Isolated Systems

[Eva Guillory 2E]

Regarding Isolated systems (other than the example of the entire universe, which Lavelle mentioned in class), is there any way we can prove that other so-called isolated systems are actually 100% isolated?

[Riya Shah 4H]

I don't think that any system except the universe is 100% isolated. But examples of an isolated system can be water in an insulated bottle.

[Summer de Vera 2C]

I would disagree with the above statement. I'm pretty sure something as a simple as a liquid in a thermos is an isolated system because it's insulated to prevent any heat from escaping and, while it's sealed, there's no transfer in any matter that occurs. Also, there are things called bomb calorimeters that measure the meat of a combustion reaction, which is also an isolated system.

[Chris Freking 2G]

The bomb calorimeter is also an example of an "isolated system."

There is no truly 100% isolated system other than the universe (arguably). But we refer to a high-quality sealed thermos or a bomb calorimeter as an isolated system because the heat transfer is so slow that it can be approximated to 0.

(For example, your high-quality thermos will keep a liquid very hot for a few hours, but probably not for a few days. But since the heat transfer is so slow it's approximated to 0 for our use of thermodynamic problems)

[fgalasso1b]

It is determined whether the system exchanges matter and energy with the surroundings. Since there's no surroundings around the universe, it's isolated.

[JadeSebti1L]

There are no actually isolated systems other than the universe, but I think for the sake of this class we just assume an isolated system is merely one that does not exchange energy or matter with its surroundings. ex: soup in a closed thermos, bomb calorimeter, etc.

[Raj_Bains_2C]

I don't think that there is any way to prove 100% isolation of any system except for the universe. Even an insulated water bottle or thermos has a very small amount of heat lost, so it is not completely 100% isolated. But, as Lavelle explained in lecture, that heat lost is extremely small compared to the energy of the surroundings, so it is negligible and we can approximate 100% isolation.