# Ib Biology Ia

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• Published : January 20, 2013

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Sarah Clay
Internal Assessment

Design
Question: Does the caffeine in Coca-Cola affect blood pressure? Hypothesis: The amount of caffeine in Coca-Cola will cause to the adrenal glands, located on the top of the kidneys, to release more adrenaline which will in turn cause an increase in blood pressure. As the amount of Coca-Cola decreases, so will the difference between initial blood pressure and blood pressure after the consumption of the caffeine. Variables:

Independent Variables| Dependent Variables| Controlled Variables| Amount of Coca-Cola consumed for each trial: * 500mL * 400mL * 300mL * 200mL * 100mL| Blood Pressure after consumption of caffeine.| Blood Pressure pre-consumption of caffeine.|

Lab Setup:

Blood Pressure Cuff and BulbCoca-Cola

Measuring Cup

Vemier Labquest

Procedure: In order to test my hypothesis, I decided to use a common caffeinated beverage, Coca-Cola. The amount of caffeine in each bottle is given as 48mg/500mL. So, to keep my calculations clean my initial test was with 500mL of the Coca-Cola. I took my blood pressure with a Vermier Labquest before I consumed any caffeine to have a control variable. It was a manual blood pressure monitor, so I took my own blood pressure. After placing the cuff on my arm, I squeezed the bulb until the cuff pressure reached 170 mm Hg. Then, I released the bulb and let the pressure drop until it was 50 mm Hg and I used the release valve on the bulb to completely release the pressure and stopped the data collection. This data was recorded. Next, I measured the amount of the Coca-Cola used for the current test into a measuring cup and then consumed it. I waited 20 minutes after consumption to take my blood pressure again. Caffeine has been reported to take affect after a time period of 15-45 minutes. I did an identical test every day for five consecutive days with varying amounts of Coca-Cola consumed. On the first day, I consumed...