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My investigation is to find out whether consuming caffeine affects the body and, if so, in what way. In order to find out I am going to set up an experiment.

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SC1 Aim My investigation is to find out whether consuming caffeine affects the body and, if so, in what way. In order to find out I am going to set up an experiment. Background, research and Theory Caffeine is the ingredient that gives coffee, tea, chocolate and Coca cola (Coke) its kick. It is called a stimulant because it causes a number of physiological effects. Stimulants are drugs which speed up the action of the brain. Caffeine affects the central nervous system and tends to stimulate the release of two key hormones - *epinephrine and norepinephrine. *(Norepinephrine and epinephrine are sometimes called noradrenalin and adrenaline) To understand this I will explain how nerve impulses are transmitted from cell to cell. Passage of nervous impulses from cell to cell Interchange of information involves impulses crossing the small spaces between the nerve endings. These spaces are called synapses. The transfer of impulses across these synapses involves the release of a "transmitter" chemical from one nerve cell, which then quickly diffuses to the next nerve cell in the chain. There are several such neurotransmitter substances. Caffeine belongs to the xanthine chemical group. Adenosine is a naturally occurring xanthine in the brain that is used as a neurotransmitter at some synapses. One effect of caffeine is to interfere with adenosine at multiple sites in the brain. ...read more.


I propose to do each of the tests at least three times and take an average. I will record the results of my pulse and then plot a graph. The coke gave us unreliable results so we decided to consume another substance in this case it was coffee. Firstly I took my resting pulse rate and recorded it on my results table. For this test my partner in the investigation measured out 150ml of hot water, 10ml of milk and 1.5g of coffee granules and poured it in a polystyrene cup. My partner has to do this because activity can disturb the results. Make sure the temperature of the coffee is at 55�c and remains exactly at this temperature for all the tests. Drink the coffee in 25 seconds as changing the time could affect the results so we will try and control temperature and time consumption. After consumption of the coffee take your heart rate and do the reaction time test which was the ruler drop and record it down on the results table after two minutes repeat as before. Record heart rate and ruler drop and keep doing this for every two minutes until 10 minutes. THINGS I NEED TO DO TO MAKE IT A FAIR TEST: 1.) Measure the amounts of coke accurately by using a measuring cylinder of an appropriate size. ...read more.


The pressure of getting the readings and results done in a set time can increase stress and increase adrenalin levels which would increase heart rate. I may have got better at catching the ruler or anticipating when my colleague was going to release it. The measuring of the point on the ruler where I caught it is not really very accurate. A better way to measure reaction times would be by some sort of electronic device such as pressing a button when you see or hear something. There may have been slightly too much or too little coke or coffee in the experiment. To have made the measurements even more accurate I could have used a burette because it would have given a much more precise measurement. Because of the constraints of time it was not possible to take all the readings in the same lesson period. The varying presence of food in my stomach could alter the absorption of the caffeine into the blood stream. Milk can slow down the absorption of the caffeine because the fat in it will slow down digestion. Taking all these factors into account the results obtained gave a satisfactory connection between pulse rate and amount of caffeine consumed when we used coffee but not when we used coke. It may have been that we did not drink enough coke for it to be effective, and if we had repeated the experiment with a larger volume of say 250mls we may have had more conclusive results. ...read more.

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