holding pressure/volume constant

[Payton Kammerer 2B]

I've generally noticed that we tend to alternately hold either pressure of volume constant for certain situations in thermodynamics, and I am wondering what the benefits are to each and what different ways that might be accomplished in a field setting. So much of what we learn is lab-based, but how might an ecologist do these experiments while in a remote location? How do you do that with a living organism, when things like blood pressure and volume are constantly in flux?

[vpena_1I]

I'm guessing if you want certain measurements to be accurate, you'd wanna use a model in which you can control all variables. I don't think doing the kinds of experiments we talk about are very helpful in the situations you're describing.

[Tauhid Islam- 1H]

I think that by holding pressure and volume constant, we can observe certain phenomenon through a more systematic, concrete and mathematically fitting lens. Through this experimentation, we are able to learn a lot of chemistry and how certain chemically properties like thermodynamics and the flow of energy in chemical reactions work. It's not entirely representative of reality, but creating ideal conditions and observing that gives us a good baseline estimate to go off.

[Lorraine Jiang 2C]

I think we hold either volume or pressure to be constant in experiments or calculations because these two things are important in chemistry and biology. When we want to test the effect of changing pressure, we must hold volume constant as a control variable. When we want to see the effect of changing volume, we must hold pressure as a constant.

Hope it helps!