Kabir and I read about breathing. So, we followed the instruction of a breathing experiment we found online.
We found an empty Sprite bottle. We filled it up with 1 cup of water at a time and marked the bottle for each cup on a masking tape.
Then Amit inverted the bottle in a bowl with water. He made sure that one end of the plastic tube was in the bottle. Kabir took a deep breath and then breathed out in the plastic tube. He was able to displace about 3 to 3 1/2 cups of water from the bottle each time. The bottle was empty by the third time of breathing out. Arjun refused to take part in the experiment.
After this, Amit and Kabir had a long discussion about asthma, vital breath capacity and so on. It was enlightening as I learnt a few things too!
Additionally, we did a simple experiment where we had a race of blowing cotton. Arjun refused to take part in the race and so it was just Kabir and me. Of course, Kabir won! At first, we tried to blow the cotton using a long paper roll and then we used a straw. It was much faster to blow the cotton with a straw. I told him to pay attention to how his lungs and muscles around there goes in and out as he tries to blow out a deep breath.