Caffeine And Reaction Rates Topic Reaction rates Introduction Caffeine is a drug found in coffee, tea, and some soft drinks. It is a stimulant used to keep people awake when they feel tired. Some people find the effect so strong that they cannot sleep if they drink caffeine-containing beverages during the evening. Other people find the effect is limited or non-existent. In this experiment, you will look at the effect of caffeine on reaction times. If caffeine is a strong stimulant, it is reasonable to assume that it will help people to react more quickly. Using a simple ruler, you can produce a measure of reaction times and thus a measure of any changes following caffeine consumption. Time required 0 minutes Materials ruler 0. or meter supply of caffeine strong black coffee, or a drink containing caffeine calculator Safety note Caffeine is a harmless, readily available stimulant that most people tolerate with no ill effects. Students with an adverse reaction to caffeine in coffee should not do this experiment. Procedure This experiment is carried out in pairs or a small group.. Ask one person (the experimenter) to hold a ruler so that the bottom end dangles between the opened fingers of a second person (the subject) as shown in diagrams and on the next page.
experimenter holding onto ruler scale on ruler ruler subject with ruler loose Relationship between experimenter and subject Ruler dangling between the thumb and fingers. When the experimenter releases the ruler, the subject should catch it by closing his fingers. Record the position on the scale where the fingers catch the falling ruler in the data table on the next page. This is taken as a measure of reaction time the further the ruler has fallen, the slower the reaction time. If the subject fails to catch the ruler, record a value of meter. Repeat this step at least times.. The subject should then take a dose of caffeine either from coffee or a caffeine-containing drink.. Test the reaction time using the same method minutes after taking the caffeine dose, then again minutes later and again after another minutes. Analysis. What was the average value for the reaction time in the first set of trials?. What was the average value for the reaction time in the second set of trials?. Do your results suggest that caffeine improves reaction times? Explain your answer using data from your investigation.. One researcher suggested that any improvement in reaction times was due to subjects learning to react more quickly and not to the caffeine. How could you investigate this idea to see if it was true? Want to know more? Click here to see what we found.
DATA TABLE. No caffeine. Caffeine + minutes. Caffeine + 0 minutes. Caffeine + 0 minutes
,. Results will vary.. Results will vary but expect to see an improvement in reaction times with caffeine.. Test two groups of subjects without caffeine, and then give one group a caffeine dose and the other group a fake (a placebo). Retest both groups. Compare the percentage change in reaction times before and after taking the caffeine in both groups. If caffeine is responsible for any effect, this should only be noticeable in the caffeine group. If learning the technique is
responsible, then both the caffeine group and the control group should show an equal improvement. This investigation will allow you to see the relative importance of the caffeine and the learning effect (if any) by comparing the improvements made by both groups. It is possible to buy a number of other herbal stimulants or relaxants at nutrition or health food stores you could try these to see how they affect reaction time. It is also possible to write a simple computer program to check reaction times this may be easier than using rulers if sufficient computers are available. You could extend the experiment further by looking at the effects of caffeine on other mental functions (e.g., solving puzzles or mentally adding columns of numbers) to get a wider view of what this common stimulant can, and can t, do. You could also use a memory game such as the one where a subject is allowed to look at objects on a tray for a certain length of time before the tray is covered and the subject has to list the objects or answer a series of questions about them.