Lungs at Work
Learning Objectives
Students will be able to:
- Explain how the diaphragm helps us breathe
- Build a working model of lungs
- Describe what happens when we inhale and exhale
- Compare breathing at rest vs. after exercise
The Big Question
"How do your lungs pull air in and push it out?"
Materials Needed
For Each Lung Model:
- 1 plastic bottle (clear, 500mL or 1L, with bottom cut off)
- 2 balloons (same size)
- 1 larger balloon or rubber glove (for diaphragm)
- 1 straw or plastic tubing
- Tape and rubber bands
- Scissors (teacher use)
How Breathing Works
Your lungs cannot move on their own! They need help from a special muscle called the diaphragm (say: DY-uh-fram).
Breathing IN (Inhale)
- Your diaphragm pulls DOWN and flattens
- This makes more space in your chest
- Your lungs expand (get bigger)
- Air rushes IN to fill the space
Breathing OUT (Exhale)
- Your diaphragm relaxes and moves UP
- This makes less space in your chest
- Your lungs get smaller
- Air is pushed OUT
Activity: Build a Lung Model (25 minutes)
Step-by-Step Instructions:
Step 1: Prepare the Bottle (Teacher)
Cut off the bottom of the plastic bottle. This bottle represents your chest cavity (rib cage).
Step 2: Make the Lungs
Attach a balloon to the end of the straw with a rubber band. This balloon is your "lung." The straw is your "windpipe."
Step 3: Insert the Windpipe
Push the straw through the bottle opening so the balloon hangs inside. Seal around the straw with tape or clay so no air can escape.
Step 4: Make the Diaphragm
Cut the large balloon in half. Stretch it over the bottom opening of the bottle. Secure with a rubber band. This is your "diaphragm."
Step 5: Test It!
Pull down on the diaphragm (large balloon) - watch the lung (small balloon) inflate! Push up on the diaphragm - the lung deflates!
What Each Part Represents
| Model Part | Body Part | What It Does |
|---|---|---|
| Plastic bottle | Chest cavity / Rib cage | Protects the lungs |
| Straw | Windpipe (trachea) | Carries air to the lungs |
| Small balloon | Lung | Fills with air |
| Large balloon on bottom | Diaphragm | Muscle that makes breathing happen |
Activity: Measure Your Breathing (10 minutes)
How Fast Do You Breathe?
- At Rest: Sit quietly. Count how many breaths you take in 1 minute. Write it down.
- After Exercise: Do 20 jumping jacks. Immediately count your breaths for 1 minute. Write it down.
- Compare: What happened to your breathing rate after exercise?
Record Your Data:
| Breaths at rest (1 minute): | _______ breaths |
| Breaths after exercise (1 minute): | _______ breaths |
Why Does This Happen?
When you exercise, your muscles need more oxygen to make energy. Your body breathes faster to bring in more oxygen and get rid of extra carbon dioxide!
The Diaphragm is a Super Muscle!
Location
The diaphragm is a dome-shaped muscle below your lungs. It separates your chest from your belly.
Always Working
Your diaphragm works automatically - you don't have to think about breathing! It works even when you sleep.
Think About It!
Discussion Questions:
- What happens when you hiccup? (Hint: Your diaphragm has a spasm!)
- Why can you choose to hold your breath, but you can't stop breathing forever?
- What do you think happens to someone with asthma when their airways get narrow?
Science Notebook (5 minutes)
Draw and answer:
- Draw your lung model and label each part
- Explain what happens when you pull down on the diaphragm
- Why did your breathing rate increase after jumping jacks?
Key Takeaways
- The diaphragm is a muscle that makes breathing happen
- When the diaphragm pulls down, lungs expand and air comes IN
- When the diaphragm relaxes up, lungs get smaller and air goes OUT
- We breathe faster during exercise because our body needs more oxygen
Vocabulary Words
Diaphragm
The dome-shaped muscle below your lungs that controls breathing.
Inhale
To breathe in. Air enters your lungs.
Exhale
To breathe out. Air leaves your lungs.
Breathing Rate
How many breaths you take in a certain amount of time.