Jump to main content

Summary

Active Time
30-45 minutes
Total Project Time
30-45 minutes
Key Concepts
Health, heart disease
Credits
Svenja Lohner, PhD, Science Buddies
Model Your Blood Flow – STEM activity

Introduction

Why is it important to eat healthy and exercise? If you don't, you might end up with a cardiovascular disease. These diseases are conditions that affect your heart and blood vessels. The job of your cardiovascular system is to transport blood through your heart, veins, and arteries, to provide oxygen and nutrients to your body. If this blood flow doesn't work properly anymore, it can have serious consequences. In this activity, you will find out what happens to the blood flow of people that have a condition called coronary heart disease.

This activity is not recommended for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.

Materials

  • Plastic cups, 16 oz. (2)
  • Two straws with different diameters (a 2-inch piece of each)
  • Modeling clay
  • Stopwatch
  • Tray (big enough to fit 500 mL of water)
  • Water
  • Red food coloring
  • Measuring cup
  • Scissors
  • Permanent marker
  • Paper

Prep Work

  1. Add 400 mL of water and mark the water level on the outside of one of the 16 oz. plastic cups using a permanent marker. Then, make a mark on the other 16 oz. cup at the same height.
  2. Poke a hole into the sides of both cups, about one inch from the bottom. Widen the hole enough to comfortably fit each straw.

  3. Cut the straws to approximately 2-inch lengths.
    Think about:
    What do you think the straws represent in your blood flow model?
  4. Insert the straws into the holes. Make sure they are not squeezed. The straws should point down on the outside of the cup so water can flow out easily.
  5. Use modeling clay to seal the inside and outside of the hole around the straw.

  6. Prepare one liter of water. Add red food coloring to the water.
    Think about:
    What does the red water represent in your blood flow model?

Instructions

  1. Start by placing the cup with the wide straw into the tray.
    Think about:
    What condition does the cup with the wide straw represent in your model— a healthy or unhealthy cardiovascular system? Can you explain why?
  2. Then seal the end of the wider straw with a piece of modeling clay.

  3. Fill the cup up to the mark with red water. Improve the clay seal if needed.
  4. Remove the clay seal from the end of the straw and immediately start the stopwatch. Stop the stopwatch when the water stops flowing through the straw.
    Think about:
    How long does it take until the water stops flowing out of the cup?
    Record the time on a piece of paper.

  5. Place the cup with the narrow straw into the tray.
    Think about:
    What condition does the cup with the narrow straw represent? Why do you think this is the case?
  6. Seal the end of the narrow straw with a piece of modeling clay.
  7. Fill the cup with the narrow straw up to the mark with red water. Again, improve the clay seal if needed.
  8. Then remove the clay seal from the end of the straw and again start the stopwatch as soon as the water starts flowing. Stop the stopwatch when the water stops flowing. Record the time on a piece of paper.
    Think about:
    How long did it take this time until the water stopped flowing?
  9. Compare both times that you recorded on your paper.
    Think about:
    Which condition (wide or narrow straw) resulted in a faster and better blood flow? What does your result say about the blood flow in people with coronary heart disease (atherosclerosis)?

Cleanup

Pour the red water into the sink. Dispose of the cups and the straws in the trash. You can dry your modeling clay and reuse it.

What Happened?

You probably guessed right that the straws in your blood flow model represent the arteries in your body that transport blood from your heart to your organs. The red water in your model is the blood that flows through the arteries. Testing the setup with the wide straw simulates a healthy cardiovascular system in which the arteries are free from any plaque. As you should have noticed, the 'blood flow' out of the cup should have been relatively fast. The second setup with the narrow straw represents an unhealthy cardiovascular system. The artery (straw) is starting to get clogged with plaque and thus the diameter of the artery gets smaller and smaller. This also means that less blood can flow within the artery, which you should have observed in your experiment. With the narrower straw, the water takes much longer to flow out of the cup. In the worst case during coronary artery disease, the whole artery can get clogged and no blood can flow to your organs anymore. So, better eat healthy and exercise to keep your blood flowing!

Digging Deeper

To be healthy, every part of the human body needs to be supplied with oxygen and nutrients. The job of blood is to transport oxygen and nutrients by traveling through the body's circulatory system, also called the cardiovascular system (heart, veins, and arteries) and delivering them to the other parts of the body. The heart acts as a powerful pump that generates the force necessary to move the blood around the circulatory system. When something goes wrong with the body's circulatory system, it can lead to serious health consequences, including death.

