Lung Model

Breathe in. Breathe out. Do you feel your chest expand and shrink when you breathe? That change in size is how you get air into your lungs! It all has to do with the physics of air pressure, which you’ll investigate in this project.

Want to explore anatomy without the hassle of gathering materials? Dive into learning with a Vet Starter Kit from the KiwiCo Store

  1. Ages: 7 - 16

  2. 30 minutes - 1 hour

  3. Messy

Tags:

Materials you'll need

Step-by-step tutorial

  • Step 1

    Gather your materials!

    Photo reference of how to complete step 1

  • Step 2

    Cut the necks off of two of the balloons.

    Photo reference of how to complete step 2

  • Step 3

    Cut one straw in half. Then, attach one balloon to each straw half. Use tape to seal it off. These will be your “lungs.”

    Photo reference of how to complete step 3

  • Step 4

    Take the other straw and make a 2" (5.08 cm) cut on one end so that it is split in half.

    Photo reference of how to complete step 4

  • Step 5

    Flip the straw around and make two 2” cuts on the other end so that it is split into four.

    Photo reference of how to complete step 5

  • Step 6

    Tape one “lung” on either side of the two-way split straw.

    Photo reference of how to complete step 6

  • Step 7

    Cut off the bottom of the bottle.

    Photo reference of how to complete step 7

  • Step 8

    Remove the bottle cap and make a hole in the cap large enough to fit a straw through it.

    Photo reference of how to complete step 8

  • Tip

    We made the hole using a pushpin and then widened it with scissors.

  • Step 9

    Place your “lungs” inside the bottle, so that the balloons hang towards the bottom. Then, poke the four-way split end of the straw through the hole in the cap. Screw the cap back onto the bottle. 

    Photo reference of how to complete step 9

  • Tip

    You may need to shorten your straw based on the size of your bottle. If it’s too long, shorten the straw so that the lungs are about 2” from the bottom of the bottle. Then, make the four-way split again.

  • Step 10

    Tape each of the split ends to the cap.

    Photo reference of how to complete step 10

  • Step 11

    Cut the neck off of the last balloon and stretch it over the bottom of the bottle.

    Photo reference of how to complete step 11

  • Step 12

    Pull on the bottom balloon to see a simulation of how lungs work!

    Photo reference of how to complete step 12

  • Learn moremagnifying icon graphic

    Air pressure is a measure of how strongly air presses on things. It depends on a few factors, but one of the most important is volume, or the amount of space the air has. If you’ve ever pressed on a balloon to try to make it smaller, you’ve probably noticed that it gets harder to press the smaller you make it. That's because air pressure increases when you shrink the volume (like when you squish a balloon). The squished air pushes back harder against you. The reverse is also true: air pressure decreases when you increase the volume.

    Air always tries to balance out pressure, so it will move from areas of high pressure to areas of low pressure. Your body uses this fact to move air in and out when you breathe. To breathe in, you expand your chest. That increases the volume in your lungs, which lowers their air pressure. Air rushes in to balance out the pressure. Then to breathe out, you shrink your chest, raise the air pressure in your lungs, and let the air rush back out. 

You might also like

Top categoriesBurst graphic

Share what you made & tag us at!

;