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## Introduction

Reaction time is time it takes a person to repond to a stimulis.  For example, reaction time may be the time it takes for a driver to press on the brakes once he or she has seen an obstacle in the road.

## Research Question

Is reaction time the same for visual, auditory and kinesthetic (touch) clues?

## Measuring reaction time - meter stick drop

One way to measure reaction time is to determine the distance a meter stick will fall through the fingers of your lab partner after they have received a visual, auditory or kinesthetic stimulis.
1. Suspend a meter stick between the fingers of your lab partner as shown in the diagram.
2. Drop the meter stick without providing your lab partner any advanced warning.
3. Measure the distance the meter stick falls before your lab partner is able to arrest its fall by pinching it.
4. Since the meter stick will accelearted towards the earth due to gravity, there will not be a linear relationship between the distance fallend and reaction time.  Instead, you may look up the reaction time using the table below.
5. Determine the average reaction time for three trials for each of three conditions:
• Visual clue only - Drop the meter stick when their eyes are open.
• Auditory clue only - Drop the meter stick when your lab partner's eyes are closed.  Say "Now" the moment you drop it.
• Kinesthetic clue - Drop the meter stick when your lab partner's eyes are closed.  Tap them with one hand at the very moment you drop the meter stick with the other.
6. Use the table determine reaction time from the  the distance the meter stick falls before being caught.
7. Construct the following table in your science notebook
 trial 1    (s) trial 2    (s) trial 3    (s) average (s) visual auditory kinesthetic

1. Calculate your average reaction time for each of the three stimuli.
2. Report the average reaction time for each stimulis.
3. Copy the final class data, create averages, and plot the averages.
• How do your reaction times compare with average reaction times for each of the three stimuli?
• What are the average reaction times for each of the three stimuli?
• Name three occupations that require short reaction times.

## Physiology of Reaction Time

• Discuss the physiology of reactions and reaction time.
• What other independent variables could you test?