One of the most widely used inventions in medical science is, without a doubt, the spirometer. This interesting device is able to measure the patient's lung capacity quickly and efficiently, using some physical theories as a basis, such as the impermeability of bodies, making it a good choice for a science project. Today, we will look at how to make a homemade spirometer in a simple way and in very few steps.
- 3L PET bottle (soft drink bottles).
- Transparent hose.
- Plastic canister.
How to create our spirometer
The first thing we are going to do is to remove any labels or stickers from the bottle so that it is completely transparent. Next, we are going to graduate it with the help of a ruler and an indelible marker, approximately every 1/8 of a litre or every 1/4 of a litre.
Once the bottle is graduated, fill the plastic bottle to about three-quarters of the way up to the rim. Then fill the bottle with water and insert one end of the hose through the mouth of the bottle.
Now, we cover the mouth of the bottle with our hand and turn it upside down, and in this inverted form, we place it inside the bottle with water, making sure that the other end of the hose is outside the plastic bucket, thus, our spirometer is ready.
Performing the first test
To see the spirometer working, we must take in as much air as we can and exhale it through the free end of the hose. You will see that the water will overflow the plastic canister and fall through it. When we have no more air, we check how far the water reaches inside the graduation of the bottle, thus, we will see what is the lung capacity of the person performing the test.
How it works
The principle of impermeability of bodies states that two bodies cannot occupy the same place at the same time. It is for this reason, that when we insert air into our home-made spirometerThe water is displaced by the air, so that it overflows and is pushed upwards into the bottle, thus measuring the amount of air entering the device.