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To investigate the reaction time and the factors affecting them

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Introduction

Romin Parekh X - B Biology Lab Experiment Aim To investigate the reaction time and the factors affecting them Theory The Nervous System It involves the compiling of information and then responding to, changes in the environment either inside or outside the body. This system has receptors which sense the stimulus and then pass it on through the sensory neurones to the central nervous system (C.N.S). The C.N.S consists of the brain and the spinal cord and it processes all the information and then responds to them by sending the signals through the motor neurones to the effectors (muscles or organs). The effectors put forward the plan of action bringing about a response. The relay neuron however sends the processed information from the C.N.S to the motor neuron. Stimulus Receptor Central Nervous System Effectors Response Sensory neurones carry signals from sense organs to the spinal cord and brain. Relay neurones carry processed data from one part of the C.N.S to another. Motor neurones carry signals from the CNS to muscles and other effector organs. Information is sent electrochemically. In the neurone, they are sent in the form of nerve impulses (electrically) down the length of the axon which is insulated by the Myelin Sheath. While between two neurones, when the information is going to be sent, a chemical called Neurotransmitter is secreted with help of which they are sent between two neurones. ...read more.

Middle

* Make sure that the distance between the two fingers should be 5 cm. * Tell the subject when you will be dropping the meter rule 5 seconds in advance. * Ask the subject to concentrate on the falling meter rule. * Repeat the experiment with other Male and Female subjects and their respective right and left hands. Results Right Hand Sr. No. Subject Initial Reading (cm) Final Reading (cm) Reaction Time (Change (cm)) Males 1. Abhishek 0 14 14 0 13 14 0 10 10 2. Mustafa 0 8 8 0 6 6 0 6 6 3. Sagar 0 18 18 0 17 17 0 13 13 Females 4. Sayali 0 14 14 0 13 13 0 12 12 5. Jahnavi 0 16 16 0 15 15 0 12 12 6. Shloka 0 12 12 0 10 10 0 9 9 Left Hand Sr. No. Subject Initial Reading (cm) Final Reading (cm) Reaction Time (Change (cm)) Males 1. Abhishek 0 16 16 0 13 13 0 12 12 2. Mustafa 0 9 9 0 8 8 0 7 7 3. Sagar 0 21 21 0 20 20 0 17 17 Females 4. Sayali 0 15 15 0 15 15 0 13 13 5. Jahnavi 0 18 18 0 17 17 0 17 17 6. Shloka 0 10 10 0 8 8 0 7 7 Note Subject Gender Preferred Hand Age (years) ...read more.

Conclusion

Average Reading = (Sum of all left and right hand readings) No. of readings Male = 229/18 = 12.7222 = 12.72 cm (2 decimal places) Female = 233/18 = 12.9444 = 12.94 cm (2 decimal places) Fair Test * All the subjects were told when the meter rule was going to be dropped 5 seconds in advance. So it was not a reflex action. * All subjects were asked to concentrate on the meter rule. * The distance between the two fingers was kept at 5 cm. Factors Affecting the Reaction Time * Practice and Error * Fatigue * Sex * Age * Distractions * Finger Tremors * Left and Right hand * Vision Errors * The distance between the two fingers could have marginally changed and not have been 5 cm. * The meter rule could not have been at the exact eye level. * The readings were rounded off to the nearest integer. Error Analysis Inaccuracy = Smallest reading of apparatus / 2 Total Error = Inaccuracy x No. of times used Systematic Errors * Meter rule (+ 0.05 mm) Total Error = + 0.05 x 18 = 0.9 mm Improvements 1. The reading should be rounded of to the nearest integer. 2. Subjects of different age groups should be chosen to note the trend followed. 3. The subjects can be told 10 seconds in advance so that they are able to concentrate more giving accurate readings. 1 ...read more.

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