That experiment was about cooling, not dilution. You could do the cooling measurement here, too; it wouldn't much influence the outcome.

SO THE PATH FROM MECHANICAL ENGINEERING TO MIXING TELEVISION

When I was working on my pre-engineering I took a couple classes in mixing in order to make my keyboard stuff sound better. When I transferred I decided to see if I could get a job mixing bands in clubs to help pay the bills. mission accomplished; in addition to a full engineering load, I mixed a good 50-60 hours a week for my last three years of college.

When you spend that much time with sound, you hear "acoustics" muttered about in much the same way "latin" was likely muttered about in pre-Enlightenment Europe. However, since I was pursuing a mechanical engineering degree, and since acoustics is an offshoot of fluid mechanics, "acoustics" was an undeclared minor I could pursue. It was also handy in bioengineering, the other job I had in addition to mixing in clubs. Bioacoustics is interesting in and of itself; not only that, but the fluid mechanics of blood are so horrifically non-linear that they teach you that life happens in the empirical regime.

"building awesome contraptions" is something that most MEs don't do much of. In my market, my choices were thus:

1) designing logging and paper-processing equipment for Weyerhauser

2) designing construction equipment for Genie

3) designing subsystems for Boeing

4) designing HVAC systems for any number of mechanical contractors

In pursuit of employment, I ended up applying to a firm that did HVAC design, acoustical consulting and audiovisual design. they were looking for an HVAC CAD guy; I mentioned that I had post-grad stuff in acoustics and had paid for college by mixing bands in clubs. Which is how I ended up being the youngest acoustical consultant west of the Mississippi.

Acoustics is actually all mechanical engineering. Problem is, fluid mechanics doesn't work unless air is a massless particle, and because "sound" is energy transmitted through a fluid which means the particles must have mass. So you're yanked right out of your theoretical ivory tower and cast down into empirical curve-fitting hell. Sometimes you have to look at the problems, run some numbers, re-derive a few equations and curve-fit a whole new equation in order to get your answer. Despite my abiding hatred for math, I used my degree hella more than anyone I knew who had pursued any of steps (1)-(4) above.

And, of course, sound system design is essentially electroacoustics.