The respiratory system
🌟 This Topic is About...
- 💨 I will learn how the respiratory system works.
- 🫁 I will make and explain a model of breathing.
- 🌬️ I will discover that breathing has two stages — breathing in and breathing out.
- ⏱️ I will measure how fast I breathe and record my results.
- 🧪 I will carry out experiments safely and record data in a table.
- 📈 I will draw a line graph and use it to make conclusions.
- 🔍 I will find information to answer a scientific question.
Get ready to explore how your lungs keep you alive! 🌬️💙
🌟 Key Words
- breathing
- breathing rate
- diaphragm
- lungs
- windpipe
📖 Tap to Learn the Meanings!
- 💨 breathing: Taking air in and out of your lungs to get oxygen and remove carbon dioxide.
- ⏱️ breathing rate: How many times you breathe in one minute.
- 🫁 diaphragm: A muscle under your lungs that helps you breathe in and out.
- 🌬️ lungs: The organs in your chest that fill with air when you breathe.
- 🧵 windpipe: The tube that carries air from your mouth and nose to your lungs.
Great job learning new science words! 🎉
💨 Parts of the Respiratory System
The human respiratory system contains several important parts that help us breathe. These include two lungs, air tubes leading from the mouth and nose to the lungs, and muscles in the chest that move air in and out of the lungs.
🫁 The Lungs and Breathing
We use our lungs for breathing, which keeps us alive. Breathing involves taking air in and pushing it out — we breathe in (inhale) and breathe out (exhale).
The lungs sit in the chest and are protected by the ribs. They are soft and stretchy, like sponges that fill up with air each time we breathe in.
💨 Breathing and Oxygen
We need oxygen to live. When we breathe in, oxygen gas from the air moves into the blood vessels in the lungs. Blood carries this oxygen to the heart and then to other parts of the body.
🌬️ Breathing Out Carbon Dioxide
As the body uses up oxygen, it produces carbon dioxide. The blood carries this carbon dioxide back to the lungs, where it leaves the body when we breathe out.
🫁 How Breathing Works
When you breathe in, air enters through the nose or mouth and travels down the windpipe into the lungs. The ribs move upwards and outwards, and the diaphragm muscle contracts and moves downwards. This makes the chest bigger and fills the lungs with air.
When you breathe out, the ribs move downwards and inwards, and the diaphragm relaxes and moves upwards. The chest gets smaller, and air is pushed out of the lungs through the nose or mouth.
🔍 Think Like a Scientist 1: Make a Model to Explain Breathing
🧰 You will need: a plastic bottle, a narrow plastic tube or straw, an elastic band, scissors, two balloons, electrical tape, sticky putty or plasticine play dough.
🛡️ Safety First:
- Take care not to cut yourself with the scissors or the sharp edge of the cut bottle. ✂️⚠️
📝 Method:
- Cut the bottom off the plastic bottle.
- Tie a knot in the narrow end of one balloon and cut off the other end.
- Stretch the newly cut end of the balloon around the bottom of your plastic bottle. Use electrical tape to fix the balloon in place.
- Put a plastic tube or straw in the neck of the other balloon and fix it with the elastic band. Don’t make the band too tight — the air must flow through. Blow gently through the straw to see if the balloon inflates.
- Put the straw and balloon into the neck of the bottle. Use play dough around the neck to seal the bottle, but don’t crush the straw.
- a) Pull on the bottom balloon and observe what happens.
b) Let go of the balloon. What happens?
❓ Questions:
- a) lungs
- b) the chest cavity
- c) the windpipe
- d) the diaphragm muscle
👀 Show Answers
- 1. a) Small balloon = lungs 🫁
b) Plastic bottle = chest cavity 🧍
c) Straw = windpipe 🌬️
d) Big balloon = diaphragm 💪 - 2. The ribs and chest muscles are not shown in this model.
- 3. When you pull the bottom balloon, air enters the lungs. When you let go, air is pushed out — just like real breathing!
Fantastic work, young scientist! 🌟🧠
💨 Breathing Rate
We breathe in and out about 16 times every minute. The number of times we breathe in and out in one minute is called our breathing rate. Our breathing rate changes depending on how much oxygen our body needs.
🔍 Think Like a Scientist 2: Investigate Breathing Rate
🧰 You will need: a timer or watch with a second hand ⏱️
📝 Method:
- Count the number of breaths you take per minute while at rest. Record this in a table.
- Run on the spot for two minutes and then stop. Count and record your breathing rate again.
- Run on the spot for another two minutes and then stop. Count and record the number of breaths per minute.
- Wait two minutes and record your breathing rate again. Repeat once more after another two minutes.
- Draw a line graph of your breathing rate.
- a) When was your breathing rate lowest?
b) How did exercise affect your breathing rate? Suggest a reason for this.
c) Use your graph to work out how long it took your breathing rate to return to normal after exercising. - Use your results to write a conclusion for the investigation.
- Suggest another factor that could affect a person’s breathing rate (think about athletes and sports players).
- Identify which type of scientific enquiry you used in this investigation.
- Name another body system that is also affected by exercise.
💭 How am I doing?
- Was I able to measure my breathing rate accurately?
- Was I able to draw a clear line graph of my results?
- Was I able to use my results to make a conclusion?
- Do I understand how exercise affects breathing rate?
👀 Show Answers
- 1–3: Your breathing rate increases during exercise because your muscles need more oxygen and produce more carbon dioxide.
- 4: It gradually returns to normal as your body recovers.
- 5: The type of enquiry used is observing and measuring changes.
- 6: The circulatory system is also affected by exercise. ❤️
Fantastic investigation — you’re thinking like a real scientist! 🌟🧠