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### 1st law of thermodynamics

Posted: Fri Feb 01, 2019 3:11 pm
How does the universe being an isolated system prove the first law of thermodynamics?

### Re: 1st law of thermodynamics

Posted: Fri Feb 01, 2019 4:13 pm
An isolated system is where energy exchange and transfers are bounded by the system. The universe is the closed system and cannot exchange energy with its surroundings for there may not be one. Therefore it is considered that the universe contains everything. Every energy transformation is within the universe and thus energy is conserved in this system since energy cannot exit.

### Re: 1st law of thermodynamics

Posted: Fri Feb 01, 2019 4:17 pm
When energy goes into the surroundings in an experiment, it is not lost. It is just going into the universe. The fact that the universe is an isolated system means that it does not lose energy, so energy is conserved overall. The total energy in the universe never changes.

### Re: 1st law of thermodynamics

Posted: Fri Feb 01, 2019 5:10 pm
Essentially no energy is lost in the universe since the universe accounts for all matter and everything. There is nothing larger than the universe so no energy is transferred out or in and no matter is added or lost in the universe.

### Re: 1st law of thermodynamics

Posted: Fri Feb 01, 2019 8:28 pm
The first law of thermodynamics says that matter cannot be created or destroyed, and that the internal energy of an isolated system is constant. The universe is an example of such a system because all the energy in the universe is conserved and cannot be lost or created. No matter what happens in the universe, there will be no net change in energy.

### Re: 1st law of thermodynamics

Posted: Sun Feb 03, 2019 5:02 pm
Since all matter can not be created nor destroyed, all the internal energy of an isolated system will remain constant.

### Re: 1st law of thermodynamics

Posted: Sun Feb 03, 2019 5:06 pm
The first law of thermodynamics is the conservation of energy, meaning that the internal energy of an isolated system is constant. This relates to the universe because the universe is an isolated system, and therefore the energy within it is constant.

### Re: 1st law of thermodynamics

Posted: Sun Feb 03, 2019 7:36 pm
An isolated system means that there is no matter or energy change/transfer between the internal objects and their surroundings. Using the universe as an example - there is nothing known outside of the universes therefore it is impossible for energy or matter to be transferred to the surroundings because it doesn't exist.