: Nervous and Endocrine Systems

▪ Chapter 33: Protection, Support and Movement

▪ Lab Handbook: R2-R4

Prentice Hall Biology:

▪ Chapter 35: Nervous System

▪ Chapter 36: Skeletal, Muscular and Integumentary Systems

Janice VanCleave’s A+ Projects in Biology

▪ Chapter 30: Effect of Stimuli on Reaction Times (189 – 194)

Resource 2: How Fast are You?



Methods

This project does not test a simple reflex. Rather, this activity is designed to measure your response time to something that you see.

Get a ruler (or a yardstick or candy bar). Hold the ruler near the end (highest number) and let it hang down. Have another person put his or her hand at the bottom of the ruler and have them ready to grab the ruler (however, they should not be touching the ruler). Tell the other person that you will drop the ruler sometime within the next 5 seconds and that they are supposed to catch the ruler as fast as they can after it is dropped. Record the level (inches or centimeters) at which they catch the ruler (you can convert the distance into reaction time with the chart below). Test the same person 3 to 5 times (vary the time of dropping the ruler within the 5 second "drop-zone" so the other person cannot guess when you will drop the ruler).

Here is a table to convert the distance on the ruler to reaction time. For example, if you caught the ruler at the 8 inch mark, then your reaction time is equal to 0.20 seconds (200 ms). Remember that there are 1,000 milliseconds (ms) in 1 second.

|Distance |Time |

|2 in (~5 cm) |0.10 sec (100 ms) |

|4 in (~10 cm) |0.14 sec (140 ms) |

|6 in (~15 cm) |0.17 sec (170 ms) |

|8 in (~20 cm) |0.20 sec (200 ms) |

|10 in (~25.5 cm) |0.23 sec (230 ms) |

|12 in (~30.5 cm) |0.25 sec (250 ms) |

|17 in (~43 cm) |0.30 sec (300 ms) |

|24 in (~61 cm) |0.35 sec (350 ms) |

|31 in (~79 cm) |0.40 sec (400 ms) |

|39 in (~99 cm) |0.45 sec (450 ms) |

|48 in (~123 cm) |0.50 sec (500 ms) |

|69 in (~175 cm) |0.60 sec (600 ms) |

This reaction time experiment required visual information (the movement of the ruler) to travel to your brain. Then your brain sent a motor command ("grab that falling ruler") to the muscles of your arm and hand. If all went well, you caught the ruler!!

[pic]Questions and Comparisons

• Try the experiment in dim light. Does your reaction time increase, decrease or stay the same? Can you explain your results?

• [pic]Test the whole class. Who is fastest?

• [pic]Compare boys vs. girls. On average, are the boys or girls faster?

• [pic]Compare different ages. Who is fastest?...the older students or younger students?

• [pic]Compare the scores after practice. Does reaction time improve with practice?

• [pic]Compare kids' scores vs. parents' scores. Who is faster?

• [pic]Test the whole school!!

• [pic]Test the whole city!!................you get the idea.

Your own Reaction Timer



Reaction time is the ability to respond quickly to a stimulus. It important in many sports and day to day activities, though it is not often measured. Simple reaction time is the time taken between a stimulus and movement e.g., sprint start. Such simple reaction time depends on nerve connections and signal pathways, is 'hard wired' in your body composition and cannot be improved. Another type of reaction time, choice reaction time, is the time taken between stimulus and action which requires a choice. Choice reaction time can be improved by practice and training.

Performers receive stimuli from the eyes (position of other players, the ball etc), the ears (calling from players, the referee, even spectators), and kinesthetic sense (the performer's position, their options etc). Skilled players reduce reaction time by selecting the most important information, and by anticipating other players actions and the path of the ball quickly.

Testing Reaction Time

As with all sports fitness testing, specificity is very important, and if you were to seriously want to measure an athlete's reaction time in a certain sport, you would want a test that is more specific to the visual cues and muscle reactions that are encountered during that sport. See a list of reaction time tests at

What is it measuring?

For example, in the click reaction time test, when you see the screen color change, the signal for the change in color travels from your eye along the optic nerve to be registered in your brain, from which a message is sent to another part of your brain that controls your muscles. Your brain must then send a signal along the nerves to your muscles, telling them to depress the mouse button. Signals travel fast along each of the nerve pathways required, however the majority of the reaction time is taken up at the junction points in between the different nerves involved, and between the nerves and the muscles at your fingers.

However, if you compare your results of the click reaction time to the 'make your own' test, you may notice that you get quite different scores, even though the tests are measuring similar abilities. The slight differences between the tests and the computer software may explain the different results you will get.

HUMAN REACTION TIME LAB

How does______________________affect the reaction time of humans catching a ruler?

Independent Variable: _______________________ ( )

Dependent Variable: ________________________ ( )

HYPOTHESIS

If_________________________________________________________________________________________________________,

then_______________________________________________________________________________________________________,because____________________________________________________________________________________________________ _____________________________________________________.

How are you going to test the results of your independent variable on human reaction time? Remember, you will be testing 40 people. ________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

RESULTS: DATA TABLE

Think about how you will be gathering and recording the information or data you gather? You will be collecting data from 40 different people so, based on the nature of your data, your table may need either 40 or 20 rows. Remember to make two more rows for your totals and averages. Use these examples to help you set up your data table(s) on a separate sheet of paper:

Please don’t limit yourself to these examples, the possibilities are endless!

USE A RULER!

Example for Practice:

|Trials |1st try (no practice): |After 5 tries |After 10 tries |

|1. | | | |

|40. | | | |

|Totals: | | | |

|Averages: | | | |

Example for Gender:

|Trials (Boys) |1st try |2nd try |3rd try |

|1. | | | |

|20. | | | |

|Trials |1st try: |2nd try |3rd try |

|1. | | | |

|20. | | | |

Example for Sleep:

|Trials |8 or more hrs. of sleep |

|1. | |

|20. | |

|Trials |Less than 8 hrs. of sleep |

|1. | |

|20. | |

Example for Time of Day:

|Trials |Morning (before 10am) |Afternoon (after 1pm) |

|1. | | |

|40. | | |

RESULTS: DATA ANALYSIS

Example Graphs

Example Graph for Gender:

Example Graph for Practice:

Example Graph for Sleep:

Example of Graph for Nicotine (stimulant):

-----------------------

Gender (boys vs. girls)

Human Reaction Time

(mSec)

[pic]

Number of Tries

Human Reaction Time

(mSec)

[pic]

Hours of Sleep

[pic]

Human Reaction Time

(mSec)

Smokers Vs. Nonsmokers

Human Reaction Time

(mSec)

[pic]

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