For kids, parents and teachers. Grown-ups, the short version: read it aloud, then do the experiment together.
How do your lungs work?
Think of your lungs as two big, squishy sponges in your chest. They can’t move by themselves. They need a helper, and that helper is your diaphragm (say it: DIE-uh-fram), a strong muscle that sits right underneath them.
When the diaphragm moves down, your chest gets bigger and air rushes in. When it moves back up, your chest gets smaller and the air gets pushed out. Put your hand on your tummy and you can feel it happening.
What is the journey of a breath?
- NoseAir comes in and gets warmed up. Tiny hairs called cilia catch dust. (Bogeys have a job after all.)
- ThroatThe air heads down the back of your throat. Your food uses this same hallway!
- WindpipeThis tube, also called the trachea, takes air down into your chest.
- LungsThe tube splits in two, then into smaller and smaller branches, like an upside-down tree.
- Air sacsAt the end of each branch are teeny bubbles called alveoli. Here, oxygen jumps into your blood and carbon dioxide jumps out.
- Back outYou breathe out, and do it all over again.
Want the version with all the labels? See the full respiratory system diagram, which is good for school projects.
What are some fun facts about the respiratory system?
- Your lungs aren’t twins. The right one has three parts, called lobes, and the left has two, which leaves room for your heart.
- You have hundreds of millions of air sacs. They’re so small you need a microscope to see them.
- Grown-up lungs hold about 6 litres of air. That’s about three big bottles of soda.
- A grown-up takes around 17,000 to 26,000 breaths a day. That’s 12 to 18 breaths a minute, times all the minutes in a day.
- Babies breathe much faster than you. A newborn takes about 44 breaths a minute, and a two-year-old about 26.
- Your brain is on breathing duty. It keeps you breathing even when you’re fast asleep.
- You can’t talk without your lungs. Your voice is air going through your voice box.
What’s an easy respiratory system experiment?
You’ll need a timer and a grown-up. Your job is to find out what running does to your breathing.
- Count while stillSit quietly for a minute and count each breath in. Write the number down.
- MoveDo star jumps or run on the spot for one minute.
- Count againCount your breaths for another minute. Did the number go up?
- Work out whyYour muscles were working, so your body needed more oxygen and had more carbon dioxide to get rid of.
Grown-ups: skip the running if your child has asthma that’s triggered by exercise, unless their doctor says it’s fine, and keep any inhaler close.
How do you do balloon breathing?
This one’s for when you feel wobbly, cross or too wiggly to sleep. Imagine a balloon in your tummy.
- Hands on tummySit or lie down, and get comfy.
- Fill the balloonBreathe in slowly through your nose. Feel your tummy puff up.
- Blow bubblesBreathe out slowly through your mouth, as if you’re blowing bubbles and don’t want them to pop.
- Do it three timesThat’s plenty. Stop if you feel dizzy, and breathe normally.
Balloon breaths, with a helper
In for 3, out for 5. Watch the circle get bigger as your balloon fills.
3 in · 5 out
Follow the orb: in as it grows, out as it shrinks.
Seconds per phase: 3 in · 5 out. Turn on JavaScript to use the timer.
Runs in your browser: nothing is saved or sent. For haptic taps with your eyes closed, or on your wrist, use ATHA on iPhone or Apple Watch.
Common questions
What is the respiratory system in simple words?
It is the group of body parts that helps you breathe. It brings in oxygen, which your body needs, and gets rid of carbon dioxide, which it doesn’t.
What are the main parts of the respiratory system for kids to learn?
Nose, mouth, throat, windpipe, lungs, air sacs (alveoli) and the diaphragm. That is enough for most school projects.
Why do I breathe faster when I run?
Your muscles are working harder, so they need more oxygen and make more carbon dioxide. Your brain speeds up your breathing to keep up.
Why do we breathe out?
To get rid of carbon dioxide, a waste gas your body makes as it uses energy.
When should a child’s breathing worry a parent?
Call your emergency number if a child is struggling to breathe, grunting, sucking in their stomach under the ribs, has pale, blue or grey lips or skin, or is limp or unusually unresponsive.
Where does ATHA fit in?
A note for the adults: I make ATHA, a free breathing app rated 4+. It doesn’t have a kids’ mode, and I’d rather be upfront about that. But there’s no account, no ads and nothing to buy, so it’s an easy one to sit down and share. Try Quick Reset together at bedtime, and let the shapes on the screen do the counting.
Teachers and parents, if you use this with your class or kids, tell me how it went.
Indie iOS developer, and the maker of ATHA. Say hello on Instagram or at solostaseraofficial@gmail.com.
Sources
Checked on 3 November 2026.
- KidsHealth (Nemours): Your lungs and respiratory system · Medically reviewed January 2023.
- NHLBI: The respiratory system · Last updated 24 March 2022.
- American Lung Association: Lung capacity and aging · Last updated 6 October 2026.
- Cleveland Clinic: Vital signs · Last updated 15 March 2023.
- Fleming S et al. Normal ranges of heart rate and respiratory rate in children from birth to 18 years of age. The Lancet, 2011
- American Lung Association: Breathing exercises · Last updated 22 June 2026.
- NHLBI: How your body controls breathing · Last updated 24 March 2022.
- NHS: Shortness of breath · Page last reviewed 30 January 2024.
ATHA is a breathing and mindfulness app, not a medical device, and this guide is general information, not medical advice. It doesn’t diagnose or treat any condition. For a symptom that is persistent, severe or worrying, talk to a doctor. In an emergency, call your local emergency number.