Teacher sheet · Ages 10–11 · about 45–50 minutes
How breathing works
Lesson page: echoesof.science/school/heart-and-lungs/ages-10-11/ · Pupil worksheet: echoesof.science/school/heart-and-lungs/ages-10-11/print/
Learning aims
- Describe the path of air into the lungs.
- Explain how the diaphragm makes us breathe.
- Describe gas exchange in the alveoli.
- Describe the heart as a four-chambered double pump with valves.
Lesson plan
| Time | Activity |
|---|---|
| 5 min | Starter: take a deep breath with a hand on your belly. What moves? |
| 10 min | Read the text; trace the air path on a diagram. |
| 20 min | Build the model lung in groups. |
| 5 min | Game: Follow the path. |
| 5 min | Quiz. |
Materials for the experiment
- A clear plastic bottle (about 1.5 L), bottom cut off by an adult
- Two balloons
- A drinking straw (or a Y-shaped tube)
- Modelling clay or Blu-Tack
- Sticky tape
- Scissors (adult only)
Safety: Only an adult cuts the bottle; cover the cut edge with tape. Anyone with a latex allergy uses latex-free balloons or watches. Don't put balloons or bits of balloon in your mouth.
Common misconceptions
| Pupils may think… | Actually… |
|---|---|
| We breathe in pure oxygen and breathe out pure carbon dioxide. | Air is mostly nitrogen; we take some oxygen out and add some carbon dioxide. |
| The lungs suck air in by themselves. | The diaphragm and chest muscles make the space; the lungs fill as a result. |
| Blood in veins is blue. | It is darker red; blue is just a colour used in diagrams. |
Worksheet answers
- Nose → trachea → bronchi → bronchioles → alveoli.
- The space inside the bottle got bigger, air came in through the straw and the balloon inflated, like the lungs when the diaphragm moves down.
- The right side pumps blood to the lungs and the left side pumps it to the body: two pumps in one heart.
- Right atrium top-left of the diagram (the person's right), left atrium top-right, ventricles below them.
Quiz answers
- What are the tiny air sacs at the end of the bronchioles called? Alveoli. Alveoli are where gases pass into and out of the blood.[2]
- What does the diaphragm do when you breathe in? Tightens and moves down. Moving down makes room for the lungs to fill.[3]
- Which side of the heart pumps blood to the lungs? The right side. The right side sends oxygen-poor blood to the lungs.[1]
- What do the valves in the heart do? Keep blood flowing in one direction. Valves stop the blood flowing backwards.[1]
- Arteries carry blood… away from the heart. Veins bring blood back; arteries take it away.[4]
- Which gas moves from the blood into the alveoli? Carbon dioxide. Carbon dioxide leaves the blood and is breathed out.[2]
Going further
How could you change the model to show both lungs? Try it with a Y-shaped tube and two balloons.
Sources used in this lesson
- [1] How the Heart Works: Anatomy (National Heart, Lung, and Blood Institute (NIH, USA)): reliability High
- [2] How the Lungs Work: The Respiratory System (National Heart, Lung, and Blood Institute (NIH, USA)): reliability High
- [3] How the Lungs Work: What Breathing Does for the Body (National Heart, Lung, and Blood Institute (NIH, USA)): reliability High
- [4] Biology, 40.3 Mammalian Heart and Blood Vessels (OpenStax, Rice University): reliability High
Full list with links and a note on each source's reliability: echoesof.science/school/heart-and-lungs/sources/
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