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19 Science Lessons About Human Body Systems

Use these free STEM lessons and activities to help students get hands-on modeling, testing, and exploring the science of the human body and its interconnected systems.

Tongue dyed blue to count papillae, blood flow model, and student doing an eye activity that results in an optical illusion to represent collection of STEM lessons and activities to teach about the Human Body and Its Systems

The free STEM lessons and activities below help educators teach students about human body systems, with a focus on the circulatory and cardiovascular systems that helps keep blood pumping through the body, the respiratory system that continuously makes oxygen available to the body and removes carbon dioxide, the nervous system that sends messages throughout the body, and the immune system that helps the body respond to pathogens. There are many other human body systems, too, including the digestive, reproductive, endocrine, skeletal, muscular, lymphatic, integumentary, and urinary systems!

In these NGSS-aligned STEM lessons and science experiments, students will learn fundamental information about the human body and will model bodily systems to better understand issues like coronary artery disease, autoimmune diseases, the ways in which vaccines work in the body, how we breathe, how the body creates energy, the role cellular respiration plays, and the importance of healthy eating and exercise. As part of these lessons, students will also investigate and observe the interconnectedness of bodily systems. Deficiency or a problem in one system will often have implications for other systems.

The resources below have been grouped as follows:

Note: for more information about the various "types" of resources available, see Understanding Science Buddies' Resources.

Lesson Plans and Activities to Teach About the Human Body and Its Systems

Circulatory and Cardiovascular Systems

  1. 1. Heart Rate Science

    The human heart beats constantly as it continuously pumps blood throughout the body. It circulates the body's blood approximately three times a minute! To keep the heart working properly, doctors recommend individuals exercise regularly, during which they raise their heart rate to its target rate. In the Sweaty Science: How Does Heart Rate Change with Exercise? activity, students do various exercises and monitor their heart rate (by taking their pulse) to explore the relationship between exercise and heart rate. Note: For a related experiment, see the Heart Health: How Does Heart Rate Change with Exercise? project. In this experiment, students use a mobile phone app to help visualize their pulse at rest and after exercise. Questions: Is there a maximum heart rate? How is it calculated? How long does it take for a person's heart rate to return to normal after exercise? What is this called? Why is exercise important for cardiovascular (heart) health?

    Young person taking radial pulse, fingers on wrist

  2. 2. Explore Heart Rate with a Homemade Stethoscope

    In the Measuring Heart Rate with Your Own Stethoscope lesson, students make stethoscopes and then use them to measure their heart rates and investigate how heart rate is affected by exercise. Questions: How does a stethoscope allow us to hear our heart rate? How can we effectively measure our heart rate (or pulse)? (Note: for a related shorter activity, see Make Your Own Stethoscope. In this activity, students explore the design and science behind how a stethoscope works.)

    Homeade stethoscope behing used by one student to listen to the heart beat of another student

  3. 3. Model Blood Flow

    Eating healthy and getting regular exercise are important for the heart and can help reduce the buildup of plaque in the arteries. In the Modeling Blood Flow lesson, students build a simple model to explore the way the heart pumps blood through the arteries. This model helps them see what happens when plaque builds up and the arteries narrow. Questions: What role do the arteries play in the circulatory system? What happens to the arteries when plaque accumulates in them? How can plaque buildup be prevented? (Note: The video shown below is part of the related Model Your Blood Flow activity, which involves a similar model of blood flow.)

    Model Your Blood Flow – STEM activity

  4. 4. Where Would a Vampire Bite You?

    In the Circulatory System: Where Would a Vampire Bite You? video lesson, fourth-grade students explore the circulatory system using a self-paced video lesson format. After learning about types of blood vessels, they are guided in building and using a simple model to investigate blood flow in different types of blood vessels.

