Science Buddies: "Ask an Expert"

Hello ScienceBuddies Mentors,

I am planning on doing the science buddies cardiovascular project which determines the effect of reduced artery sizes on blood flow rate, and was wondering if there was any way I could add some variation to my project? Maybe measuring the effect of viscosity on blood flow rate, and etc.? Secondly, the project only adds two measurements for the valves, 3/8 and 1/4. How do I come up with more specific sizes? Is there a reason behind the 3/8 and 1/4 that I need to be aware of in order to come up with more measurements? Third, is there any other liquid that can be used to accurately model blood? Thank you so much.



[Administrator note: Project: https://www.sciencebuddies.org/science- ... -flow-rate]

Sounds like a fun project! The reason for the specific valve measurements is because these are the sizes of valves and tubing that are commonly available at your hardware store. If you are able to find other sizes it could be a good thing to test. For testing larger tubing, be careful when drilling the larger hole in the bucket. You may also need to change your measurement to how long it takes to fill a measuring cup to 1 cup instead of 1/2 cup because the larger tubing could fill 1/2 cup too quickly to easily measure the time. If you change your measurement to 1 cup, be sure to do the same for all tubing sizes.

If you'd like to test another variable besides tubing diameter you might consider viscosity of the fluid as well as what is called "static head." Be sure to only change one variable at a time.
- Viscosity of the fluid affects flow rate as described by "Poiseuille's law."
- You might also try experimenting with different starting heights of water in the bucket. More water in the bucket when you start the experiment would provide more "static head" or "head pressure" on the tubing and therefore effect the flow rate. While this particular variable doesn't necessarily apply to a cardiovascular system, it would be an interesting variable to test in your apparatus.

Good luck!

Audrey

Hello!

Sciencebuddies published a project on making fake blood here: https://www.scientificamerican.com/arti ... cientific/ which should help on getting more realistic results!

Good luck and feel free to ask any other questions you might have!

-Regina V.