How Big Are Your Lungs?

Health Science
Time 1 hour
Age 7 & up
Group Size 4 or more
Tags Air, Body, Breath,   more...
Lungs Measurement

How much air can your lungs hold?

Children’s bodies are undergoing constant change.  By getting to know their own bodies better, these changes can be less mysterious.  Children who are in tune with their own bodies can use all of their senses as tools as they explore and try to understand the world around them.  This activity will help children learn more about their lungs.

Preparation

1) Gather the tubing – several sizes different sizes of tubing can work, but make sure that the tubing used to make the mouthpieces has an outer diameter that matches the inner diameter of the flexible tubing.  For instance, if you use the suggested size of ¼” ID (Inner Diameter) flexible tubing, make sure you get ¼” OD (Outer Diameter) rigid tubing to make the mouthpieces out of, because these need to slip inside the flexible tubing.  Tubing can be purchased at aquarium supply stores, some hardware stores and several online plastics manufacturers. See Suggestions (under “Make it Better”) for online ordering.

2) Cut the mouthpieces – each child will need a single 3” piece of rigid tubing.  Make a few extras, as some will get lost or fall on the floor.  Some rigid tubing can be cut with scissors, some is easier to cut if you simply slice a bit into it and then bend the tubing where you sliced it.  It should break cleanly.  Flexible tubing cuts well with a utility knife or scissors.

3) Calibrate the 1-gallon jug – you can choose to measure in cups or liters, whichever you prefer.  Pour 1 cup or ½ liter (small soda bottles are usually ½-liter) of water into the 1-gallon jug.  Draw a line with permanent marker where the water level is, and write “1” (if cups) or “½” (if liters) next to the line.  Pour in another cup or half liter, draw a line at the water level and mark “2” (for cups) or “1” (for liters).  Continue this process until the gallon jug is full.

4) Fill the large bin with water – the bin should be big enough so that if you hold the gallon jug upright and touching the bottom of the bin, the water level will be higher than the top of the jug.  Make sure to either fill the bin where you want to do the activity, or fill it on a cart so you can move it – when it’s filled with water, the bin will be very heavy!

How Big Are Your Lungs?
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Suggested Materials

  • Ziploc bags of various sizes (20 of each size)
  • Drinking straws (1 per child)
  • 1-gallon plastic jug, clear
  • Large bin (13”–17” deep)
  • Flexible or semi-flexible plastic or vinyl tubing (5–6 feet; see Preparation)
  • Rigid or semi-flexible plastic tubing, for mouthpieces (8–10 feet; see Preparation)
  • Box cutter/utility knife
  • Scissors
1

Make it Matter

Opening Discussion

Ask your students how big they think their lungs are.  Hold up a ½-liter, a 1-liter, a 2-liter and a gallon bottle, and ask them to estimate which is closest to the amount of air their lungs can hold in 1 breath.

The Challenge

Measure how much air your lungs can hold!

2

Make it Happen

Doing the Activity

  1. Show your students the Ziploc bags.  Ask them to choose the size that they think is closest to the size of their lungs (have 1-pint, 1-quart and 1-gallon bags available).
  2. Hand a straw out to each child and demonstrate blowing up a bag with a straw.  Place one end of the straw in your mouth, and the other end of the straw in the Ziploc bag.  Zip the Ziploc almost closed, until it zips right up to the straw.  Take a deep breath, blow the entire breath into the bag, pull the straw out and quickly zip the bag closed.
  3. Have your students try with the bag they’ve chosen.  If they find their bag to be too big or too small, they can pick another size.
3

Make it Click

Let’s Talk About It

After 5 minutes of this activity, when every child has blown up a bag, stop your students and bring them together to share their observations with each other.  Were their predictions correct?  Did anything surprise them?  Have them look at their bags.  Do they see anything inside?  What do they think it is?  They should notice water inside their bag.  This is caused by water vapor that is released every time we breathe out.  Does everyone have the same lung capacity?  What might affect how much air our lungs can hold?  This discussion should last no more than a few minutes.

4

Make it Better

Build On What They Talked About

Introduce the second activity—a more precise way of measuring lung capacity or size:

  1. Show your students the large bin of water and tell them that they’ll now be measuring their lung capacity more accurately.  Hand out the mouthpieces.
  2. Place the jug into the bin and fill the jug with water.  Make sure you fill it to the top.
  3. With the filled jug under water, put your hand tightly over the mouth of the jug and turn it over so that the mouth of the jug is underwater, facing down and that no water spills out.
  4. You can take your hand away from the mouth of the jug, and as long as you don’t pull the mouth up past the top of the water level in the bin, the water will stay in the jug.  You can raise most of the jug out of the water so that your students can see the levels you marked on it, but again, make sure the opening of the jug stays under water.
  5. Place an end of the long flexible tubing up into the filled jug.  Hand the other end to a volunteer and ask them to put their mouthpiece into the tubing.  Make sure they don’t push it in too far—this will make it difficult to get it out.
  6. The volunteer should take a deep breath and blow into the tube.  This will force air into the jug, pushing water out.  When the child has blown 1 full breath, quickly remove the tube from inside the jug, reach down and cover the mouth of the jug with your hand so the water won’t come out.  Lift the jug up and check where the water level is.  Whatever the measurement is will equal that child’s lung capacity.  Have them record their lung capacity.  Repeat this for each child in the class.

Suggestions

  • Purchasing Tubing – Aquarium supply stores carry flexible tubing (and some carry rigid tubing as well); as do many hardware stores.  For your shopping ease, we have included links and part numbers for ordering online at McMaster-Carr.  McMaster-Carr (click here to visit their website) is a great website for all sorts of stuff you need, and even more materials you had no idea you needed. Think of it as the biggest hardware store you’ve ever been in. Ever.:
    • Rigid Tubing – Hardwall, rigid PVC tubing is best – part number 53945K111 (click here for product page) is 70 cents/foot.  You should get 4-6 mouthpieces per 1-foot tube.  You want the 1/4″ outside diameter (remember, it needs to fit in the 1/4″ inside diameter flexible tubing); with the .04″ wall thickness.  These tubes come in 1-foot lengths.  You can order 3-foot tubes (part# 53945K113); or 6-foot lengths (part# 53945K116), which end up costing less per foot, but require more cutting on your part.
    • Flexible plastic tubing – Definitely go with the “Masterkleer” PVC tubing – it’s inexpensive (around 20 cents/foot) and works well. Click here for the product page for the correct type tubing. Select the 1/4″ inside diameter; 1/16″ wall thickness; and clear tubing.
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