Equipment
This is the equipment we will use.
- Coca Cola
- Non Caffeine Coca Cola
- Red Bull
- Plastic cup
- Stop Clock
A Fair test
We will make this investigation fair by.
- Drinking exactly the same amounts of each drink.
- Make sure that it is the same person who is drinking the drinks.
- After every drink sit still until your pulse is back to resting pulse rate which is 60-70 beats per minute (bpm).
- Take at least five readings for each drink and we will take the readings every minute.
Method (Plan)
This is what we will do in the experiment.
- Collect a plastic cup and pour 250ml of Coke A into it.
- Measure your resting pulse rate for one minute.
- Write your resting pulse rate down and drink the first drink.
- Straight after drinking the drink start the stop clock and measure your pulse rate for one minute.
- After one minute write your pulse rate down and record your pulse rate for another minute.
- Repeat step 5 until you have at least five readings.
- When you have five readings sit still wait for about ten minutes until you pulse rate is back to resting rate.
- After each drink rinse out your plastic cup and make sure there is nothing in it for example any left over coke.
- When back to resting pulse rate do exactly the same for Coke B and Red Bull.
Obtaining evidence
Results
Here are the results that were produced from my experiment
Analysis
Results
My results show that when I drank Coke A my heart rate increased rapidly up to 118bpm to start of with but then decreased back down to 65bpm. Then my heart rate started to go all over the place as it increased then decreased then increased and so on between 60bpm and 80bpm. This was unusual as my heart rate should have kept on increasing throughout the 10 minutes. The repeat of Coke A was much better but still did not increase and increase as time went on. My heart rate started at 70bpm and during the 8 minutes of taking readings my heart rate stayed between 60bpm and 70bpm. This is quite good because I was a bit worried with the first one as it went quite wrong. I would probably have to do coke A again to get the right results.
My results show that when I drank Coke B my heart rate started to increase until a certain point and then came down and stayed around that point until it jumped up again then back down to a constant position. When I repeated Coke B I got more of a smoother line just like a wave as it increased then decreased around 95bpm.
My results show that when I drank Red Bull my heart rate stayed around the same point as it stayed between 85bpm and 95bpm. The line I got from the results is again quite smooth, which shows that my heart didn’t jerk up and increase or decrease rapidly. I didn’t have time to do a repeat of Red Bull but if I did I would predict that the line would have been even smoother than the first one because in all of my repeats the line seemed to become more accurate and straighter. I think this for each of the first drinks my body was not used to them but as I did a repeat my body got used to them and the line became straighter.
Conclusion
I conclude that by looking at my results that if you drink normal coke, Diet Coke or Red Bull your heart rate only changes the slightest bit. These answers are wrong as my heartbeat should increase after drinking the normal Coke and stay the same after drinking Diet Coke. There is a small pattern in my results and I think there are, every time I did a repeat the line was more accurate. My results did not support my prediction as I predicted that the normal Coca Cola and the Red Bull energy drink would speed my heartbeat up but the Non Caffeine Coca Cola would not. But When I drank Coca-Cola A and Red Bull my heart rate seemed to go up then down then up and then down again. The same happened with Coca-Cola B, where my heart rate was supposed to stay the same, it increased then went down then up and then down. I don’t know why this happened and these results have puzzled me. I would have to do the experiment again to see what I did wrong and to see if I could get more accurate answers.
Evaluation
I think the experiment went quite well but it could have been done better as the results that were produced are not correct. I know this because my findings did not support my conclusion. I think that my readings were not very good because I could have had a drink of something with caffeine in it before doing the experiment or I was not sat still enough and my heart rate increased because of that. I also might have laughed during the experiment, this will have increase my heart rate and made the experiment unfair and less accurate.
My results are quite accurate as the points around the line of best fit are quite close and this makes the graphs look good. Although my readings are quite close to the line of best fit my heart rate did not increase as it was supposed to. These results could be better because they could have increased or stay the same as my heart should have. If I wanted to get more accurate results I would have to do the experiment again.
Anomalous results
On Coke A I hade one major anomalous result and a couple just outside 10bpm off the line of best fit. The major anomalous result is between 50bpm and 60bpm out of the line of best fit. I think that this anomalous result is anomalous because it was the first pulse rate of the first drink of the first day of the experiment and the others were not as anomalous because I was not used to all of the coke until later on. Also I was a bit nervous before the experiment so that could have made the result anomalous and really high.
I have some evidence to support my conclusion and you will find this evidence by looking at my graphs. This shows everything that I have said in my conclusion
Improvements
To improve the reliability of my results I shall.
- Not drink anything before the experiment
- Don’t laugh during the experiment
- Sit still after drinking the drinks
- Time my pulse rate exactly to one minute. No more, no less
