We know that you can replace the air in a bottle with water if you submerge that bottle in water. (The bubbles of air come out while the water goes in).
So, can you replace water in a bottle with air?
Yes, you can. By blowing through a piece of tubing, you can fill air into the bottle of water, replacing the water with air.
We wondered could we find out how much air is in our body (in our lungs) by blowing as much air as possible from our lungs into the bottle.
But first we had to find a way of keeping the water in the bottle even when the bottle is upside down.
One of our class had a great idea. If you fill the bottle with water, then put your hand over the opening, then turn the bottle upside down and put it into the basin of water before taking your hand away, then the water will stay in the bottle. This worked perfectly!
Next we tilted the bottle and popped the tubing into the bottle.
Then we blew as hard as we could for as long as we could (ONE BREATH ONLY).
The amount of air in the bottle = the amount of air that came out of our lungs.
We tried this with a student and then a teacher because we wondered if teachers have bigger lungs. Yes, we found that they have. Is this because the teacher is bigger or is it because she talks more? We haven't found an answer to that question yet!
We then had a look at our human model to see what lungs actually look like and where exactly they sit inside our bodies.
