Scientifc Method

Hypothesis: We believe caffeine does affect a persons’ blood pressure, because we know that Caffeine is a drug that is naturally produced in the leaves and seeds of many plants. It's also produced artificially and added to certain foods. Caffeine is defined as a drug because it stimulates the central nervous system, causing increased alertness. Caffeine gives most people a temporary energy boost. Which is lactated in tea, coffee, chocolate, many energy drinks.
Materials: The Materials we need to test this was
1. aneroid monitor
2. Chocolate
3. Pepsi soda
4. Tea
5. Coffee
Procedure: First we went to CVS for the Aneroid Monitor. We took our blood pressure before drinking or eating anything. Our Blood pressure at rest was 101 which says it normal. On the same day we ate a bar of chocolate waiting 44-45 minutes we check out blood pressure again it was 110. On the next day we drank one can o Pepsi soda, we checked out B.P (blood pressure) it went up to 114. On the day before that, we drank coffee and again we waited 45 minutes, we checked out B.P it was 118. And finally on the last day of our Experiment we Drank tea our B.P. was about 113.
We feel coffee had the most caffeine of them all.

Results:
At Rest--101
Coffee--118
Soda--114
Chocolate--110
Tea--113

These are then result we got about. As you can see Coffee seem to have a great affect on our blood pressure!

Resources

http://cchs-dl.slis.ua.edu/patientinfo/alcohol/caffeine.htm
http://www.wisegeek.com/what-is-caffeine.htm
http://www.mayoclinic.com/health/blood-pressure/AN00792
http://www.faqs.org/nutrition/Ca-De/Caffeine.html
http://www.cyh.com/HealthTopics/HealthTopicDetails.aspx?p=243&np=163&id=2155

Sources of caffeine

The richest sources of caffeine are tea, coffee, cola drinks, some over-the-counter medications, chocolate, and cocoa.
As little as 20 mgs of caffeine can produce noticeable body and mood changes. As a very rough guide to how much caffeine you may be taking on a daily basis...
An average cup of tea contains around 50 mgs of caffeine.
An average cup of instant coffee contains around 70-100 mgs. Instant decaffeinated coffee contains about 3 mgs.
A 6 oz cup of espresso coffee (much larger than the normal cafe cup, incidentally) contains about 80-90 mgs. A single-hit cappuccino will contain the same amount.
Filter coffee (called 'drip' in the US) can contain 25-50% more caffeine than instant.
A 340 ml or 12 oz can of regular or diet cola contains between 35 and 45 mgs. of caffeine depending on the brand
One ounce or 28 grams of chocolate contains about 10-15 mgs .
(An average cup is about 6 UK fluid ounces or 170 ml. Your precise intake of caffeine will, of course, vary with the strength of the drink. One person's mug of instant coffee might have 75 mgs while another person might prepare a 200 mgs hit! Useful link: CoffeeFAQ)

Caffeine video

To see a caffeine video please click on http://video.aol.com/video-detail/good-question-how-does-caffeine-work/4294411870. Thanx

Researchers

Researchers have attempted to find out how much caffeine people consume every day. Americans consume about 45 MILLION pounds of caffeine each year. In the United States, coffee drinkers drink an average of 2.6 cups per day. Total caffeine in for coffee drinkers was 363.5 mg per day - this includes caffeine from coffee AND other sources like soft drinks, food and drugs. Non-coffee drinkers even get plenty of caffeine: former coffee drinkers get about 107 mg per day and people who have never had coffee get about 91 mg per day. =)

The effects of Caffeine!

The main effect of caffeine is that it stimulates the central nervous system.With small amounts:
you feel more awake and alert,
your heart beats faster,
you can stay awake longer (if taken before you try to go to sleep),
you make more urine,
your hands shake slightly,
you have a smaller appetite.
With larger amounts, you may:become anxious and restless,have difficulty concentrating,get headaches,have difficulty getting to sleep,become confused.

Caffeine and exams

A small amount of caffeine, such as the caffeine in one cup of coffee or tea, seems to help many people to 'perform' better than having no caffeine. If people usually have a cup of tea or coffee to start the day, they do not manage so well if they miss that drink.
Large amounts of caffeine may make a person feel more awake, or stop them falling asleep, but they cannot study well or do exams better. In fact the anxious feelings due to the caffeine may make them do worse than usual.