    Dish lined with aluminum foil with a plastic cup in it that has a hole and a straw to model blood flow through an artery

  5. 5. Heart Valve

    In the Saving a Life: Heart Valve Replacement lesson, students learn about heart valves and then design a prototype that could be used for mitral valve replacement. Questions: What types of materials can be used for artificial heart valves? What are the pros and cons of these different approaches to valve replacement? How long does a replacement valve last?

    Saving a Life: Heart Valve Replacement

Respiratory System

  1. 6. How We Breathe

    In the Why and How do We Breathe? lesson, students learn about the respiratory system and make a model of the human lung to explore how we breathe. Questions: Do all animals breathe the same way? What might explain the evolution of the human lung?

    Make a Lung Model – STEM activity

  2. 7. Model a sick Lung

    In the Explore How Lung Infection Influences Breathing activity, students make a model of a sick lung using a bottle and balloon. The model helps demonstrate how lungs or airways filled with mucus affect breathing. Questions: What causes mucus to build up in the lungs? What happens when excess mucus is present in the lungs or airways?

    Model a Lung Infection

  3. 8. How Systems are Connected

    In the Cell Organization in the Human Body experiment, students explore the interconnectedness of bodily systems. Using anemia, as an example, students investigate to find out how iron deficiency anemia is related to numerous systems in the body. How is anemia related to a problem like shortness of breath? The connection may not be immediately obvious to students. In the lesson, they observe that red blood cells carry oxygen from the lungs, but the amount of oxygen red blood cells can pick up is related to the amount of hemoglobin (a protein) they have. Sufficient iron is necessary to make hemoglobin. Question: What other bodily systems are related to the respiratory system?

    Explore How we Breathe

  4. 9. Cellular Respiration

    The lungs are responsible for passing oxygen to the cells to circulate throughout the body. The lungs also rid the body of carbon dioxide that is created during cellular respiration. In the Get Energized with Cellular Respiration! lesson, students learn about cellular respiration and its relationship to energy. They then investigate how the amount of carbon dioxide (C02) they exhale changes during exercise. To measure C02, students use a simple colorimetric reaction that can be easily assessed visually. When they blow into a straw, the color the liquid in the cup turns indicates whether there is more or less carbon dioxide present. Questions: Why is it important for the body to get rid of carbon dioxide? Why does the amount of carbon dioxide change during exercise?

    Diagram and image showing the setup for experiment with cup with colored water, covered top, and straw
    Cellular Respiration Introduction

Nervous System and Senses

The nervous system sends messages throughout the body and helps systems communicate with one another. It also helps you react and respond to changes both inside the body and in the world around you. Your senses—including taste, touch, hearing, vision, and smell—are part of the nervous system and allow your body to respond to information from related sensory organs (e.g., tongue, skin, ears, eyes, and nose).

  1. 10. How Fast Can You React?

    In the Think Fast! Measure Your Reaction Time! activity, students use a simple test to see how quickly individuals can "react" to an object being dropped and catch it. The reaction time for this test is related to the eyes perceiving that the object has been dropped and the nervous system then instructing the fingers to close to catch the object. All of this happens very quickly! But reaction times vary, and as students discover in the activity, changes in the environment can make a difference. Questions: Why does lowering the light affect the reaction time for many volunteers? What variables about a person may influence reaction time?

    Hand ready to grab a ruler being dropped

  2. 11. Fool Your Vision

    In the Fool Your Vision to Find Out How It Works lesson, students learn how human vision works and experiment with two fun optical illusions. Sometimes the brain "gets it wrong" and is tricked into thinking it perceives something that isn't really there. By the end of this lesson, students will be able to explain why the optical illusions in the lesson make them think they see a hole in their hand or colors that aren't actually there. Questions: What are afterimages? What is sensory receptor fatigue? What does it mean to have a dominant eye?

