Our experiment today has less to do with coffee and more to do with the effects of caffeine on the body. In our activity, you will create an experiment to see the difference in effects between caffeinated and decaffeinated coffee on a variety of test subjects. Before we start that, let’s learn a little more about caffeine and what a stimulant does.
Caffeine is classified as a legal stimulant that appears in many beverages and foods that we consume. Check out the links below for information about how caffeine affects those who consume it.
What is a stimulant?
A stimulant is “a substance that raises levels of physiological or nervous activity in the body.” This means that stimulants make you more alert and energized, but also raises your heart rate and blood pressure.
How is coffee decaffeinated?
Decaf coffee doesn’t come from different “special” coffee beans. Normal coffee beans go through a decaffeination process in which steam or water is added that causes the bean to swell. This swelling allows for caffeine to be extracted. Read more in the link below.
Some people even say that caffeine can increase athletic performance! According to several sources such as
Runner's World, having caffeine before a workout can reduce an athlete's perceived exertion. Basically, you don't feel as tired. If you do take caffeine before working out, just make sure to also stay hydrated!
YOU WILL NEED:
- A minimum of 10 test subjects
- Regular coffee
- Decaf coffee
- Coffee maker
- Styrofoam coffee cups
Here’s what to do!
Learn how to take a pulse. Check out the image below for instruction. Practice taking a pulse a few times before starting your experiment.
1. Find your artery on your wrist, right below your thumb.
2. Place two fingers of one hand over the other artery, as pictured above. (Do NOT use your thumb, as it has its own pulse.
3. Count the beats for 10 seconds, then multiply by 6 to get the beats per minute.
Now you can get started on your experiment!
- Gather 10 test subjects. A higher number is always better to get more accurate results, so if you can get more participants, go ahead! When you ask your subjects to participate, make sure you tell them to refrain from eating or drinking for two hours before the test. Why do you think this would matter?
- Write your test subjects’ names on small slips of paper. Fold the slips and put them in a bag.
- Draw out five names. These five will receive regular coffee.
- Draw out the last five names. These five will receive decaf coffee. They are receiving a placebo. This means that they think they are receiving the regular treatment, which is normal caffeinated coffee, but they are really receiving decaffeinated coffee. Make sure you do not tell your participants whether they are receiving regular or decaf!
- Write your test subjects’ names on the coffee cups.
- Brew a pot of decaf coffee and pour it into the cups of the last five names you drew.
- Brew a pot of regular coffee and pour it into the cups of the first five names you drew.
- Now it’s time for testing!
- Before you test your subject’s pulse, ask them about their normal caffeine consumption. Take notes on their response. Take your subject’s pulse before you give them any coffee. Write down the result.
- Give your subject the coffee. Take their pulse 5, 10, and 15 minutes after drinking the coffee.
- Move on to the next subject and repeat steps 9 and 10 until you are finished with all 10 participants.
- Graph the pulse for each participant. The X-axis should be time and the Y-axis should be pulse.
- Analyze your results. Trace your graphs for caffeinated coffee participants in green. Trace your graphs for decaffeinated coffee participants in red. Do the green graphs look different than the red ones? What does this tell you about caffeine’s effect on the body?
- Look at the graphs again and trace the regular caffeine consumers in blue. Do these graphs look different from those who are not regular caffeine consumers? Did caffeine affect non-users more so than regular users?
- How else could you test caffeine? Example: Have runners who regularly use caffeine run a mile without caffeine and record their time, pulse, and perceived exertion. The next day, repeat the process with the same subjects after they drink a cup of coffee. Does the coffee make a difference?
https://upload.wikimedia.org/wikipedia/commons/thumb/4/45/A_small_cup_of_coffee.JPG/800px-A_small_cup_of_coffee.JPG File used in accordance with the
Creative Commons Attribution 2.0 Generic License. Image was not changed.
Jynto, 2011. Caffeine (1) 3D ball.
https://upload.wikimedia.org/wikipedia/commons/thumb/0/05/Caffeine_%281%29_3D_ball.png/800px-Caffeine_%281%29_3D_ball.png File in the Public Domain.
Haggstrom, M., 2012.
https://upload.wikimedia.org/wikipedia/commons/thumb/0/07/Health_effects_of_caffeine.svg/800px-Health_effects_of_caffeine.svg.png File in the Public Domain.
Pulse photo and running photo provided by Maddie Van Beek.