How to Build a Spirometer
A spirometer is an instrument used to measure lung capacity. Spirometers are used by medical professionals to test the breathing of patients with asthma or other lung disorders. When the patient blows into the spirometer, the exhaled air displaces the water and indicates how much air was in the patient's lungs. A real doctor's spirometer is quite expensive, so the steps below explain how to make a spirometer cheaply at home with everyday materials.
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Things You'll Need
- Duct tape
- Measuring cup with milliliters
- Water
- Permanent marker or black crayon
- 3-liter Glass jar with lid
- Bucket
- 3' piece of Plastic tube
Instructions
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1
Stick a piece of duct tape to the outside of the jar from top to bottom. Make sure it's thoroughly attached so that it will stay on when it goes underwater.
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2
Fill the measuring cup with 500ml water and pour it into the jar.
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3
Mark the 500ml on the duct tape at the top of the water level.
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4
Repeat step 2 until the jar is full. With each 500 ml pour, mark the duct tape with the amount of water added: 1000ml, 1500ml, etc. The duct tape will be the spirometer's measure to see how much air goes into it.
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5
Screw the lid onto the jar.
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6
Fill the bucket with water. There should be enough water that you can push the jar completely underwater.
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7
Turn the jar upside-down and put it into the bucket. Holding the jar completely underwater, unscrew the lid. You do not want any air to get into the jar.
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8
Holding the jar with one hand, slide one end of the plastic tube inside the jar with the other end outside the bucket. Make sure the tube isn't crimped and that the jar isn't smashing it, or air won't be able to go in easily. The tube end outside the bucket is where you'll blow into the spirometer.
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9
Blow into the tube. The bubbles from your breath will displace the water in the jar and tell you how much air you've exhaled, using the measurement markings on the duct tape.
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10
To repeat the test or test other people, be sure to refill the jar completely with water before submerging it and putting the tube back in.
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Tips & Warnings
You can show children how they're growing by measuring their lung capacity every few months---it should increase as their lungs become larger.
Resources
- Photo Credit Image courtesy of Wikipedia Commons