    Student holding a cardboard tube to one eye and looking at the other hand for an optical illusion demonstration

  3. 12. Stroop Effect

    You know the color of the ink is blue, but the word written in that color says red. What color will you say out loud when asked to say the color of the ink? That's the puzzle of the Stroop effect, a fascinating brain phenomenon first described by John Ridley Stroop in 1935. When the written word is a color and is a different color than the ink, people's reaction time changes. The Seeing Science: Exploring Perception with the Stroop Effect activity guides students in testing themselves and classmates or others to see how their timing compares when naming colors when the text and ink matches and when it doesn't. Can they master their brains and beat the Stroop effect? Questions: How is the Stroop effect similar to the challenge of patting your head and rubbing your stomach at the same time? How does the concept of "interference" (or the interference effect) help explain what happens with the Stroop effect?

    Flash cards set up with colored inks and names of colors for Stroop effect test

  4. 13. Are You a Supertaster?

    Have you heard some people described as having a "refined palate"? These people may be able to detect small changes or specific ingredients in recipes. Whether a person has this ability or not is related to the number of taste buds the person has. In the Do You Love the Taste of Food? Find Out if You Are a Supertaster! activity, students put their taste buds to the test, or at least to the count. Taste buds are contained by the papillae, the small bumps on the tongue, and the number of papillae varies from person to person. Some people have more papillae, and some have less. People who have more than the average number of taste buds may be supertasters. These individuals experience flavors more strongly and may find some foods (like broccoli, cabbage, and spinach) especially bitter. On the other end of the papillae spectrum, non-tasters have fewer taste buds and may find many foods bland overall. With a simple experiment, students can count the number of papillae on their tongues and see how their number compares to how they think they experience food. Are they supertasters? A simple swab of food coloring on the tongue and an office supply paper reinforcement circle helps students isolate a section of the tongue and count the papillae. Tip! Snapping close photos of the section of the tongue to be counted for each student may be helpful. Questions: Is the number of papillae a person has inherited?

    Student with tongue died blue and a paper disc helping show the papillae

  5. 14. The Shape of Ears

    In the Ears: Do design, size and shape matter? activity, students explore the relationship between the size and shape of ears and hearing. The part of the ear that sticks out from our heads (the pinna or auricle) helps direct sound waves in the air into the ear canal to the eardrum (tympanum), which has a membrane that vibrates in response to sound waves. Sound waves are ultimately converted to electrical signals that are passed to the brain where they are interpreted as sound. Do bigger ears mean better hearing? Students design, make, and test hearing devices to attach to their own ears to see how size and shape of the external ear affect hearing. Questions: What are the major parts of the human ear? What role do the pinnae play in hearing?

    Student with two homemade hearing devices made from paper plates

  6. 15. Your Nose Remembers

    When odor molecules in the air reach smell receptors in our noses, signals are sent to the brain to identify the smell. Humans can differentiate more than one trillion different scents, but how easily we are able to detect a smell partly depends on how many odor molecules are present. Have you ever gotten just a "whiff" of a smell but not quite enough to be sure of what you were smelling? In the Play a Memory Game with Your Nose! activity, students put their noses to the test with a smelling game to see if they can differentiate and identify four common food flavorings. Questions: What causes odor molecules? What happens to our ability to distinguish smells when odor molecules are combined with water? How does the human olfactory system compare to other animals?

    Student measuring vanilla flavoring into a small plastic cup for smell memory experiment

Immune System

  1. 16. Body Temperature

    What if your temperature isn't 98.6°F (37°C)? In the What Is Normal Body Temperature for Humans? activity, students explore the range of normal human body temperature and how body temperature is related to homeostasis in the body. Questions: Why is the average normal body temperature lower today than it may have been a hundred years ago? How much of a change in body temperature is involved in hypothermia or hyperthermia?

    Student having her temperature taken using a thermometer in the ear

  2. 17. Immune System

    In the Fighting Infections with Your Immune System lesson, students learn about the immune system and how it works to fight pathogens that make us sick. Using a model of the immune system, students explore how the immune system responds to invading bacteria or viruses. What happens when model antibodies (created with magnetic tape, twist ties, and plastic wrap) come into contact with pathogens (represented by iron filings)? Questions: What is the difference between a primary immune response and a secondary immune response? What are memory cells and how do they help the body respond to pathogens they have encountered before? What is the relationship between memory cells, vaccines, and immunity to a pathogen? What is an autoimmune disease?