The most common problem with the circulatory system is coronary heart disease, also called coronary artery disease. Coronary heart disease is caused by the buildup of cholesterol and other material, called plaque, in the arteries: the blood vessels that carry oxygenated blood from the heart to the organs. The heart disease that is caused by this buildup is known as atherosclerosis. Over time, as the plaque grows thicker, the arteries become narrower. As the arteries narrow, they cannot carry as much blood to the organs. The decrease in oxygenated blood can lead to chest pains and heart attacks. The plaque sometimes becomes dislodged and forms blood clots that block the blood flow, which can also cause heart attacks and strokes.

icon scientific method

Ask an Expert

Curious about the science? Post your question for our scientists.

For Further Exploration

  • Calculate the flow rates of the 'blood' in both of your setups (wide and narrow straw) by dividing the water volume in mL at the beginning by the time it took for the water to flow out of the cup. How do both numbers compare?
  • Instead of using to different-sized straws, use two identical straws. Then use modeling clay to 'clog' on of the straws to actually model the plaque buildup inside an artery.

Project Ideas

    Science Fair Project Idea
    Your heart starts beating before you are born and keeps right on going through your whole life. Over an average lifetime, the human heart beats more than 2.5 billion times. Keeping your heart healthy means eating right, not smoking, and getting regular exercise. Which of your favorite physical activities give your heart the best workout and help keep it fit? In this science project, you will use a smartphone equipped with a sensor app to visualize your heart rate and find out which… Read more
    Science Fair Project Idea
    Over an average lifetime, the human heart beats more than 2.5 billion times, supplying blood to the entire body. When a person exercises, the heart has to work harder than usual. Have you ever wondered how quickly your heart beats when you exercise, or how long it takes to recover back to its normal rate after you are done exercising? Is the heart rate recovery time faster for people who get regular exercise compared to people who do not? Try out this science project to find out! Read more

Activities

    STEM Activity
    1
    2
    3
    4
    5
    6 reviews
    Have you ever wondered what happens to the heart as we exercise intensely? How does its beating change? A doctor can figure this out by using a tool called a stethoscope, which is a long, thin plastic tube that has a small disc on one end and earpieces on the other end. In this activity, you will make a homemade stethoscope and use it to measure peoples' heart rates at rest and after exercising. Read more

Lesson Plans

    Lesson Plan Grade: 4th
    1
    2
    3
    4
    5
    1 review
    In this fun, hands-on lesson, students explore their heartbeats and learn about blood circulation. They will make their own stethoscopes, use them to measure their heart rates and investigate how heart rate is affected by exercise. Read more
    NGSS Performance Expectations:
    • 4-LS1-1. Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.
    Lesson Plan Grade: 4th
    1
    2
    3
    4
    5
    1 review
    Why is it important to eat healthy and exercise? In this hands-on lesson plan, students will build a simple model to explore the effects of plaque buildup in arteries. The model allows them to demonstrate what happens to blood flow when heart disease narrows a person's arteries. Read more
    NGSS Performance Expectations:
    • 4-LS1-1. Construct an argument that plants and animals have internal and external structures that function to support survival, growth, behavior, and reproduction.

Links

Careers

Career Profile
Shakespeare described humans as a "piece of work," and others have called the body "the most beautiful machine," but like any machine, sometimes body parts need repairs or servicing when the body cannot take care of the problems itself. That's where biomedical engineers come in. They use engineering to solve problems in medicine, such as creating replacement body parts, drug-delivery systems, medical instruments, and test equipment. Their work helps restore health and function, and improves the… Read more
Career Profile
The first leading cause of death in the United States is heart disease, and the third leading cause is stroke. Cardiovascular technologists or technicians are key members of the healthcare teams that are on the front lines of treating heart and blood vessel diseases and conditions. They set up monitors and tests to help physicians diagnose heart or blood vessel problems. Then they work with physicians to treat an identified problem. For example, they might help break up a blockage in an artery… Read more
Career Profile
Hematologists are all about blood. They diagnose people with blood disorders and prescribe or administer appropriate treatments. There are many different types of blood disorders, including bleeding disorders and blood cancers. Hematologists also investigate ways to improve diagnosing and treatment of these disorders. Read more
Career Profile
Emergency medical technicians and paramedics belong to a group of healthcare workers known as first responders. They are among the first people to respond to an accident or emergency, providing prehospital care for conditions such as heart attacks, strokes, gunshot wounds, childbirth, or falls. Although this work is physically and emotionally demanding, many emergency medical technicians and paramedics enjoy the challenges and the satisfaction of knowing their work is critical in saving lives. Read more

Reviews


|
Science Buddies |
Was this review helpful?

Be the first one to review this activity.
Top
Free science fair projects.