Near the end of an experiment during one of my lab courses one day, I blew like 'HOOO' (where the air you blow is cold) onto a small container of water which had a pH probe. Then, I blew like 'HAAA' (where the air you blow is hot).
I noticed that, perhaps by sheer coincidence, the pH of the water decreased by a small amount when I blew like 'HAAA'. My hypothesis was that maybe blowing like 'HAAA' released more CO2 which was absorbed by the water, making it more acidic.
Unfortunately, I didn't have enough time to test my hypothesis further and we aren't going to use the pH probes for the rest of our experiments, so I can't test it later on, either.
So, I'm wondering: does blowing 'HAAA' release more CO2 than blowing 'HOOO'? Or was this purely a coincidence?