    Model antibodies made with plastic wrap and magnetic tape in a jar of salt and iron filings to represent human body, cells, and pathogens

  3. 18. When the Body Attacks Itself

    Some diseases are caused by pathogens that attack the body, but other diseases are caused by the body mistakenly viewing normal cells as foreign and destroying them. In the Model the Chances of Getting an Autoimmune Disease lesson, students learn about autoimmune diseases. They then do an activity with dice and candies to model the probability of developing an autoimmune disease like Type 1 diabetes, celiac disease, rheumatoid arthritis, or lupus. Questions: What does the fact that autoimmune diseases exist tell us about the human immune system?

    Bowl, die, and bag of candies uses for autoimmune disease probability activity
    Note Many autoimmune diseases have a genetic component. For additional lessons to teach about genetics, see the Teach Genetics and Heredity with Free STEM Lessons & Activities collection.
  4. 19. Creating Immunity with Vaccines

    In the Using Vaccines to Fight Outbreaks lesson, students learn how vaccines work with the immune system to create immunity in individuals. Using SimPandemic, a free online tool, students can model different vaccine parameters to investigate the role vaccines play in stopping the spread of a virus or ending a pandemic. Questions: Can vaccines prevent outbreaks? What is the role of a vaccine in helping protect a population during an outbreak? How are vaccines developed and tested?

    Vaccine being injected into arm


The following word bank contains words that may be covered when teaching about XX using the lessons and activities in this resource.

  • Anemia
  • Antibodies
  • Artery
  • Autoimmune disease
  • Blood
  • Carbon dioxide
  • Cardiovascular system
  • Carotid pulse
  • Cellular respiration
  • Circulatory system
  • Digestive system
  • Endocrine system
  • Exercise
  • Fever
  • Hearing
  • Heart
  • Heart rate
  • Heart valve
  • Hemoglobin
  • Homeostasis
  • Hyperthermia
  • Hypothermia
  • Immune system
  • Immunity
  • Integumentary system
  • Lung
  • Lymphatic system
  • Memory cells
  • Mucus
  • Muscular system
  • Nervous system
  • Olfactory system
  • Oxygen
  • Papillae
  • Pathogens
  • Pulse
  • Radial pulse
  • Red blood cells
  • Reproductive system
  • Respiratory system
  • Senses
  • Sensory organs
  • Skeletal system
  • Stethoscope
  • Supertaster
  • Smell
  • Target heart rate
  • Taste
  • Temperature
  • Touch
  • Urinary system
  • Vaccine
  • White blood cells

Thematic Collections

Collections like this help educators find themed activities in a specific subject area or discover activities and lessons that meet a curriculum need. We hope these collections make it convenient for teachers to browse related lessons and activities. For other collections, see the Teaching Science Units and Thematic Collections lists. We encourage you to browse the complete STEM Activities for Kids and Lesson Plans areas, too. Filters are available to help you narrow your search.

Understanding Science Buddies' STEM Resources

Lesson Plans contain materials to support educators leading hands-on STEM learning with students. Lesson Plans offer NGSS alignment, contain background materials to boost teacher confidence, even in areas that may be new to them, and include supplemental resources like worksheets, videos, discussion questions, and assessment materials.

Video Lessons include NGSS alignment and offer a plug-and-play option for teaching a STEM lesson. Each Video Lesson asks a science question, teaches students about the relevant science, and guides students in a hands-on experiment that will help them answer the question. Video Lessons are NGSS-aligned and bring core science concepts to life with storytelling, animation, and photos using a self-paced engage, explore, and reflect format.

Activities are simplified explorations that can be used in the classroom or in informal learning environments.

Projects are written to support students doing independent science projects or science fair projects. Projects can be adapted for classroom use.

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