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Modeling Blood Flow

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Grade Range
Group Size
2-4 students
Active Time
50 minutes
Total Time
50 minutes
Area of Science
Human Biology & Health
Key Concepts
Heart disease, Circulatory system, Atherosclerosis, Blood flow
Svenja Lohner, PhD, Science Buddies
Two plastic cups filled with red liquid sit in an aluminum pan


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.

Learning Objectives

NGSS Alignment

This lesson helps students prepare for these Next Generation Science Standards Performance Expectations:
This lesson focuses on these aspects of NGSS Three Dimensional Learning:

Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Science & Engineering Practices Asking Questions and Defining Problems. Ask questions about what would happen if a variable was changed.

Developing and Using Models. Develop and/or use models to describe and/or predict phenomena.

Use a model to test cause and effect relationships or interactions concerning the functioning of a natural or designed system.

Planning and Carrying Out Investigations. Make predictions about what would happen if a variable changed.

Engaging in Argument from Evidence. Use data to evaluate claims about cause and effect.
Disciplinary Core Ideas LS1.A: Structure and Function. Plants and animals have both internal and external structures that serve various functions in growth, survival, behavior, and reproduction.
Crosscutting Concepts Cause and Effect. Cause and effect relationships are routinely identified, tested, and used to explain change.

System and System Models. A system can be described in terms of its components and their interactions.


Aluminum pan, plastic cups, scissors, markers, measuring cup, water, stopwatch, tape and food coloring

Materials for teacher preparation:

Materials per group of 2–4 students:

Background Information for Teachers

This section contains a quick review for teachers of the science and concepts covered in this lesson.

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 as shown in Figure 1. 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.

Drawing of the human body with the circulatory system outlined in red and blue
Figure 1. The circulatory system of the human body.

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. This buildup is known as atherosclerosis. Over time, as the plaque grows thicker, the arteries become narrower, as shown in Figure 2. 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.

Drawing shows the cross-sections of a clear artery on top and a plaque filled artery on the bottom
Figure 2. Coronary heart disease can be caused by the buildup of plaque inside the arteries, which narrows their diameter and affects blood flow through our body.

In this lesson plan, students model what happens to blood flow when coronary heart disease narrows a person's arteries by comparing the flow of water (blood) through straws (arteries) of different diameters. The activity is also a great starting point for a variety of health discussions in the classroom.

Prep Work (15 minutes)

Engage (15 minutes)

Explore (20 minutes)

Reflect (15 minutes)


Make Career Connections

Lesson Plan Variations

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