Science Buddies: "Ask an Expert"

I was wondering how I should go about this experiment?
What grade level would this experiment be appropriate for?
Is there anyway to make it more complicated or difficult?
If we were to test it on people how would we know it is the electrolytes affecting the blood pressure and not the caffeine or other ingredients?
Is this experiment original?


I will be doing this experiment with my friend and we have to have it done in 1 to 2 months or so.


Thanks for all you help.




Hi again,

I still do not understand how I would know if it is the caffeine/other ingredients affecting the blood pressure or the elctrolytes. What grade level would this experiment be appropriate for?

Also do you have any other ideas on experiment ideas. It has to be something to do with one thing affecting another. (Also nothing with plants) I know this is a very broad question but any help would be great with specific ideas/experiments.

Hi Cleo,

Welcome to Science Buddies! This is an interesting, but challenging idea for a science project.

Here is one project on blood pressure from the Science Buddies website that includes an idea for an experimental design.

https://www.sciencebuddies.org/science- ... p030.shtml

One of the difficulties of this type of experiment, as you have already realized, is that it’s difficult to design a perfectly controlled experiment. There are always uncontrolled parameters, like sugar, caffeine, time of day, etc. You might be able to evaluate these variables by designing a questionnaire to ask each test subject and testing each subject multiple times over a period of time. You would also need lots of volunteers for a project like this.

Please notice in the project outline that you will need informed consent from each participant or their parent if you will be including children in your experiment. Be sure and read the information on “Projects Involving Human Subjects,” in the procedure section of the experiment to make sure your project follows all of the rules.

Please post again if you have more questions. Good luck!

Donna Hardy

Hi again,

I still do not understand how I would know if it is the caffeine/other ingredients affecting the blood pressure or the elctrolytes. What grade level would this experiment be appropriate for?

Also do you have any other ideas on experiment ideas. It has to be something to do with one thing affecting another. (Also nothing with plants) I know this is a very broad question but any help would be great with specific ideas/experiments.

Hi Cleo,

That’s the problem. There are so many variables in blood pressure experiments that it’s difficult to control all parameters.

I think this project could be done at any grade level above 5th grade or higher. For high school, you would include more measurements and include statistical analysis of the results. For example, you might want have two individuals making each measurement and perhaps add a questionnaire to try to identify uncontrolled parameters.

I recommend that you click on “Science Fair Project Ideas,” at the top of this page and use the topic selection wizard to look for an alternate topic. You might decide that you want to proceed with the blood pressure experiment, or maybe find a project that is a little easier to control. For a science fair project, you need just one experiment with an independent variable that you can change, and an dependent variable that you can measure.

https://www.sciencebuddies.org/science- ... bles.shtml

Donna

Hi Cleo,

This is an interesting project idea and is appropriate for your level if you are still interested in doing it.

One thing that is known to affect blood pressure is the intake of water and/or electrolytes (ions dissolved in water). As you know, drinks like Vitamin Water and Gatorade have electrolytes that could affect blood pressure. One option is to modify the Science Buddies Electrolyte Challenge project to make it your own. The great thing about this project is that you can do it at home, and Science Buddies offers a kit that gives you all of the materials you need (https://www.sciencebuddies.org/science-f ... #materials). If you wanted to combine it with your original idea, you could see how the electrolyte content of different drinks correlates with blood pressure. For this, you would also need to purchase a sphygmomanometer (blood pressure cuff), in addition to the electrolyte kit.

You could pick a few different drinks for your test, and use the Electrolyte Challenge procedure (https://www.sciencebuddies.org/science-f ... #procedure) to determine the electrolyte content in each drink. Then you could have people drink the different drinks and look for an effect on their blood pressure. If you don't have time to do the Electrolyte Challenge portion of the experiment, you could just look at the effect of different drinks on blood pressure, as described below.

Let's say you chose 3 drinks to compare. For the experiments, you will want to take resting blood pressure prior to the drink, then ask the person to drink a set amount of liquid (which should be calculated as a fraction of their body weight, such as 10mL of liquid per kilogram of body weight). Then take their blood pressure at set intervals (say, every 30 minutes) for 2 hours after drinking the liquid. You should also have a control group that drinks no liquid, but still has blood pressure taken every 30 minutes for 2 hours.

Thus, you will have four groups: (1) no liquid, (2) water, (3) electrolyte drink #1, (4) electrolyte drink #2. In each group, you will take resting blood pressure, then have the person drink (or not), and repeat blood pressure measurements every 30 minutes for 2 hours thereafter. It will be important to get as many people to participate in your study as possible, so you have a large enough sample size to compare your groups statistically. Once you have the data, I can help you with the statistics.

You will not be able to control for other substances found in energy drinks (such as sugar and caffeine), but you can acknowledge that they, too, affect blood pressure. I think the measurements of the electrolytes will give you a more quantitative (numerical) way of interpreting your results.

As Donna said, the Science Buddies Topic Selection Wizard (https://www.sciencebuddies.org/science- ... gister.php) can help you find another project if you no longer wish to pursue your original idea.

Let us know if you need more help along the way!

Heather